SQLite4
Check-in [4af30d63ec]
Not logged in

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Merge the NGQP branch back into trunk. Currently 12 tests are failing in src4.test (all errors are artifacts of the test code).
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 4af30d63ec895b7832e02f622f7c41355cbcc0a0
User & Date: dan 2013-07-22 12:50:40
Context
2013-07-22
13:24
Disable automatic indices at all times. They do not currently work. Needs to be fixed. check-in: 446fbd37d1 user: drh tags: trunk
12:50
Merge the NGQP branch back into trunk. Currently 12 tests are failing in src4.test (all errors are artifacts of the test code). check-in: 4af30d63ec user: dan tags: trunk
12:28
Changes necessary to get TH4 to compile again. check-in: 15e8dd41a9 user: drh tags: trunk
2013-07-20
20:20
Fix for optimization of DISTINCT. Leaf check-in: ed333d20c7 user: dan tags: nextgen-query-planner
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/analyze.c.

445
446
447
448
449
450
451

452

453
454
455
456
457
458
459
  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regStat1 = iMem++;       /* The stat column of sqlite_stat1 */
#ifdef SQLITE4_ENABLE_STAT3
  int regNumEq = regStat1;     /* Number of instances.  Same as regStat1 */
  int regNumLt = iMem++;       /* Number of keys less than regSample */
  int regNumDLt = iMem++;      /* Number of distinct keys less than regSample */

  int regSample = iMem++;      /* The next sample value */

  int regAccum = iMem++;       /* Register to hold Stat3Accum object */
  int regLoop = iMem++;        /* Loop counter */
  int regCount = iMem++;       /* Number of rows in the table or index */
  int regTemp1 = iMem++;       /* Intermediate register */
  int regTemp2 = iMem++;       /* Intermediate register */
  int regNewSample = iMem++;
  int once = 1;                /* One-time initialization */







>

>







445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regStat1 = iMem++;       /* The stat column of sqlite_stat1 */
#ifdef SQLITE4_ENABLE_STAT3
  int regNumEq = regStat1;     /* Number of instances.  Same as regStat1 */
  int regNumLt = iMem++;       /* Number of keys less than regSample */
  int regNumDLt = iMem++;      /* Number of distinct keys less than regSample */
#endif
  int regSample = iMem++;      /* The next sample value */
#ifdef SQLITE4_ENABLE_STAT3
  int regAccum = iMem++;       /* Register to hold Stat3Accum object */
  int regLoop = iMem++;        /* Loop counter */
  int regCount = iMem++;       /* Number of rows in the table or index */
  int regTemp1 = iMem++;       /* Intermediate register */
  int regTemp2 = iMem++;       /* Intermediate register */
  int regNewSample = iMem++;
  int once = 1;                /* One-time initialization */

Changes to src/delete.c.

338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
    ** regSet. After the scan is complete, the VM will loop through the set 
    ** of keys in the RowSet and delete each row. Rows must be deleted after 
    ** the scan is complete because deleting an item can change the scan 
    ** order.  */
    sqlite4VdbeAddOp2(v, OP_Null, 0, regSet);
    VdbeComment((v, "initialize RowSet"));
    pWInfo = sqlite4WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regSet, 0, regKey);
    sqlite4WhereEnd(pWInfo);

    /* Unless this is a view, open cursors for all indexes on the table







|







338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
    ** regSet. After the scan is complete, the VM will loop through the set 
    ** of keys in the RowSet and delete each row. Rows must be deleted after 
    ** the scan is complete because deleting an item can change the scan 
    ** order.  */
    sqlite4VdbeAddOp2(v, OP_Null, 0, regSet);
    VdbeComment((v, "initialize RowSet"));
    pWInfo = sqlite4WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK, 0
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regSet, 0, regKey);
    sqlite4WhereEnd(pWInfo);

    /* Unless this is a view, open cursors for all indexes on the table

Changes to src/expr.c.

1462
1463
1464
1465
1466
1467
1468

1469
1470
1471
1472
1473
1474
1475
....
1507
1508
1509
1510
1511
1512
1513













































































































































































1514
1515
1516
1517
1518
1519
1520
**     register = 1
**   }
**
** in order to avoid running the <test if data structure contains null>
** test more often than is necessary.
*/
#ifndef SQLITE4_OMIT_SUBQUERY

int sqlite4FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Index *pIdx;
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  Vdbe *v = sqlite4GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );
................................................................................
    pParse->nQueryLoop = savedNQueryLoop;
  }
  
  return eType;
}
#endif














































































































































































/*
** Generate code for scalar subqueries used as a subquery expression, EXISTS,
** or IN operators.  Examples:
**
**     (SELECT a FROM b)          -- subquery
**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
**     x IN (4,5,11)              -- IN operator with list on right-hand side







>







 







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
....
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
**     register = 1
**   }
**
** in order to avoid running the <test if data structure contains null>
** test more often than is necessary.
*/
#ifndef SQLITE4_OMIT_SUBQUERY
#if 0
int sqlite4FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Index *pIdx;
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  Vdbe *v = sqlite4GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );
................................................................................
    pParse->nQueryLoop = savedNQueryLoop;
  }
  
  return eType;
}
#endif

/*
** This function is used by the implementation of the IN (...) operator.
** The pX parameter is the expression on the RHS of the IN operator, which
** might be either a list of expressions or a subquery.
**
** The job of this routine is to find or create a b-tree object that can
** be used either to test for membership in the RHS set or to iterate through
** all members of the RHS set, skipping duplicates.
**
** A cursor is opened on the b-tree object that the RHS of the IN operator
** and pX->iTable is set to the index of that cursor.
**
** The returned value of this function indicates the b-tree type, as follows:
**
**   IN_INDEX_ROWID      - The cursor was opened on a database table.
**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
**   IN_INDEX_EPH        - The cursor was opened on a specially created and
**                         populated epheremal table.
**
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
**
**     SELECT <column> FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephermeral table instead of an
** existing table.  
**
** If the prNotFound parameter is 0, then the b-tree will be used to iterate
** through the set members, skipping any duplicates. In this case an
** epheremal table must be used unless the selected <column> is guaranteed
** to be unique - either because it is an INTEGER PRIMARY KEY or it
** has a UNIQUE constraint or UNIQUE index.
**
** If the prNotFound parameter is not 0, then the b-tree will be used 
** for fast set membership tests. In this case an epheremal table must 
** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
** be found with <column> as its left-most column.
**
** When the b-tree is being used for membership tests, the calling function
** needs to know whether or not the structure contains an SQL NULL 
** value in order to correctly evaluate expressions like "X IN (Y, Z)".
** If there is any chance that the (...) might contain a NULL value at
** runtime, then a register is allocated and the register number written
** to *prNotFound. If there is no chance that the (...) contains a
** NULL value, then *prNotFound is left unchanged.
**
** If a register is allocated and its location stored in *prNotFound, then
** its initial value is NULL.  If the (...) does not remain constant
** for the duration of the query (i.e. the SELECT within the (...)
** is a correlated subquery) then the value of the allocated register is
** reset to NULL each time the subquery is rerun. This allows the
** caller to use vdbe code equivalent to the following:
**
**   if( register==NULL ){
**     has_null = <test if data structure contains null>
**     register = 1
**   }
**
** in order to avoid running the <test if data structure contains null>
** test more often than is necessary.
*/
int sqlite4FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Select *p;                            /* SELECT to the right of IN operator */
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  int mustBeUnique = (prNotFound==0);   /* True if RHS must be unique */
  Vdbe *v = sqlite4GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );

  /* Check to see if an existing table or index can be used to
  ** satisfy the query.  This is preferable to generating a new 
  ** ephemeral table.
  */
  p = (ExprHasProperty(pX, EP_xIsSelect) ? pX->x.pSelect : 0);
  if( ALWAYS(pParse->nErr==0) && isCandidateForInOpt(p) && prNotFound ){
    sqlite4 *db = pParse->db;              /* Database connection */
    Table *pTab;                           /* Table <table>. */
    Expr *pExpr;                           /* Expression <column> */
    int iCol;                              /* Index of column <column> */
    int iDb;                               /* Database idx for pTab */

    assert( p );                        /* Because of isCandidateForInOpt(p) */
    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
    pTab = p->pSrc->a[0].pTab;
    pExpr = p->pEList->a[0].pExpr;
    iCol = pExpr->iColumn;
   
    /* Code an OP_VerifyCookie for <table>. */
    iDb = sqlite4SchemaToIndex(db, pTab->pSchema);
    sqlite4CodeVerifySchema(pParse, iDb);

    /* This function is only called from two places. In both cases the vdbe
    ** has already been allocated. So assume sqlite4GetVdbe() is always
    ** successful here.
    */
    assert(v);
#if 0
    if( iCol<0 ){
      int iAddr;

      iAddr = sqlite4CodeOnce(pParse);

      sqlite4OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
      eType = IN_INDEX_ROWID;

      sqlite4VdbeJumpHere(v, iAddr);
    }else
#endif
    {
      Index *pIdx;                         /* Iterator variable */

      /* The collation sequence used by the comparison. If an index is to
      ** be used in place of a temp-table, it must be ordered according
      ** to this collation sequence.  */
      CollSeq *pReq = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pExpr);

      /* Check that the affinity that will be used to perform the 
      ** comparison is the same as the affinity of the column. If
      ** it is not, it is not possible to use any index.
      */
      int affinity_ok = sqlite4IndexAffinityOk(pX, pTab->aCol[iCol].affinity);

      for(pIdx=pTab->pIndex; pIdx && eType==0 && affinity_ok; pIdx=pIdx->pNext){
        if( (pIdx->aiColumn[0]==iCol)
         && sqlite4FindCollSeq(db, pIdx->azColl[0], 0)==pReq
         && (!mustBeUnique || (pIdx->nColumn==1 && pIdx->onError!=OE_None))
        ){
          int iAddr;
  
          iAddr = sqlite4CodeOnce(pParse);
          sqlite4OpenIndex(pParse, iTab, iDb, pIdx, OP_OpenRead);
          assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
          eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];

          sqlite4VdbeJumpHere(v, iAddr);
          if( prNotFound && !pTab->aCol[iCol].notNull ){
            *prNotFound = ++pParse->nMem;
            sqlite4VdbeAddOp2(v, OP_Null, 0, *prNotFound);
          }
        }
      }
    }
  }

  if( eType==0 ){
    /* Could not found an existing table or index to use as the RHS b-tree.
    ** We will have to generate an ephemeral table to do the job.
    */
    u32 savedNQueryLoop = pParse->nQueryLoop;
    int rMayHaveNull = 0;
    eType = IN_INDEX_EPH;
    if( prNotFound ){
      *prNotFound = rMayHaveNull = ++pParse->nMem;
      sqlite4VdbeAddOp2(v, OP_Null, 0, *prNotFound);
    }else{
      testcase( pParse->nQueryLoop>0 );
      pParse->nQueryLoop = 0;
    }
    sqlite4CodeSubselect(pParse, pX, rMayHaveNull, eType==IN_INDEX_ROWID);
    pParse->nQueryLoop = savedNQueryLoop;
  }else{
    pX->iTable = iTab;
  }
  return eType;
}
#endif

/*
** Generate code for scalar subqueries used as a subquery expression, EXISTS,
** or IN operators.  Examples:
**
**     (SELECT a FROM b)          -- subquery
**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
**     x IN (4,5,11)              -- IN operator with list on right-hand side

Changes to src/fkey.c.

509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite4ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment the relevant constraint counter
  ** by nIncr.  */
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0, 0, 0);
  if( nIncr>0 && pFKey->isDeferred==0 ){
    sqlite4ParseToplevel(pParse)->mayAbort = 1;
  }
  sqlite4VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite4WhereEnd(pWInfo);
  }







|







509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite4ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment the relevant constraint counter
  ** by nIncr.  */
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
  if( nIncr>0 && pFKey->isDeferred==0 ){
    sqlite4ParseToplevel(pParse)->mayAbort = 1;
  }
  sqlite4VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite4WhereEnd(pWInfo);
  }

Changes to src/select.c.

3954
3955
3956
3957
3958
3959
3960
3961
3962
3963



3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
....
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020

4021
4022
4023
4024
4025
4026
4027
....
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
....
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    ExprList *pDist = (isDistinct ? p->pEList : 0);

    /* Begin the database scan. */
    pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, &pOrderBy, pDist, 0);
    if( pWInfo==0 ) goto select_end;
    if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut;




    /* If sorting index that was created by a prior OP_OpenEphemeral 
    ** instruction ended up not being needed, then change the OP_OpenEphemeral
    ** into an OP_Noop.
    */
    if( addrSortIndex>=0 && pOrderBy==0 ){
      sqlite4VdbeChangeToNoop(v, addrSortIndex);
      p->addrOpenEphm[2] = -1;
    }

    if( pWInfo->eDistinct ){
      VdbeOp *pOp;                /* No longer required OpenEphemeral instr. */
     
      assert( addrDistinctIndex>=0 );
      pOp = sqlite4VdbeGetOp(v, addrDistinctIndex);

      assert( isDistinct );
      assert( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED 
           || pWInfo->eDistinct==WHERE_DISTINCT_UNIQUE 
      );
      distinct = -1;
      if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED ){
        int iJump;
        int iExpr;
        int iFlag = ++pParse->nMem;
        int iBase = pParse->nMem+1;
        int iBase2 = iBase + pEList->nExpr;
        pParse->nMem += (pEList->nExpr*2);

................................................................................
        sqlite4VdbeAddOp2(v, OP_If, iFlag, iJump-1);
        for(iExpr=0; iExpr<pEList->nExpr; iExpr++){
          CollSeq *pColl = sqlite4ExprCollSeq(pParse, pEList->a[iExpr].pExpr);
          sqlite4VdbeAddOp3(v, OP_Ne, iBase+iExpr, iJump, iBase2+iExpr);
          sqlite4VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
          sqlite4VdbeChangeP5(v, SQLITE4_NULLEQ);
        }
        sqlite4VdbeAddOp2(v, OP_Goto, 0, pWInfo->iContinue);

        sqlite4VdbeAddOp2(v, OP_Integer, 0, iFlag);
        assert( sqlite4VdbeCurrentAddr(v)==iJump );
        sqlite4VdbeAddOp3(v, OP_Move, iBase, iBase2, pEList->nExpr);
      }else{
        pOp->opcode = OP_Noop;
      }
    }

    /* Use the standard inner loop. */
    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, pDest,
                    pWInfo->iContinue, pWInfo->iBreak);


    /* End the database scan loop.
    */
    sqlite4WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
................................................................................

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite4VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0, 0);
      if( pWInfo==0 ) goto select_end;
      if( pGroupBy==0 ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenEphemeral table will be
        ** cancelled later because we still need to use the pKeyInfo
        */
        pGroupBy = p->pGroupBy;
        groupBySort = 0;

        /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
        ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
        ** Then compare the current GROUP BY terms against the GROUP BY terms
        ** from the previous row currently stored in a0, a1, a2...
        */
................................................................................
        }
  
        /* This case runs if the aggregate has no GROUP BY clause.  The
        ** processing is much simpler since there is only a single row
        ** of output.
        */
        resetAccumulator(pParse, &sAggInfo);
        pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, &pMinMax, 0, flag);
        if( pWInfo==0 ){
          sqlite4ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        if( !pMinMax && flag ){
          sqlite4VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
          VdbeComment((v, "%s() by index",
                (flag==WHERE_ORDERBY_MIN?"min":"max")));
        }
        sqlite4WhereEnd(pWInfo);
        finalizeAggFunctions(pParse, &sAggInfo);
      }








|

|
>
>
>










|






|
|


|







 







|











|
>







 







|

|


|

<







 







|





|
|







3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
....
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
....
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140

4141
4142
4143
4144
4145
4146
4147
....
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    ExprList *pDist = (isDistinct ? p->pEList : 0);

    /* Begin the database scan. */
    pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, pOrderBy, pDist, 0, 0);
    if( pWInfo==0 ) goto select_end;
    if( sqlite4WhereOutputRowCount(pWInfo)<p->nSelectRow ){
      p->nSelectRow = sqlite4WhereOutputRowCount(pWInfo);
    }
    if( pOrderBy && sqlite4WhereIsOrdered(pWInfo) ) pOrderBy = 0;

    /* If sorting index that was created by a prior OP_OpenEphemeral 
    ** instruction ended up not being needed, then change the OP_OpenEphemeral
    ** into an OP_Noop.
    */
    if( addrSortIndex>=0 && pOrderBy==0 ){
      sqlite4VdbeChangeToNoop(v, addrSortIndex);
      p->addrOpenEphm[2] = -1;
    }

    if( sqlite4WhereIsDistinct(pWInfo) ){
      VdbeOp *pOp;                /* No longer required OpenEphemeral instr. */
     
      assert( addrDistinctIndex>=0 );
      pOp = sqlite4VdbeGetOp(v, addrDistinctIndex);

      assert( isDistinct );
      assert( sqlite4WhereIsDistinct(pWInfo)==WHERE_DISTINCT_ORDERED 
           || sqlite4WhereIsDistinct(pWInfo)==WHERE_DISTINCT_UNIQUE 
      );
      distinct = -1;
      if( sqlite4WhereIsDistinct(pWInfo)==WHERE_DISTINCT_ORDERED ){
        int iJump;
        int iExpr;
        int iFlag = ++pParse->nMem;
        int iBase = pParse->nMem+1;
        int iBase2 = iBase + pEList->nExpr;
        pParse->nMem += (pEList->nExpr*2);

................................................................................
        sqlite4VdbeAddOp2(v, OP_If, iFlag, iJump-1);
        for(iExpr=0; iExpr<pEList->nExpr; iExpr++){
          CollSeq *pColl = sqlite4ExprCollSeq(pParse, pEList->a[iExpr].pExpr);
          sqlite4VdbeAddOp3(v, OP_Ne, iBase+iExpr, iJump, iBase2+iExpr);
          sqlite4VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
          sqlite4VdbeChangeP5(v, SQLITE4_NULLEQ);
        }
        sqlite4VdbeAddOp2(v, OP_Goto, 0, sqlite4WhereContinueLabel(pWInfo));

        sqlite4VdbeAddOp2(v, OP_Integer, 0, iFlag);
        assert( sqlite4VdbeCurrentAddr(v)==iJump );
        sqlite4VdbeAddOp3(v, OP_Move, iBase, iBase2, pEList->nExpr);
      }else{
        pOp->opcode = OP_Noop;
      }
    }

    /* Use the standard inner loop. */
    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, pDest,
        sqlite4WhereContinueLabel(pWInfo), sqlite4WhereBreakLabel(pWInfo)
    );

    /* End the database scan loop.
    */
    sqlite4WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
................................................................................

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite4VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, pGroupBy, 0, 0, 0);
      if( pWInfo==0 ) goto select_end;
      if( sqlite4WhereIsOrdered(pWInfo) ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenEphemeral table will be
        ** cancelled later because we still need to use the pKeyInfo.
        */

        groupBySort = 0;

        /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
        ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
        ** Then compare the current GROUP BY terms against the GROUP BY terms
        ** from the previous row currently stored in a0, a1, a2...
        */
................................................................................
        }
  
        /* This case runs if the aggregate has no GROUP BY clause.  The
        ** processing is much simpler since there is only a single row
        ** of output.
        */
        resetAccumulator(pParse, &sAggInfo);
        pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, pMinMax, 0,flag,0);
        if( pWInfo==0 ){
          sqlite4ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        if( sqlite4WhereIsOrdered(pWInfo) && flag ){
          sqlite4VdbeAddOp2(v, OP_Goto, 0, sqlite4WhereBreakLabel(pWInfo));
          VdbeComment((v, "%s() by index",
                (flag==WHERE_ORDERBY_MIN?"min":"max")));
        }
        sqlite4WhereEnd(pWInfo);
        finalizeAggFunctions(pParse, &sAggInfo);
      }

Changes to src/sqliteInt.h.

345
346
347
348
349
350
351






352
353
354
355
356
357
358
...
527
528
529
530
531
532
533





534
535
536
537
538
539
540
...
919
920
921
922
923
924
925







926
927
928
929
930
931
932
....
1382
1383
1384
1385
1386
1387
1388


1389
1390
1391
1392
1393
1394
1395
....
1840
1841
1842
1843
1844
1845
1846

1847
1848
1849
1850
1851
1852
1853
....
1883
1884
1885
1886
1887
1888
1889

1890

1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903





















1904
1905
1906
1907
1908
1909
1910
1911

1912
1913
1914
1915
1916
1917
1918
....
1921
1922
1923
1924
1925
1926
1927

1928

1929
1930

1931
1932
1933
1934
1935
1936
1937
....
2722
2723
2724
2725
2726
2727
2728
2729

2730






2731
2732
2733
2734
2735
2736
2737
....
3125
3126
3127
3128
3129
3130
3131
3132

3133
3134
3135
3136
3137
3138
3139
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
#endif







/*
** Check to see if this machine uses EBCDIC.  (Yes, believe it or
** not, there are still machines out there that use EBCDIC.)
*/
#if 'A' == '\301'
# define SQLITE4_EBCDIC 1
#else
................................................................................

/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X)    ((int)(sizeof(X)/sizeof(X[0])))






/*
** The following macros are used to suppress compiler warnings and to
** make it clear to human readers when a function parameter is deliberately 
** left unused within the body of a function. This usually happens when
** a function is called via a function pointer. For example the 
** implementation of an SQL aggregate step callback may not use the
** parameter indicating the number of arguments passed to the aggregate,
................................................................................
#define SQLITE4_IndexCover     0x10     /* Disable index covering table */
#define SQLITE4_GroupByOrder   0x20     /* Disable GROUPBY cover of ORDERBY */
#define SQLITE4_FactorOutConst 0x40     /* Disable factoring out constants */
#define SQLITE4_IdxRealAsInt   0x80     /* Store REAL as INT in indices */
#define SQLITE4_DistinctOpt    0x80     /* DISTINCT using indexes */
#define SQLITE4_OptMask        0xff     /* Mask of all disablable opts */








/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE4_MAGIC_OPEN    0x4d06c919  /* Database is open */
#define SQLITE4_MAGIC_CLOSED  0x5f2246b4  /* Database is closed */
................................................................................
  char **azColl;   /* Array of collation sequence names for index */
#ifdef SQLITE4_ENABLE_STAT3
  int nSample;             /* Number of elements in aSample[] */
  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
  IndexSample *aSample;    /* Samples of the left-most key */
#endif
  Fts5Index *pFts; /* Fts5 data (or NULL if this is not an fts index) */


};

/* Index.eIndexType must be set to one of the following. */
#define SQLITE4_INDEX_USER       0 /* Index created by CREATE INDEX statement */
#define SQLITE4_INDEX_UNIQUE     1 /* Index created by UNIQUE constraint */
#define SQLITE4_INDEX_PRIMARYKEY 2 /* Index is the tables PRIMARY KEY */
#define SQLITE4_INDEX_FTS5       3 /* Index is an FTS5 index */
................................................................................
  union {
    Index *pIdx;                   /* Index when WHERE_INDEXED is true */
    struct WhereTerm *pTerm;       /* WHERE clause term for OR-search */
    sqlite4_index_info *pVtabIdx;  /* Virtual table index to use */
  } u;
};


/*
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
**
** The pIdxInfo field is used to help pick the best index on a
................................................................................
  ** we need a place to cache virtual table index information for each
  ** virtual table in the FROM clause and the WhereLevel structure is
  ** a convenient place since there is one WhereLevel for each FROM clause
  ** element.
  */
  sqlite4_index_info *pIdxInfo;  /* Index info for n-th source table */
};



/*
** Flags appropriate for the wctrlFlags parameter of sqlite4WhereBegin()
** and the WhereInfo.wctrlFlags member.
*/
#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
#define WHERE_NO_AUTOINDEX     0x0020 /* Do not use an auto-index search */
#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */






















/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/

struct WhereInfo {
  Parse *pParse;       /* Parsing and code generating context */
  u16 wctrlFlags;      /* Flags originally passed to sqlite4WhereBegin() */
  u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
  u8 untestedTerms;    /* Not all WHERE terms resolved by outer loop */
  u8 eDistinct;
  SrcList *pTabList;             /* List of tables in the join */
................................................................................
  int iBreak;                    /* Jump here to break out of the loop */
  int nLevel;                    /* Number of nested loop */
  struct WhereClause *pWC;       /* Decomposition of the WHERE clause */
  double savedNQueryLoop;        /* pParse->nQueryLoop outside the WHERE loop */
  double nRowOut;                /* Estimated number of output rows */
  WhereLevel a[1];               /* Information about each nest loop in WHERE */
};



#define WHERE_DISTINCT_UNIQUE 1
#define WHERE_DISTINCT_ORDERED 2


/*
** A NameContext defines a context in which to resolve table and column
** names.  The context consists of a list of tables (the pSrcList) field and
** a list of named expression (pEList).  The named expression list may
** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
** to the table being operated on by INSERT, UPDATE, or DELETE.  The
................................................................................
void sqlite4OpenTable(Parse*, int iCur, int iDb, Table*, int);
#if defined(SQLITE4_ENABLE_UPDATE_DELETE_LIMIT) \
    && !defined(SQLITE4_OMIT_SUBQUERY)
Expr *sqlite4LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,Expr*,char*);
#endif
void sqlite4DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite4Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite4WhereBegin(Parse*, SrcList*, Expr*, ExprList**,ExprList*,u16);

void sqlite4WhereEnd(WhereInfo*);






int sqlite4ExprCodeGetColumn(Parse*, Table*, int, int, int);
void sqlite4ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
void sqlite4ExprCodeMove(Parse*, int, int, int);
void sqlite4ExprCodeCopy(Parse*, int, int, int);
void sqlite4ExprCacheStore(Parse*, int, int, int);
void sqlite4ExprCachePush(Parse*);
void sqlite4ExprCachePop(Parse*, int);
................................................................................
#else
  #define sqlite4BeginBenignMalloc(X)
  #define sqlite4EndBenignMalloc(X)
#endif

#define IN_INDEX_ROWID           1
#define IN_INDEX_EPH             2
#define IN_INDEX_INDEX           3

int sqlite4FindInIndex(Parse *, Expr *, int*);
Index *sqlite4FindExistingInIndex(Parse *, Expr *, int);


#if SQLITE4_MAX_EXPR_DEPTH>0
  void sqlite4ExprSetHeight(Parse *pParse, Expr *p);
  int sqlite4SelectExprHeight(Select *);







>
>
>
>
>
>







 







>
>
>
>
>







 







>
>
>
>
>
>
>







 







>
>







 







>







 







>

>













>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>








>







 







>

>
|
|
>







 







|
>

>
>
>
>
>
>







 







|
>







345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
...
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
...
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
....
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
....
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
....
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
....
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
....
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
....
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
#endif

/* 
** Macros to compute minimum and maximum of two numbers.
*/
#define MIN(A,B) ((A)<(B)?(A):(B))
#define MAX(A,B) ((A)>(B)?(A):(B))

/*
** Check to see if this machine uses EBCDIC.  (Yes, believe it or
** not, there are still machines out there that use EBCDIC.)
*/
#if 'A' == '\301'
# define SQLITE4_EBCDIC 1
#else
................................................................................

/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X)    ((int)(sizeof(X)/sizeof(X[0])))

/*
** Determine if the argument is a power of two
*/
#define IsPowerOfTwo(X) (((X)&((X)-1))==0)

/*
** The following macros are used to suppress compiler warnings and to
** make it clear to human readers when a function parameter is deliberately 
** left unused within the body of a function. This usually happens when
** a function is called via a function pointer. For example the 
** implementation of an SQL aggregate step callback may not use the
** parameter indicating the number of arguments passed to the aggregate,
................................................................................
#define SQLITE4_IndexCover     0x10     /* Disable index covering table */
#define SQLITE4_GroupByOrder   0x20     /* Disable GROUPBY cover of ORDERBY */
#define SQLITE4_FactorOutConst 0x40     /* Disable factoring out constants */
#define SQLITE4_IdxRealAsInt   0x80     /* Store REAL as INT in indices */
#define SQLITE4_DistinctOpt    0x80     /* DISTINCT using indexes */
#define SQLITE4_OptMask        0xff     /* Mask of all disablable opts */

/*
** Some new things pulled in from SQLite3 use these macros. todo: Replace
** them with working versions.
*/
#define OptimizationDisabled(db, mask)  0
#define OptimizationEnabled(db, mask)  1

/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE4_MAGIC_OPEN    0x4d06c919  /* Database is open */
#define SQLITE4_MAGIC_CLOSED  0x5f2246b4  /* Database is closed */
................................................................................
  char **azColl;   /* Array of collation sequence names for index */
#ifdef SQLITE4_ENABLE_STAT3
  int nSample;             /* Number of elements in aSample[] */
  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
  IndexSample *aSample;    /* Samples of the left-most key */
#endif
  Fts5Index *pFts; /* Fts5 data (or NULL if this is not an fts index) */

  unsigned bUnordered:1;   /* Use this index for == or IN queries only */
};

/* Index.eIndexType must be set to one of the following. */
#define SQLITE4_INDEX_USER       0 /* Index created by CREATE INDEX statement */
#define SQLITE4_INDEX_UNIQUE     1 /* Index created by UNIQUE constraint */
#define SQLITE4_INDEX_PRIMARYKEY 2 /* Index is the tables PRIMARY KEY */
#define SQLITE4_INDEX_FTS5       3 /* Index is an FTS5 index */
................................................................................
  union {
    Index *pIdx;                   /* Index when WHERE_INDEXED is true */
    struct WhereTerm *pTerm;       /* WHERE clause term for OR-search */
    sqlite4_index_info *pVtabIdx;  /* Virtual table index to use */
  } u;
};

#if 0
/*
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
**
** The pIdxInfo field is used to help pick the best index on a
................................................................................
  ** we need a place to cache virtual table index information for each
  ** virtual table in the FROM clause and the WhereLevel structure is
  ** a convenient place since there is one WhereLevel for each FROM clause
  ** element.
  */
  sqlite4_index_info *pIdxInfo;  /* Index info for n-th source table */
};
#endif

#if 0
/*
** Flags appropriate for the wctrlFlags parameter of sqlite4WhereBegin()
** and the WhereInfo.wctrlFlags member.
*/
#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
#define WHERE_NO_AUTOINDEX     0x0020 /* Do not use an auto-index search */
#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */
#endif


/*
** Flags appropriate for the wctrlFlags parameter of sqlite3WhereBegin()
** and the WhereInfo.wctrlFlags member.
*/
#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
#define WHERE_FORCE_TABLE      0x0020 /* Do not use an index-only search */
#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */
#define WHERE_GROUPBY          0x0100 /* pOrderBy is really a GROUP BY */
#define WHERE_DISTINCTBY       0x0200 /* pOrderby is really a DISTINCT clause */
#define WHERE_WANT_DISTINCT    0x0400 /* All output needs to be distinct */



/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/
#if 0
struct WhereInfo {
  Parse *pParse;       /* Parsing and code generating context */
  u16 wctrlFlags;      /* Flags originally passed to sqlite4WhereBegin() */
  u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
  u8 untestedTerms;    /* Not all WHERE terms resolved by outer loop */
  u8 eDistinct;
  SrcList *pTabList;             /* List of tables in the join */
................................................................................
  int iBreak;                    /* Jump here to break out of the loop */
  int nLevel;                    /* Number of nested loop */
  struct WhereClause *pWC;       /* Decomposition of the WHERE clause */
  double savedNQueryLoop;        /* pParse->nQueryLoop outside the WHERE loop */
  double nRowOut;                /* Estimated number of output rows */
  WhereLevel a[1];               /* Information about each nest loop in WHERE */
};
#endif

#define WHERE_DISTINCT_NOOP      0
#define WHERE_DISTINCT_UNIQUE    1
#define WHERE_DISTINCT_ORDERED   2
#define WHERE_DISTINCT_UNORDERED 3

/*
** A NameContext defines a context in which to resolve table and column
** names.  The context consists of a list of tables (the pSrcList) field and
** a list of named expression (pEList).  The named expression list may
** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
** to the table being operated on by INSERT, UPDATE, or DELETE.  The
................................................................................
void sqlite4OpenTable(Parse*, int iCur, int iDb, Table*, int);
#if defined(SQLITE4_ENABLE_UPDATE_DELETE_LIMIT) \
    && !defined(SQLITE4_OMIT_SUBQUERY)
Expr *sqlite4LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,Expr*,char*);
#endif
void sqlite4DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite4Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite4WhereBegin(Parse*,SrcList*,Expr*,ExprList*,ExprList*,u16,int);

void sqlite4WhereEnd(WhereInfo*);
u64 sqlite4WhereOutputRowCount(WhereInfo*);
int sqlite4WhereIsDistinct(WhereInfo*);
int sqlite4WhereIsOrdered(WhereInfo*);
int sqlite4WhereContinueLabel(WhereInfo*);
int sqlite4WhereBreakLabel(WhereInfo*);
int sqlite4WhereOkOnePass(WhereInfo*);
int sqlite4ExprCodeGetColumn(Parse*, Table*, int, int, int);
void sqlite4ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
void sqlite4ExprCodeMove(Parse*, int, int, int);
void sqlite4ExprCodeCopy(Parse*, int, int, int);
void sqlite4ExprCacheStore(Parse*, int, int, int);
void sqlite4ExprCachePush(Parse*);
void sqlite4ExprCachePop(Parse*, int);
................................................................................
#else
  #define sqlite4BeginBenignMalloc(X)
  #define sqlite4EndBenignMalloc(X)
#endif

#define IN_INDEX_ROWID           1
#define IN_INDEX_EPH             2
#define IN_INDEX_INDEX_ASC       3
#define IN_INDEX_INDEX_DESC      4
int sqlite4FindInIndex(Parse *, Expr *, int*);
Index *sqlite4FindExistingInIndex(Parse *, Expr *, int);


#if SQLITE4_MAX_EXPR_DEPTH>0
  void sqlite4ExprSetHeight(Parse *pParse, Expr *p);
  int sqlite4SelectExprHeight(Select *);

Changes to src/update.c.

339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
  **
  ** There is one exception to the above: If static analysis of the WHERE 
  ** clause indicates that the loop will visit at most one row, then the
  ** RowSet object is bypassed and the primary key of the single row (if
  ** any) left in register regOldKey. This is called the "one-pass"
  ** approach. Set okOnePass to true if it can be used in this case.  */
  sqlite4VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldKey);
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0, 0, WHERE_ONEPASS_DESIRED);
  if( pWInfo==0 ) goto update_cleanup;
  okOnePass = pWInfo->okOnePass;
  sqlite4VdbeAddOp2(v, OP_RowKey, iCur+iPk, regOldKey);
  if( !okOnePass ){
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regRowSet, 0, regOldKey);
  }
  sqlite4WhereEnd(pWInfo);

  /* Open every index that needs updating. If any index could potentially 







|

|







339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
  **
  ** There is one exception to the above: If static analysis of the WHERE 
  ** clause indicates that the loop will visit at most one row, then the
  ** RowSet object is bypassed and the primary key of the single row (if
  ** any) left in register regOldKey. This is called the "one-pass"
  ** approach. Set okOnePass to true if it can be used in this case.  */
  sqlite4VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldKey);
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0,0,WHERE_ONEPASS_DESIRED,0);
  if( pWInfo==0 ) goto update_cleanup;
  okOnePass = sqlite4WhereOkOnePass(pWInfo);
  sqlite4VdbeAddOp2(v, OP_RowKey, iCur+iPk, regOldKey);
  if( !okOnePass ){
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regRowSet, 0, regOldKey);
  }
  sqlite4WhereEnd(pWInfo);

  /* Open every index that needs updating. If any index could potentially 

Changes to src/vdbe.c.

2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
      sqlite4VdbeDestroyDecoder(pCodec);
    }
  }else{
    sqlite4VdbeMemSetNull(pDest);
  }
  UPDATE_MAX_BLOBSIZE(pDest);
  REGISTER_TRACE(pOp->p3, pDest);
      assert( rc<100 );
  break;
}

/* Opcode: Affinity P1 P2 * P4 *
**
** Apply affinities to a range of P2 registers starting with P1.
**







|







2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
      sqlite4VdbeDestroyDecoder(pCodec);
    }
  }else{
    sqlite4VdbeMemSetNull(pDest);
  }
  UPDATE_MAX_BLOBSIZE(pDest);
  REGISTER_TRACE(pOp->p3, pDest);
  assert( rc<100 );
  break;
}

/* Opcode: Affinity P1 P2 * P4 *
**
** Apply affinities to a range of P2 registers starting with P1.
**

Changes to src/vdbecodec.c.

474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489

    /* Write the encoded key to the output buffer. */
    if( enlargeEncoderAllocation(p, pMem->n*4 + 2) ) return SQLITE4_NOMEM;
    p->aOut[p->nOut++] = 0x24;   /* Text */
    if( pColl==0 || pColl->xMkKey==0 ){
      const char *z = (const char *)sqlite4ValueText(pMem, SQLITE4_UTF8);
      if( z ){
        char *zCsr = z;
        char *zEnd = &z[pMem->n];
        while( *zCsr && zCsr<zEnd ) zCsr++;
        memcpy(p->aOut+p->nOut, z, (zCsr-z));
        p->nOut += (zCsr-z);
      }
    }else{
      int rc;                     /* xMkKey() return code */
      int nReq;                   /* Space required by xMkKey() */







|
|







474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489

    /* Write the encoded key to the output buffer. */
    if( enlargeEncoderAllocation(p, pMem->n*4 + 2) ) return SQLITE4_NOMEM;
    p->aOut[p->nOut++] = 0x24;   /* Text */
    if( pColl==0 || pColl->xMkKey==0 ){
      const char *z = (const char *)sqlite4ValueText(pMem, SQLITE4_UTF8);
      if( z ){
        const char *zCsr = z;
        const char *zEnd = &z[pMem->n];
        while( *zCsr && zCsr<zEnd ) zCsr++;
        memcpy(p->aOut+p->nOut, z, (zCsr-z));
        p->nOut += (zCsr-z);
      }
    }else{
      int rc;                     /* xMkKey() return code */
      int nReq;                   /* Space required by xMkKey() */

Changes to src/where.c.

17
18
19
20
21
22
23
24
25
26
27
28
29
30
31


32
33
34
35
36
37
38
39
40
41
42

43













































































































































44
45
46
47
48
49
50
..
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
...
123
124
125
126
127
128
129
















130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
...
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
...
201
202
203
204
205
206
207
208
209
210
211
212
213
214


215
216
217

































218

219
220

221
222
223
224
225
226
227
228
229
230
231

232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256

257
258
259
260
261
262




263
264
265
266








267





268

269
















































270
271
272
273
274
275
276

277
278
279

280
281
282
283
284
285
286
287
288
289
290
291
292
...
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
...
322
323
324
325
326
327
328



















329
330
331
332
333
334
335
...
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
...
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
...
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
...
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
...
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
...
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543





544
545
546



547


548
549
550
551
552
553
554
...
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589

590
591
592
593
594
595
596
597
598
599

600
601
602
603
604
605
606





607
608

609
610
611
612
613
614
615










616

617







618
619
620
621
622
623
624
625
626
627












































628
629















































































630
631


632







633
634
635
636
637







































638
639

640

641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
...
693
694
695
696
697
698
699

700


701
702
703
704
705
706
707
...
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
...
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
...
876
877
878
879
880
881
882
883

884
885
886
887
888
889
890
891
892
893
894
...
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
....
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
....
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
....
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
....
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
....
1129
1130
1131
1132
1133
1134
1135

1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154

1155
1156
1157
1158
1159
1160
1161
....
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182

1183
1184
1185
1186
1187
1188
1189
1190

1191
1192
1193
1194
1195
1196
1197
....
1198
1199
1200
1201
1202
1203
1204







1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
....
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
....
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314

1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
....
1377
1378
1379
1380
1381
1382
1383

1384
1385
1386
1387
1388
1389
1390
....
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
....
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473

1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536

1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
....
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573



1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584

1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608








1609
1610
1611
1612
1613
1614
1615



1616
1617



1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645


1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665




1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713

1714
1715


1716
1717

1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740





1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751




1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766



1767
1768
1769
1770
1771
1772
1773

1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801


1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
....
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966

1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076


2077

2078
2079


2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091

2092
2093
2094
2095
2096
2097
2098






2099
2100


2101
2102
2103
2104
2105
2106





















2107
2108
2109
2110
2111
2112

2113
2114
2115
2116
2117

2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129


2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141


















2142
2143
2144

2145
2146
2147
2148
2149

2150
2151
2152
2153
2154

2155

2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207

2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
....
2236
2237
2238
2239
2240
2241
2242

2243
2244

2245
2246
2247
2248
2249
2250
2251


2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
....
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
....
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
....
2311
2312
2313
2314
2315
2316
2317

2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488

2489
2490
2491
2492
2493
2494
2495


2496
2497
2498
2499
2500
2501
2502

2503










2504
2505
2506
2507










2508
2509
2510



2511


2512
2513
2514
2515
2516
2517





























































2518
2519
2520
2521
2522
2523
2524
....
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558


2559
2560
2561
2562

2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599

2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
....
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687

2688
2689
2690
2691
2692

2693
2694

2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705

2706
2707
2708

2709
2710
2711
2712
2713

2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725


2726


2727


2728
2729
2730
2731
2732
2733
2734
....
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771

2772
2773
2774
2775

2776
2777
2778

2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
....
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
....
3486
3487
3488
3489
3490
3491
3492
3493


3494
3495
3496
3497
3498
3499
3500
....
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525

3526








3527
3528




3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554




3555
3556
3557
3558

3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570

3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
....
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633

3634
3635
3636
3637
3638
3639
3640
3641




3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
....
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739


3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754


3755
3756

3757
3758
3759
3760

3761
3762
3763
3764
3765
3766
3767
3768
....
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789


3790


3791
3792
3793
3794

3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822







3823
3824
3825
3826
3827
3828

3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843

3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858

3859
3860

3861
3862
3863
3864
3865
3866
3867

3868

3869
3870
3871
3872
3873

3874
3875
3876




3877
3878
3879
3880
3881
3882
3883
....
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921


3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936

3937



3938
3939
3940

3941
3942
3943
3944
3945
3946
3947
3948
3949

3950
3951

3952
3953
3954

3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965

3966










































































































3967
3968
3969
3970
3971
3972
3973
3974
....
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
....
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061


4062
4063

4064
4065
4066
4067

4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086

4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
....
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
....
4147
4148
4149
4150
4151
4152
4153
4154
4155

4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
....
4178
4179
4180
4181
4182
4183
4184

4185
4186
4187
4188
4189
4190
4191
....
4200
4201
4202
4203
4204
4205
4206
4207
4208

4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228




4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
....
4268
4269
4270
4271
4272
4273
4274


4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336









4337
4338







4339

4340


4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355

4356

4357
4358
4359
4360
4361
4362
4363
4364
4365
4366

4367
4368
4369
4370
4371
4372
4373
4374
4375

























4376
4377
4378
4379
4380
4381




4382

4383
4384
4385
4386
4387
4388
4389
4390
4391
4392



4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431






























4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458





























































































4459


4460
4461
4462
4463
4464

4465
4466
4467









4468
4469
4470
4471
4472








4473
4474
4475
4476




























































































































































































































































































































































































4477
4478







































































































































































4479
4480










































































4481























































4482









4483

4484





4485

4486


































































































































































































































































4487
4488







































4489
4490
4491






























































































































































































































































































































4492

4493
4494






4495
4496






























4497

4498
4499





















4500





























































4501
4502
4503
4504
4505
4506
4507
....
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
....
4570
4571
4572
4573
4574
4575
4576
4577

4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596

4597
4598
4599
4600
4601
4602
4603

4604
4605
4606
4607

4608
4609
4610















4611
4612
4613
4614
4615
4616
4617
....
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649


4650
4651
4652
4653
4654
4655

4656
4657
4658




4659
4660
4661
4662
4663
4664
4665
4666

4667
4668
4669
4670
4671
4672
4673
4674









4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717




4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729





4730
4731
4732
4733
4734
4735
4736
4737
4738


4739
4740
4741
4742
4743

4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758

4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822





4823
4824
4825
4826
4827










4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845





4846
4847
4848


4849
4850
4851
4852
4853
4854


4855
4856
4857






4858




4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894



4895


4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906



4907
4908
4909
4910
4911
4912
4913













4914
4915
4916
4917
4918
4919


4920
4921
4922
4923
4924







4925
4926
4927
4928
4929
4930
4931



4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955

4956
4957
4958
4959
4960
4961
4962
4963

4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976

4977
4978
4979
4980
4981
4982

4983
4984
4985
4986
4987
4988
4989
4990


4991
4992
4993
4994
4995
4996
4997
4998








4999







5000
5001

5002
5003
5004
5005
5006
5007
5008

5009
5010

5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
....
5097
5098
5099
5100
5101
5102
5103

5104
5105
5106
5107
5108
5109
5110
5111

5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
....
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160

5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189

5190
5191

5192
5193
5194
5195
5196
5197
5198


5199



5200

5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218

5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
** indices, you might also think of this module as the "query optimizer".
*/
#include "sqliteInt.h"

/* For VdbeCodecEncodeKey() - revisit this */
#include "vdbeInt.h"


/*
** Trace output macros
*/
#if defined(SQLITE4_TEST) || defined(SQLITE4_DEBUG)
int sqlite4WhereTrace = 0;
#endif
#if defined(SQLITE4_TEST) && defined(SQLITE4_DEBUG)


# define WHERETRACE(X)  if(sqlite4WhereTrace) sqlite4DebugPrintf X
#else
# define WHERETRACE(X)
#endif

/* Forward reference
*/
typedef struct WhereClause WhereClause;
typedef struct WhereMaskSet WhereMaskSet;
typedef struct WhereOrInfo WhereOrInfo;
typedef struct WhereAndInfo WhereAndInfo;

typedef struct WhereCost WhereCost;














































































































































/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by AND operators,
** usually, or sometimes subexpressions separated by OR.
**
................................................................................
** bits in the Bitmask.  So, in the example above, the cursor numbers
** would be mapped into integers 0 through 7.
**
** The number of terms in a join is limited by the number of bits
** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
** is only able to process joins with 64 or fewer tables.
*/
typedef struct WhereTerm WhereTerm;
struct WhereTerm {
  Expr *pExpr;            /* Pointer to the subexpression that is this term */
  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
  union {
    int leftColumn;         /* Column number of X in "X <op> <expr>" */
    WhereOrInfo *pOrInfo;   /* Extra information if eOperator==WO_OR */
    WhereAndInfo *pAndInfo; /* Extra information if eOperator==WO_AND */
  } u;
  u16 eOperator;          /* A WO_xx value describing <op> */
  u8 wtFlags;             /* TERM_xxx bit flags.  See below */
  u8 nChild;              /* Number of children that must disable us */
  WhereClause *pWC;       /* The clause this term is part of */
  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */
................................................................................
#define TERM_OR_OK      0x40   /* Used during OR-clause processing */
#ifdef SQLITE4_ENABLE_STAT3
#  define TERM_VNULL    0x80   /* Manufactured x>NULL or x<=NULL term */
#else
#  define TERM_VNULL    0x00   /* Disabled if not using stat3 */
#endif

















/*
** An instance of the following structure holds all information about a
** WHERE clause.  Mostly this is a container for one or more WhereTerms.
**
** Explanation of pOuter:  For a WHERE clause of the form
**
**           a AND ((b AND c) OR (d AND e)) AND f
**
** There are separate WhereClause objects for the whole clause and for
** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
** subclauses points to the WhereClause object for the whole clause.
*/
struct WhereClause {
  Parse *pParse;           /* The parser context */
  WhereMaskSet *pMaskSet;  /* Mapping of table cursor numbers to bitmasks */
  Bitmask vmask;           /* Bitmask identifying virtual table cursors */
  WhereClause *pOuter;     /* Outer conjunction */
  u8 op;                   /* Split operator.  TK_AND or TK_OR */
  u16 wctrlFlags;          /* Might include WHERE_AND_ONLY */
  int nTerm;               /* Number of terms */
  int nSlot;               /* Number of entries in a[] */
  WhereTerm *a;            /* Each a[] describes a term of the WHERE cluase */
#if defined(SQLITE4_SMALL_STACK)
  WhereTerm aStatic[1];    /* Initial static space for a[] */
#else
  WhereTerm aStatic[8];    /* Initial static space for a[] */
................................................................................
};

/*
** An instance of the following structure keeps track of a mapping
** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
**
** The VDBE cursor numbers are small integers contained in 
** SrcList_item.iCursor and Expr.iTable fields.  For any given WHERE 
** clause, the cursor numbers might not begin with 0 and they might
** contain gaps in the numbering sequence.  But we want to make maximum
** use of the bits in our bitmasks.  This structure provides a mapping
** from the sparse cursor numbers into consecutive integers beginning
** with 0.
**
** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
................................................................................
*/
struct WhereMaskSet {
  int n;                        /* Number of assigned cursor values */
  int ix[BMS];                  /* Cursor assigned to each bit */
};

/*
** A WhereCost object records a lookup strategy and the estimated
** cost of pursuing that strategy.
*/
struct WhereCost {
  WherePlan plan;    /* The lookup strategy */
  double rCost;      /* Overall cost of pursuing this search strategy */
  Bitmask used;      /* Bitmask of cursors used by this plan */


};

/*

































** Bitmasks for the operators that indices are able to exploit.  An

** OR-ed combination of these values can be used when searching for
** terms in the where clause.

*/
#define WO_IN     0x001
#define WO_EQ     0x002
#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
#define WO_MATCH  0x040
#define WO_ISNULL 0x080
#define WO_OR     0x100       /* Two or more OR-connected terms */
#define WO_AND    0x200       /* Two or more AND-connected terms */

#define WO_NOOP   0x800       /* This term does not restrict search space */

#define WO_ALL    0xfff       /* Mask of all possible WO_* values */
#define WO_SINGLE 0x0ff       /* Mask of all non-compound WO_* values */

/*
** Value for wsFlags returned by bestIndex() and stored in
** WhereLevel.wsFlags.  These flags determine which search
** strategies are appropriate.
**
** The least significant 12 bits is reserved as a mask for WO_ values above.
** The WhereLevel.wsFlags field is usually set to WO_IN|WO_EQ|WO_ISNULL.
** But if the table is the right table of a left join, WhereLevel.wsFlags
** is set to WO_IN|WO_EQ.  The WhereLevel.wsFlags field can then be used as
** the "op" parameter to findTerm when we are resolving equality constraints.
** ISNULL constraints will then not be used on the right table of a left
** join.  Tickets #2177 and #2189.
*/
#define WHERE_COLUMN_EQ    0x00010000  /* x=EXPR or x IN (...) or x IS NULL */
#define WHERE_COLUMN_RANGE 0x00020000  /* x<EXPR and/or x>EXPR */
#define WHERE_COLUMN_IN    0x00040000  /* x IN (...) */
#define WHERE_COLUMN_NULL  0x00080000  /* x IS NULL */
#define WHERE_INDEXED      0x000f0000  /* Anything that uses an index */
#define WHERE_NOT_FULLSCAN 0x100f3000  /* Does not do a full table scan */
#define WHERE_IN_ABLE      0x000f1000  /* Able to support an IN operator */

#define WHERE_TOP_LIMIT    0x00100000  /* x<EXPR or x<=EXPR constraint */
#define WHERE_BTM_LIMIT    0x00200000  /* x>EXPR or x>=EXPR constraint */
#define WHERE_BOTH_LIMIT   0x00300000  /* Both x>EXPR and x<EXPR */
#define WHERE_IDX_ONLY     0x00800000  /* Use index only - omit table */
#define WHERE_ORDERBY      0x01000000  /* Output will appear in correct order */
#define WHERE_REVERSE      0x02000000  /* Scan in reverse order */




#define WHERE_UNIQUE       0x04000000  /* Selects no more than one row */
#define WHERE_VIRTUALTABLE 0x08000000  /* Use virtual-table processing */
#define WHERE_MULTI_OR     0x10000000  /* OR using multiple indices */
#define WHERE_TEMP_INDEX   0x20000000  /* Uses an ephemeral index */








#define WHERE_DISTINCT     0x40000000  /* Correct order for DISTINCT */







/*
















































** Initialize a preallocated WhereClause structure.
*/
static void whereClauseInit(
  WhereClause *pWC,        /* The WhereClause to be initialized */
  Parse *pParse,           /* The parsing context */
  WhereMaskSet *pMaskSet,  /* Mapping from table cursor numbers to bitmasks */
  u16 wctrlFlags           /* Might include WHERE_AND_ONLY */

){
  pWC->pParse = pParse;
  pWC->pMaskSet = pMaskSet;

  pWC->pOuter = 0;
  pWC->nTerm = 0;
  pWC->nSlot = ArraySize(pWC->aStatic);
  pWC->a = pWC->aStatic;
  pWC->vmask = 0;
  pWC->wctrlFlags = wctrlFlags;
}

/* Forward reference */
static void whereClauseClear(WhereClause*);

/*
** Deallocate all memory associated with a WhereOrInfo object.
................................................................................
/*
** Deallocate a WhereClause structure.  The WhereClause structure
** itself is not freed.  This routine is the inverse of whereClauseInit().
*/
static void whereClauseClear(WhereClause *pWC){
  int i;
  WhereTerm *a;
  sqlite4 *db = pWC->pParse->db;
  for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
    if( a->wtFlags & TERM_DYNAMIC ){
      sqlite4ExprDelete(db, a->pExpr);
    }
    if( a->wtFlags & TERM_ORINFO ){
      whereOrInfoDelete(db, a->u.pOrInfo);
    }else if( a->wtFlags & TERM_ANDINFO ){
................................................................................
      whereAndInfoDelete(db, a->u.pAndInfo);
    }
  }
  if( pWC->a!=pWC->aStatic ){
    sqlite4DbFree(db, pWC->a);
  }
}




















/*
** Add a single new WhereTerm entry to the WhereClause object pWC.
** The new WhereTerm object is constructed from Expr p and with wtFlags.
** The index in pWC->a[] of the new WhereTerm is returned on success.
** 0 is returned if the new WhereTerm could not be added due to a memory
** allocation error.  The memory allocation failure will be recorded in
................................................................................
*/
static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
  WhereTerm *pTerm;
  int idx;
  testcase( wtFlags & TERM_VIRTUAL );  /* EV: R-00211-15100 */
  if( pWC->nTerm>=pWC->nSlot ){
    WhereTerm *pOld = pWC->a;
    sqlite4 *db = pWC->pParse->db;
    pWC->a = sqlite4DbMallocRaw(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
    if( pWC->a==0 ){
      if( wtFlags & TERM_DYNAMIC ){
        sqlite4ExprDelete(db, p);
      }
      pWC->a = pOld;
      return 0;
................................................................................
    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
    if( pOld!=pWC->aStatic ){
      sqlite4DbFree(db, pOld);
    }
    pWC->nSlot = sqlite4DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
  }
  pTerm = &pWC->a[idx = pWC->nTerm++];
  pTerm->pExpr = p;
  pTerm->wtFlags = wtFlags;
  pTerm->pWC = pWC;
  pTerm->iParent = -1;
  return idx;
}

/*
................................................................................
** The original WHERE clause in pExpr is unaltered.  All this routine
** does is make slot[] entries point to substructure within pExpr.
**
** In the previous sentence and in the diagram, "slot[]" refers to
** the WhereClause.a[] array.  The slot[] array grows as needed to contain
** all terms of the WHERE clause.
*/
static void whereSplit(WhereClause *pWC, Expr *pExpr, int op){
  pWC->op = (u8)op;
  if( pExpr==0 ) return;
  if( pExpr->op!=op ){
    whereClauseInsert(pWC, pExpr, 0);
  }else{
    whereSplit(pWC, pExpr->pLeft, op);
    whereSplit(pWC, pExpr->pRight, op);
  }
}

/*
** Initialize an expression mask set (a WhereMaskSet object)
*/
#define initMaskSet(P)  memset(P, 0, sizeof(*P))

/*
** Return the bitmask for the given cursor number.  Return 0 if
** iCursor is not in the set.
*/
static Bitmask getMask(WhereMaskSet *pMaskSet, int iCursor){
  int i;
  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
  for(i=0; i<pMaskSet->n; i++){
    if( pMaskSet->ix[i]==iCursor ){
      return ((Bitmask)1)<<i;
    }
  }
  return 0;
}

/*
** Create a new mask for cursor iCursor.
................................................................................
*/
static void createMask(WhereMaskSet *pMaskSet, int iCursor){
  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
  pMaskSet->ix[pMaskSet->n++] = iCursor;
}

/*
** This routine walks (recursively) an expression tree and generates
** a bitmask indicating which tables are used in that expression
** tree.
**
** In order for this routine to work, the calling function must have
** previously invoked sqlite4ResolveExprNames() on the expression.  See
** the header comment on that routine for additional information.
** The sqlite4ResolveExprNames() routines looks for column names and
** sets their opcodes to TK_COLUMN and their Expr.iTable fields to
** the VDBE cursor number of the table.  This routine just has to
** translate the cursor numbers into bitmask values and OR all
** the bitmasks together.
*/
static Bitmask exprListTableUsage(WhereMaskSet*, ExprList*);
static Bitmask exprSelectTableUsage(WhereMaskSet*, Select*);
static Bitmask exprTableUsage(WhereMaskSet *pMaskSet, Expr *p){
  Bitmask mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
................................................................................
  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is
** allowed for an indexable WHERE clause term.  The allowed operators are
** "=", "<", ">", "<=", ">=", and "IN".
**
** IMPLEMENTATION-OF: R-59926-26393 To be usable by an index a term must be
** of one of the following forms: column = expression column > expression
** column >= expression column < expression column <= expression
** expression = column expression > column expression >= column
** expression < column expression <= column column IN
** (expression-list) column IN (subquery) column IS NULL
................................................................................
*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**
** If a collation sequence is associated with either the left or right
** side of the comparison, it remains associated with the same side after
** the commutation. So "Y collate NOCASE op X" becomes 
** "X collate NOCASE op Y". This is because any collation sequence on
** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_ExpCollate flag
** is not commuted.
*/
static void exprCommute(Parse *pParse, Expr *pExpr){
  u16 expRight = (pExpr->pRight->flags & EP_ExpCollate);
  u16 expLeft = (pExpr->pLeft->flags & EP_ExpCollate);
  assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
  pExpr->pRight->pColl = sqlite4ExprCollSeq(pParse, pExpr->pRight);





  pExpr->pLeft->pColl = sqlite4ExprCollSeq(pParse, pExpr->pLeft);
  SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl);
  pExpr->pRight->flags = (pExpr->pRight->flags & ~EP_ExpCollate) | expLeft;



  pExpr->pLeft->flags = (pExpr->pLeft->flags & ~EP_ExpCollate) | expRight;


  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
  if( pExpr->op>=TK_GT ){
    assert( TK_LT==TK_GT+2 );
    assert( TK_GE==TK_LE+2 );
    assert( TK_GT>TK_EQ );
    assert( TK_GT<TK_LE );
    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
................................................................................
  assert( op!=TK_EQ || c==WO_EQ );
  assert( op!=TK_LT || c==WO_LT );
  assert( op!=TK_LE || c==WO_LE );
  assert( op!=TK_GT || c==WO_GT );
  assert( op!=TK_GE || c==WO_GE );
  return c;
}

/*
** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
** where X is a reference to the iColumn of table iCur and <op> is one of
** the WO_xx operator codes specified by the op parameter.
** Return a pointer to the term.  Return 0 if not found.
*/
static WhereTerm *findTerm(

  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
){
  sqlite4 *db = pWC->pParse->db;  /* Database handle */
  WhereTerm *pTerm;
  int k;


  assert( iCur>=0 );
  op &= WO_ALL;
  for(; pWC; pWC=pWC->pOuter){
    for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
      if( pTerm->leftCursor==iCur
         && (pTerm->prereqRight & notReady)==0





         && pTerm->u.leftColumn==iColumn
         && (pTerm->eOperator & op)!=0

      ){
        if( iColumn>=0 && pIdx && pTerm->eOperator!=WO_ISNULL ){
          Table *pTab = pIdx->pTable;
          const char *zColl;      /* Collation sequence used by index */
          CollSeq *pColl;         /* Collation sequence used by expression */
          Expr *pX = pTerm->pExpr;
          int j;










          Parse *pParse = pWC->pParse;

  







          if( !sqlite4IndexAffinityOk(pX, pTab->aCol[iColumn].affinity) ){
            continue;
          }
  
          /* Figure out the collation sequence used by expression pX. Store
          ** this in pColl. Also the collation sequence used by the index.
          ** Store this one in zColl.  */
          assert(pX->pLeft);
          pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
          for(j=0; pIdx->aiColumn[j]!=iColumn && j<pIdx->nColumn; j++);












































          if( j>=pIdx->nColumn ){
            zColl = pTab->aCol[iColumn].zColl;















































































          }else{
            zColl = pIdx->azColl[j];


          }








          /* If the collation sequence used by the index is not the same as
          ** that used by the expression, then this term is not a match.  */
          if( pColl!=sqlite4FindCollSeq(db, zColl, 0) ) continue;
        }







































        return pTerm;
      }

    }

  }
  return 0;
}

/* Forward reference */
static void exprAnalyze(SrcList*, WhereClause*, int);

/*
** Call exprAnalyze on all terms in a WHERE clause.  
**
** Note that exprAnalyze() might add new virtual terms onto the end of 
** the WHERE clause.  We do not want to analyze these virtual terms, so 
** start analyzing at the end and work forward so that the added virtual 
** terms are never processed.
*/
static void exprAnalyzeAll(
  SrcList *pTabList,       /* the FROM clause */
  WhereClause *pWC         /* the WHERE clause to be analyzed */
){
  int i;
  for(i=pWC->nTerm-1; i>=0; i--){
................................................................................
    return 0;
  }
#ifdef SQLITE4_EBCDIC
  if( *pnoCase ) return 0;
#endif
  pList = pExpr->x.pList;
  pLeft = pList->a[1].pExpr;

  if( pLeft->op!=TK_COLUMN || sqlite4ExprAffinity(pLeft)!=SQLITE4_AFF_TEXT ){


    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
    ** be the name of an indexed column with TEXT affinity. */
    return 0;
  }
  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */

  pRight = pList->a[0].pExpr;
................................................................................
    op = pRight->op2;
  }
  if( op==TK_VARIABLE ){
    Vdbe *pReprepare = pParse->pReprepare;
    int iCol = pRight->iColumn;
    pVal = sqlite4VdbeGetValue(pReprepare, iCol, SQLITE4_AFF_NONE);
    if( pVal && sqlite4_value_type(pVal)==SQLITE4_TEXT ){
      z = sqlite4_value_text(pVal, 0);
    }
    sqlite4VdbeSetVarmask(pParse->pVdbe, iCol);
    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
  }else if( op==TK_STRING ){
    z = pRight->u.zToken;
  }
  if( z ){
................................................................................
**     (B)     x=expr1 OR expr2=x OR x=expr3
**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression.  In other words, if the term
** being analyzed is:
**
**      x = expr1  OR  expr2 = x  OR  x = expr3
**
** then create a new virtual term like this:
................................................................................
** zero.  This term is not useful for search.
*/
static void exprAnalyzeOrTerm(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the complete WHERE clause */
  int idxTerm               /* Index of the OR-term to be analyzed */
){
  Parse *pParse = pWC->pParse;            /* Parser context */

  sqlite4 *db = pParse->db;               /* Database connection */
  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */
  WhereMaskSet *pMaskSet = pWC->pMaskSet; /* Table use masks */
  int i;                                  /* Loop counters */
  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */

................................................................................
  */
  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
  assert( pExpr->op==TK_OR );
  pTerm->u.pOrInfo = pOrInfo = sqlite4DbMallocZero(db, sizeof(*pOrInfo));
  if( pOrInfo==0 ) return;
  pTerm->wtFlags |= TERM_ORINFO;
  pOrWc = &pOrInfo->wc;
  whereClauseInit(pOrWc, pWC->pParse, pMaskSet, pWC->wctrlFlags);
  whereSplit(pOrWc, pExpr, TK_OR);
  exprAnalyzeAll(pSrc, pOrWc);
  if( db->mallocFailed ) return;
  assert( pOrWc->nTerm>=2 );

  /*
  ** Compute the set of tables that might satisfy cases 1 or 2.
  */
  indexable = ~(Bitmask)0;
  chngToIN = ~(pWC->vmask);
  for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
    if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
      WhereAndInfo *pAndInfo;
      assert( pOrTerm->eOperator==0 );
      assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
      chngToIN = 0;
      pAndInfo = sqlite4DbMallocRaw(db, sizeof(*pAndInfo));
      if( pAndInfo ){
        WhereClause *pAndWC;
        WhereTerm *pAndTerm;
        int j;
        Bitmask b = 0;
        pOrTerm->u.pAndInfo = pAndInfo;
        pOrTerm->wtFlags |= TERM_ANDINFO;
        pOrTerm->eOperator = WO_AND;
        pAndWC = &pAndInfo->wc;
        whereClauseInit(pAndWC, pWC->pParse, pMaskSet, pWC->wctrlFlags);
        whereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
        exprAnalyzeAll(pSrc, pAndWC);
        pAndWC->pOuter = pWC;
        testcase( db->mallocFailed );
        if( !db->mallocFailed ){
          for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
            assert( pAndTerm->pExpr );
            if( allowedOp(pAndTerm->pExpr->op) ){
              b |= getMask(pMaskSet, pAndTerm->leftCursor);
            }
          }
        }
        indexable &= b;
      }
    }else if( pOrTerm->wtFlags & TERM_COPIED ){
      /* Skip this term for now.  We revisit it when we process the
      ** corresponding TERM_VIRTUAL term */
    }else{
      Bitmask b;
      b = getMask(pMaskSet, pOrTerm->leftCursor);
      if( pOrTerm->wtFlags & TERM_VIRTUAL ){
        WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
        b |= getMask(pMaskSet, pOther->leftCursor);
      }
      indexable &= b;
      if( pOrTerm->eOperator!=WO_EQ ){
        chngToIN = 0;
      }else{
        chngToIN &= b;
      }
    }
  }

................................................................................
    ** will be recorded in iCursor and iColumn.  There might not be any
    ** such table and column.  Set okToChngToIN if an appropriate table
    ** and column is found but leave okToChngToIN false if not found.
    */
    for(j=0; j<2 && !okToChngToIN; j++){
      pOrTerm = pOrWc->a;
      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
        assert( pOrTerm->eOperator==WO_EQ );
        pOrTerm->wtFlags &= ~TERM_OR_OK;
        if( pOrTerm->leftCursor==iCursor ){
          /* This is the 2-bit case and we are on the second iteration and
          ** current term is from the first iteration.  So skip this term. */
          assert( j==1 );
          continue;
        }
        if( (chngToIN & getMask(pMaskSet, pOrTerm->leftCursor))==0 ){
          /* This term must be of the form t1.a==t2.b where t2 is in the
          ** chngToIN set but t1 is not.  This term will be either preceeded
          ** or follwed by an inverted copy (t2.b==t1.a).  Skip this term 
          ** and use its inversion. */
          testcase( pOrTerm->wtFlags & TERM_COPIED );
          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
................................................................................
        iCursor = pOrTerm->leftCursor;
        break;
      }
      if( i<0 ){
        /* No candidate table+column was found.  This can only occur
        ** on the second iteration */
        assert( j==1 );
        assert( (chngToIN&(chngToIN-1))==0 );
        assert( chngToIN==getMask(pMaskSet, iCursor) );
        break;
      }
      testcase( j==1 );

      /* We have found a candidate table and column.  Check to see if that
      ** table and column is common to every term in the OR clause */
      okToChngToIN = 1;
      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
        assert( pOrTerm->eOperator==WO_EQ );
        if( pOrTerm->leftCursor!=iCursor ){
          pOrTerm->wtFlags &= ~TERM_OR_OK;
        }else if( pOrTerm->u.leftColumn!=iColumn ){
          okToChngToIN = 0;
        }else{
          int affLeft, affRight;
          /* If the right-hand side is also a column, then the affinities
................................................................................
      Expr *pDup;            /* A transient duplicate expression */
      ExprList *pList = 0;   /* The RHS of the IN operator */
      Expr *pLeft = 0;       /* The LHS of the IN operator */
      Expr *pNew;            /* The complete IN operator */

      for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
        if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
        assert( pOrTerm->eOperator==WO_EQ );
        assert( pOrTerm->leftCursor==iCursor );
        assert( pOrTerm->u.leftColumn==iColumn );
        pDup = sqlite4ExprDup(db, pOrTerm->pExpr->pRight, 0);
        pList = sqlite4ExprListAppend(pWC->pParse, pList, pDup);
        pLeft = pOrTerm->pExpr->pLeft;
      }
      assert( pLeft!=0 );
      pDup = sqlite4ExprDup(db, pLeft, 0);
      pNew = sqlite4PExpr(pParse, TK_IN, pDup, 0, 0);
      if( pNew ){
        int idxNew;
................................................................................
      }
      pTerm->eOperator = WO_NOOP;  /* case 1 trumps case 2 */
    }
  }
}
#endif /* !SQLITE4_OMIT_OR_OPTIMIZATION && !SQLITE4_OMIT_SUBQUERY */


/*
** The input to this routine is an WhereTerm structure with only the
** "pExpr" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the WhereTerm
** structure.
**
** If the expression is of the form "<expr> <op> X" it gets commuted
................................................................................
** and the copy has idxParent set to the index of the original term.
*/
static void exprAnalyze(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the WHERE clause */
  int idxTerm               /* Index of the term to be analyzed */
){

  WhereTerm *pTerm;                /* The term to be analyzed */
  WhereMaskSet *pMaskSet;          /* Set of table index masks */
  Expr *pExpr;                     /* The expression to be analyzed */
  Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
  Bitmask prereqAll;               /* Prerequesites of pExpr */
  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
  int noCase = 0;                  /* LIKE/GLOB distinguishes case */
  int op;                          /* Top-level operator.  pExpr->op */
  Parse *pParse = pWC->pParse;     /* Parsing context */
  sqlite4 *db = pParse->db;        /* Database connection */

  if( db->mallocFailed ){
    return;
  }
  pTerm = &pWC->a[idxTerm];
  pMaskSet = pWC->pMaskSet;
  pExpr = pTerm->pExpr;

  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
    }else{
................................................................................
    extraRight = x-1;  /* ON clause terms may not be used with an index
                       ** on left table of a LEFT JOIN.  Ticket #3015 */
  }
  pTerm->prereqAll = prereqAll;
  pTerm->leftCursor = -1;
  pTerm->iParent = -1;
  pTerm->eOperator = 0;
  if( allowedOp(op) && (pTerm->prereqRight & prereqLeft)==0 ){
    Expr *pLeft = pExpr->pLeft;
    Expr *pRight = pExpr->pRight;

    if( pLeft->op==TK_COLUMN ){
      pTerm->leftCursor = pLeft->iTable;
      pTerm->u.leftColumn = pLeft->iColumn;
      pTerm->eOperator = operatorMask(op);
    }
    if( pRight && pRight->op==TK_COLUMN ){
      WhereTerm *pNew;
      Expr *pDup;

      if( pTerm->leftCursor>=0 ){
        int idxNew;
        pDup = sqlite4ExprDup(db, pExpr, 0);
        if( db->mallocFailed ){
          sqlite4ExprDelete(db, pDup);
          return;
        }
................................................................................
        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
        if( idxNew==0 ) return;
        pNew = &pWC->a[idxNew];
        pNew->iParent = idxTerm;
        pTerm = &pWC->a[idxTerm];
        pTerm->nChild = 1;
        pTerm->wtFlags |= TERM_COPIED;







      }else{
        pDup = pExpr;
        pNew = pTerm;
      }
      exprCommute(pParse, pDup);
      pLeft = pDup->pLeft;
      pNew->leftCursor = pLeft->iTable;
      pNew->u.leftColumn = pLeft->iColumn;
      testcase( (prereqLeft | extraRight) != prereqLeft );
      pNew->prereqRight = prereqLeft | extraRight;
      pNew->prereqAll = prereqAll;
      pNew->eOperator = operatorMask(pDup->op);
    }
  }

#ifndef SQLITE4_OMIT_BETWEEN_OPTIMIZATION
  /* If a term is the BETWEEN operator, create two new virtual terms
  ** that define the range that the BETWEEN implements.  For example:
  **
................................................................................
  ){
    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
    Expr *pNewExpr1;
    Expr *pNewExpr2;
    int idxNew1;
    int idxNew2;
    CollSeq *pColl;    /* Collating sequence to use */

    pLeft = pExpr->x.pList->a[1].pExpr;
    pStr2 = sqlite4ExprDup(db, pStr1, 0);
    if( !db->mallocFailed ){
      u8 c, *pC;       /* Last character before the first wildcard */
      pC = (u8*)&pStr2->u.zToken[sqlite4Strlen30(pStr2->u.zToken)-1];
      c = *pC;
................................................................................
        if( c=='A'-1 ) isComplete = 0;   /* EV: R-64339-08207 */


        c = sqlite4UpperToLower[c];
      }
      *pC = c + 1;
    }
    pColl = sqlite4FindCollSeq(db, noCase ? "NOCASE" : "BINARY",0);
    pNewExpr1 = sqlite4PExpr(pParse, TK_GE, 
                     sqlite4ExprSetColl(sqlite4ExprDup(db,pLeft,0), pColl),
                     pStr1, 0);

    idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew1==0 );
    exprAnalyze(pSrc, pWC, idxNew1);
    pNewExpr2 = sqlite4PExpr(pParse, TK_LT,
                     sqlite4ExprSetColl(sqlite4ExprDup(db,pLeft,0), pColl),
                     pStr2, 0);
    idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew2==0 );
    exprAnalyze(pSrc, pWC, idxNew2);
    pTerm = &pWC->a[idxTerm];
    if( isComplete ){
      pWC->a[idxNew1].iParent = idxTerm;
      pWC->a[idxNew2].iParent = idxTerm;
................................................................................
  ** TERM_VNULL tag will suppress the not-null check at the beginning
  ** of the loop.  Without the TERM_VNULL flag, the not-null check at
  ** the start of the loop will prevent any results from being returned.
  */
  if( pExpr->op==TK_NOTNULL
   && pExpr->pLeft->op==TK_COLUMN
   && pExpr->pLeft->iColumn>=0

  ){
    Expr *pNewExpr;
    Expr *pLeft = pExpr->pLeft;
    int idxNew;
    WhereTerm *pNewTerm;

    pNewExpr = sqlite4PExpr(pParse, TK_GT,
................................................................................
  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
  ** an index for tables to the left of the join.
  */
  pTerm->prereqRight |= extraRight;
}

/*
** Return TRUE if any of the expressions in pList->a[iFirst...] contain
** a reference to any table other than the iBase table.
*/
static int referencesOtherTables(
  ExprList *pList,          /* Search expressions in ths list */
  WhereMaskSet *pMaskSet,   /* Mapping from tables to bitmaps */
  int iFirst,               /* Be searching with the iFirst-th expression */
  int iBase                 /* Ignore references to this table */
){
  Bitmask allowed = ~getMask(pMaskSet, iBase);
  while( iFirst<pList->nExpr ){
    if( (exprTableUsage(pMaskSet, pList->a[iFirst++].pExpr)&allowed)!=0 ){
      return 1;
    }
  }
  return 0;
}

/*
** This function searches the expression list passed as the second argument
** for an expression of type TK_COLUMN that refers to the same column and
** uses the same collation sequence as the iCol'th column of index pIdx.
** Argument iBase is the cursor number used for the table that pIdx refers
** to.
**
** If such an expression is found, its index in pList->a[] is returned. If
** no expression is found, -1 is returned.
*/
static int findIndexCol(
  Parse *pParse,                  /* Parse context */
  ExprList *pList,                /* Expression list to search */
................................................................................
  Index *pIdx,                    /* Index to match column of */
  int iCol                        /* Column of index to match */
){
  int i;
  const char *zColl = pIdx->azColl[iCol];

  for(i=0; i<pList->nExpr; i++){
    Expr *p = pList->a[i].pExpr;
    if( p->op==TK_COLUMN
     && p->iColumn==pIdx->aiColumn[iCol]
     && p->iTable==iBase
    ){
      CollSeq *pColl = sqlite4ExprCollSeq(pParse, p);
      assert( pColl || p->iColumn==-1 );
      if( 0==pColl || 0==sqlite4_stricmp(pColl->zName, zColl) ){
        return i;
      }
    }
  }

  return -1;
}

/*

** This routine determines if pIdx can be used to assist in processing a
** DISTINCT qualifier. In other words, it tests whether or not using this
** index for the outer loop guarantees that rows with equal values for
** all expressions in the pDistinct list are delivered grouped together.
**
** For example, the query 
**
**   SELECT DISTINCT a, b, c FROM tbl WHERE a = ?
**
** can benefit from any index on columns "b" and "c".
*/
static int isDistinctIndex(
  Parse *pParse,                  /* Parsing context */
  WhereClause *pWC,               /* The WHERE clause */
  Index *pIdx,                    /* The index being considered */
  int base,                       /* Cursor number for the table pIdx is on */
  ExprList *pDistinct,            /* The DISTINCT expressions */
  int nEqCol                      /* Number of index columns with == */
){
  Bitmask mask = 0;               /* Mask of unaccounted for pDistinct exprs */
  int i;                          /* Iterator variable */

  if( pIdx->zName==0 || pDistinct==0 || pDistinct->nExpr>=BMS ) return 0;
  testcase( pDistinct->nExpr==BMS-1 );

  /* Loop through all the expressions in the distinct list. If any of them
  ** are not simple column references, return early. Otherwise, test if the
  ** WHERE clause contains a "col=X" clause. If it does, the expression
  ** can be ignored. If it does not, and the column does not belong to the
  ** same table as index pIdx, return early. Finally, if there is no
  ** matching "col=X" expression and the column is on the same table as pIdx,
  ** set the corresponding bit in variable mask.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    WhereTerm *pTerm;
    Expr *p = pDistinct->a[i].pExpr;
    if( p->op!=TK_COLUMN ) return 0;
    pTerm = findTerm(pWC, p->iTable, p->iColumn, ~(Bitmask)0, WO_EQ, 0);
    if( pTerm ){
      Expr *pX = pTerm->pExpr;
      CollSeq *p1 = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
      CollSeq *p2 = sqlite4ExprCollSeq(pParse, p);
      if( p1==p2 ) continue;
    }
    if( p->iTable!=base ) return 0;
    mask |= (((Bitmask)1) << i);
  }

  for(i=nEqCol; mask && i<pIdx->nColumn; i++){
    int iExpr = findIndexCol(pParse, pDistinct, base, pIdx, i);
    if( iExpr<0 ) break;
    mask &= ~(((Bitmask)1) << iExpr);
  }

  return (mask==0);
}


/*
** Return true if the DISTINCT expression-list passed as the third argument
** is redundant. A DISTINCT list is redundant if the database contains a
** UNIQUE index that guarantees that the result of the query will be distinct
** anyway.

*/
static int isDistinctRedundant(
  Parse *pParse,
  SrcList *pTabList,
  WhereClause *pWC,
  ExprList *pDistinct
){
  Table *pTab;
  Index *pIdx;
  int i;                          
  int iBase;

  /* If there is more than one table or sub-select in the FROM clause of
................................................................................
  pTab = pTabList->a[0].pTab;

  /* If any of the expressions is an IPK column on table iBase, then return 
  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
  ** current SELECT is a correlated sub-query.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    Expr *p = pDistinct->a[i].pExpr;
    if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
  }

  /* Loop through all indices on the table, checking each to see if it makes
  ** the DISTINCT qualifier redundant. It does so if:
  **
  **   1. The index is itself UNIQUE, and
  **
  **   2. All of the columns in the index are either part of the pDistinct
  **      list, or else the WHERE clause contains a term of the form "col=X",
  **      where X is a constant value. The collation sequences of the
  **      comparison and select-list expressions must match those of the index.



  */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    if( pIdx->onError==OE_None ) continue;
    for(i=0; i<pIdx->nColumn; i++){
      int iCol = pIdx->aiColumn[i];
      if( 0==findTerm(pWC, iBase, iCol, ~(Bitmask)0, WO_EQ, pIdx) 
       && 0>findIndexCol(pParse, pDistinct, iBase, pIdx, i)
      ){
        break;
      }
    }

    if( i==pIdx->nColumn ){
      /* This index implies that the DISTINCT qualifier is redundant. */
      return 1;
    }
  }

  return 0;
}


/*
** Return the table column number of the iIdxCol'th field in the index
** keys used by index pIdx, including any appended PRIMARY KEY fields.
** If there is no iIdxCol'th field in index pIdx, return -2.
**
** Example:
**
**   CREATE TABLE t1(a, b, c, PRIMARY KEY(a, b));
**   CREATE INDEX i1 ON t1(c);
**
** Index i1 in the example above consists of three fields - the indexed
** field "c" followed by the two primary key fields. The automatic PRIMARY
** KEY index consists of two fields only.
*/








static int idxColumnNumber(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = -2;
  if( iIdxCol<pIdx->nColumn ){
    iRet = pIdx->aiColumn[iIdxCol];
  }else if( pPk && iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    iRet = pPk->aiColumn[iIdxCol - pIdx->nColumn];
  }



  return iRet;
}




/*
** Return the name of the iCol'th column of table pTab. Or, if iCol is less
** than zero, return a pointer to the constant string "rowid".
*/
static const char *tblColumnName(Table *pTab, int iCol){
  if( iCol<0 ) return "rowid";
  return pTab->aCol[iCol].zName;
}

/*
** This routine decides if pIdx can be used to satisfy the ORDER BY
** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
** ORDER BY clause, this routine returns 0.
**
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
** the table has a cursor number of "base".  pIdx is an index on pTab.
**
** nEqCol is the number of columns of pIdx that are used as equality
** constraints.  Any of these columns may be missing from the ORDER BY
** clause and the match can still be a success.
**
** All terms of the ORDER BY that match against the index must be either
** ASC or DESC.  (Terms of the ORDER BY clause past the end of a UNIQUE
** index do not need to satisfy this constraint.)  The *pbRev value is
** set to 1 if the ORDER BY clause is all DESC and it is set to 0 if
** the ORDER BY clause is all ASC.


*/
static int isSortingIndex(
  Parse *pParse,          /* Parsing context */
  WhereMaskSet *pMaskSet, /* Mapping from table cursor numbers to bitmaps */
  Index *pIdx,            /* The index we are testing */
  int base,               /* Cursor number for the table to be sorted */
  ExprList *pOrderBy,     /* The ORDER BY clause */
  int nEqCol,             /* Number of index columns with == constraints */
  int wsFlags,            /* Index usages flags */
  int *pbRev              /* Set to 1 if ORDER BY is DESC */
){
  sqlite4 *db = pParse->db;       /* Database handle */
  int sortOrder = 0;              /* XOR of index and ORDER BY sort direction */
  int nTerm;                      /* Number of ORDER BY terms */
  int iTerm;                      /* Used to iterate through nTerm terms */
  int iNext = nEqCol;             /* Index of next unmatched column in index */
  int nIdxCol;                    /* Number of columns in index, incl. PK */
  Index *pPk;
  Table *pTab;





  if( !pOrderBy ) return 0;
  if( wsFlags & WHERE_COLUMN_IN ) return 0;
  if( pIdx->fIndex & IDX_Unordered ) return 0;

  pTab = pIdx->pTable;
  pPk = sqlite4FindPrimaryKey(pTab, 0);
  nTerm = pOrderBy->nExpr;
  nIdxCol = pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn);

  assert( nTerm>0 );
  assert( pIdx && pIdx->zName );

  for(iTerm=0; iTerm<nTerm; iTerm++){
    ExprListItem *pTerm;  /* iTerm'th term of ORDER BY clause */
    int iIdxCol;                  /* Index of column in index records */

    Expr *pExpr;       /* The expression of the ORDER BY pTerm */
    CollSeq *pColl;    /* The collating sequence of pExpr */
    int iColumn;       /* The i-th column of the index.  -1 for rowid */
    const char *zColl; /* Name of the collating sequence for i-th index term */

    /* Can not use an index sort on anything that is not a column in the
    ** left-most table of the FROM clause. Break out of the loop if this
    ** expression is anything other than that. */
    pTerm = &pOrderBy->a[iTerm];
    pExpr = pTerm->pExpr;
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ) break;
    iColumn = pExpr->iColumn;

    /* Check that column iColumn is a part of the index. If it is not, then
    ** this index may not be used as a sorting index. This block also checks
    ** that column iColumn is either the iNext'th column of the index, or
    ** else one of the nEqCol columns that the index guarantees will be 
    ** constant.  */
    for(iIdxCol=0; iIdxCol<nIdxCol; iIdxCol++){
      if( idxColumnNumber(pIdx, pPk, iIdxCol)==iColumn ) break;
    }
    if( iIdxCol==nIdxCol || (iIdxCol>=nEqCol && iIdxCol!=iNext) ) break;

    /* Check that the collation sequence used by the expression is the same
    ** as the collation sequence used by the index. If not, this is not a
    ** sorting index.  */
    pColl = sqlite4ExprCollSeq(pParse, pExpr);
    if( !pColl ) pColl = db->pDfltColl;
    if( iIdxCol<pIdx->nColumn ){
      zColl = pIdx->azColl[iIdxCol];
    }else if( iColumn>=0 ) {
      zColl = pTab->aCol[iColumn].zColl;

    }else{
      zColl = 0;


    }
    if( pColl!=sqlite4FindCollSeq(db, zColl, 0) ) break;


    if( iIdxCol==iNext ){
      u8 reqSortOrder;
      u8 idxSortOrder = SQLITE4_SO_ASC;
      if( iIdxCol<pIdx->nColumn ) idxSortOrder = pIdx->aSortOrder[iIdxCol];
      assert( idxSortOrder==SQLITE4_SO_ASC || idxSortOrder==SQLITE4_SO_DESC );

      reqSortOrder = (idxSortOrder ^ pTerm->sortOrder);
      if( iNext==nEqCol ){
        sortOrder = reqSortOrder;
      }else if( sortOrder!=reqSortOrder ){
        break;
      }
      iNext++;
    }

#if 0
    if( iColumn<0 && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
      /* If the indexed column is the primary key and everything matches
      ** so far and none of the ORDER BY terms to the right reference other
      ** tables in the join, then we are assured that the index can be used 
      ** to sort because the primary key is unique and so none of the other
      ** columns will make any difference





      */
      j = nTerm;
    }
#endif
  }

  *pbRev = sortOrder!=0;

  if( iTerm>=nTerm ){
    /* All terms of the ORDER BY clause are covered by this index. The
    ** index can therefore be used for sorting.  */




    return 1;
  }

  if( pIdx->onError!=OE_None
   && iNext>=pIdx->nColumn 
   && (wsFlags & WHERE_COLUMN_NULL)==0
   && !referencesOtherTables(pOrderBy, pMaskSet, iTerm, base) 
  ){

    if( iNext==nIdxCol ){
      /* All columns indexed by this UNIQUE index, and all PK columns are
      ** are matched by a prefix of the ORDER BY clause. And since the PK
      ** columns are guaranteed to be unique and NOT NULL, there is no way
      ** for the trailing ORDER BY terms to affect the sort order. Therefore,
      ** we have a sorting index.  */



      return 1;
    }else{
      int i;
      for(i=nEqCol; i<pIdx->nColumn; i++){
        int iCol = pIdx->aiColumn[i];
        if( iCol>=0 && pTab->aCol[iCol].notNull==0 ) break;
      }


      /* All columns indexed by this UNIQUE index are matched by a prefix
      ** of the ORDER BY clause. And there is reason to believe that none
      ** of the expressions in the ORDER BY prefix will evalulate to NULL.
      ** The index may be used for sorting in this case too since it is
      ** guaranteed that none of the trailing, unmatched ORDER BY terms 
      ** affect the sort order.  */
      return (i>=pIdx->nColumn);
    }
  }

  return 0;
}

/*
** Prepare a crude estimate of the logarithm of the input value.
** The results need not be exact.  This is only used for estimating
** the total cost of performing operations with O(logN) or O(NlogN)
** complexity.  Because N is just a guess, it is no great tragedy if
** logN is a little off.
*/
static double estLog(double N){
  double logN = 1;
  double x = 10;
  while( N>x ){
    logN += 1;
    x *= 10;
  }


  return logN;
}

/*
** Two routines for printing the content of an sqlite4_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE4_TEST or SQLITE4_DEBUG are defined, then these routines
** are no-ops.
*/
#if !defined(SQLITE4_OMIT_VIRTUALTABLE) && defined(SQLITE4_DEBUG)
static void TRACE_IDX_INPUTS(sqlite4_index_info *p){
  int i;
  if( !sqlite4WhereTrace ) return;
  for(i=0; i<p->nConstraint; i++){
    sqlite4DebugPrintf("  constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
       i,
       p->aConstraint[i].iColumn,
................................................................................
  sqlite4DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
}
#else
#define TRACE_IDX_INPUTS(A)
#define TRACE_IDX_OUTPUTS(A)
#endif

/* 
** Required because bestIndex() is called by bestOrClauseIndex() 
*/
static void bestIndex(
    Parse*, WhereClause*, SrcListItem*,
    Bitmask, Bitmask, ExprList*, WhereCost*);

/*
** This routine attempts to find an scanning strategy that can be used 
** to optimize an 'OR' expression that is part of a WHERE clause. 
**
** The table associated with FROM clause term pSrc may be either a
** regular B-Tree table or a virtual table.
*/
static void bestOrClauseIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors not available for indexing */
  Bitmask notValid,           /* Cursors not available for any purpose */
  ExprList *pOrderBy,         /* The ORDER BY clause */
  WhereCost *pCost            /* Lowest cost query plan */
){
#ifndef SQLITE4_OMIT_OR_OPTIMIZATION
  const int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
  const Bitmask maskSrc = getMask(pWC->pMaskSet, iCur);  /* Bitmask for pSrc */
  WhereTerm * const pWCEnd = &pWC->a[pWC->nTerm];        /* End of pWC->a[] */
  WhereTerm *pTerm;                 /* A single term of the WHERE clause */

  /* The OR-clause optimization is disallowed if the INDEXED BY or
  ** NOT INDEXED clauses are used or if the WHERE_AND_ONLY bit is set. */
  if( pSrc->notIndexed || pSrc->pIndex!=0 ){
    return;
  }
  if( pWC->wctrlFlags & WHERE_AND_ONLY ){
    return;
  }

  /* Search the WHERE clause terms for a usable WO_OR term. */
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( pTerm->eOperator==WO_OR 
     && ((pTerm->prereqAll & ~maskSrc) & notReady)==0
     && (pTerm->u.pOrInfo->indexable & maskSrc)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      int flags = WHERE_MULTI_OR;
      double rTotal = 0;
      double nRow = 0;
      Bitmask used = 0;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
        WhereCost sTermCost;
        WHERETRACE(("... Multi-index OR testing for term %d of %d....\n", 
          (pOrTerm - pOrWC->a), (pTerm - pWC->a)
        ));
        if( pOrTerm->eOperator==WO_AND ){
          WhereClause *pAndWC = &pOrTerm->u.pAndInfo->wc;
          bestIndex(pParse, pAndWC, pSrc, notReady, notValid, 0, &sTermCost);
        }else if( pOrTerm->leftCursor==iCur ){
          WhereClause tempWC;
          tempWC.pParse = pWC->pParse;
          tempWC.pMaskSet = pWC->pMaskSet;
          tempWC.pOuter = pWC;
          tempWC.op = TK_AND;
          tempWC.a = pOrTerm;
          tempWC.wctrlFlags = 0;
          tempWC.nTerm = 1;
          bestIndex(pParse, &tempWC, pSrc, notReady, notValid, 0, &sTermCost);
        }else{
          continue;
        }
        rTotal += sTermCost.rCost;
        nRow += sTermCost.plan.nRow;
        used |= sTermCost.used;
        if( rTotal>=pCost->rCost ) break;
      }

      /* If there is an ORDER BY clause, increase the scan cost to account 
      ** for the cost of the sort. */
      if( pOrderBy!=0 ){
        WHERETRACE(("... sorting increases OR cost %.9g to %.9g\n",
                    rTotal, rTotal+nRow*estLog(nRow)));
        rTotal += nRow*estLog(nRow);
      }

      /* If the cost of scanning using this OR term for optimization is
      ** less than the current cost stored in pCost, replace the contents
      ** of pCost. */
      WHERETRACE(("... multi-index OR cost=%.9g nrow=%.9g\n", rTotal, nRow));
      if( rTotal<pCost->rCost ){
        pCost->rCost = rTotal;
        pCost->used = used;
        pCost->plan.nRow = nRow;
        pCost->plan.wsFlags = flags;
        pCost->plan.u.pTerm = pTerm;
      }
    }
  }
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */
}

#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** Return TRUE if the WHERE clause term pTerm is of a form where it
** could be used with an index to access pSrc, assuming an appropriate
** index existed.
*/
static int termCanDriveIndex(
  WhereTerm *pTerm,              /* WHERE clause term to check */
  SrcListItem *pSrc,     /* Table we are trying to access */
  Bitmask notReady               /* Tables in outer loops of the join */
){
  char aff;
  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
  if( pTerm->eOperator!=WO_EQ ) return 0;
  if( (pTerm->prereqRight & notReady)!=0 ) return 0;

  aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity;
  if( !sqlite4IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
  return 1;
}
#endif

#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** If the query plan for pSrc specified in pCost is a full table scan
** and indexing is allows (if there is no NOT INDEXED clause) and it
** possible to construct a transient index that would perform better
** than a full table scan even when the cost of constructing the index
** is taken into account, then alter the query plan to use the
** transient index.
*/
static void bestAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors that are not available */
  WhereCost *pCost            /* Lowest cost query plan */
){
  double nTableRow;           /* Rows in the input table */
  double logN;                /* log(nTableRow) */
  double costTempIdx;         /* per-query cost of the transient index */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  Table *pTable;              /* Table tht might be indexed */

  if( pParse->nQueryLoop<=(double)1 ){
    /* There is no point in building an automatic index for a single scan */
    return;
  }
  if( (pParse->db->flags & SQLITE4_AutoIndex)==0 ){
    /* Automatic indices are disabled at run-time */
    return;
  }
  if( (pWC->wctrlFlags & WHERE_NO_AUTOINDEX)!=0 ){
    return;
  }
  if( (pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)!=0 ){
    /* We already have some kind of index in use for this query. */
    return;
  }
  if( pSrc->notIndexed ){
    /* The NOT INDEXED clause appears in the SQL. */
    return;
  }
  if( pSrc->isCorrelated ){
    /* The source is a correlated sub-query. No point in indexing it. */
    return;
  }

  assert( pParse->nQueryLoop >= (double)1 );
  pTable = pSrc->pTab;
  nTableRow = pTable->nRowEst;
  logN = estLog(nTableRow);
  costTempIdx = 2*logN*(nTableRow/pParse->nQueryLoop + 1);
  if( costTempIdx>=pCost->rCost ){
    /* The cost of creating the transient table would be greater than
    ** doing the full table scan */
    return;
  }

  /* Search for any equality comparison term */
  pWCEnd = &pWC->a[pWC->nTerm];
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      WHERETRACE(("auto-index reduces cost from %.1f to %.1f\n",
                    pCost->rCost, costTempIdx));
      pCost->rCost = costTempIdx;
      pCost->plan.nRow = logN + 1;
      pCost->plan.wsFlags = WHERE_TEMP_INDEX;
      pCost->plan.u.pIdx = 0;
      pCost->used = pTerm->prereqRight;
      break;
    }
  }
}
#else
# define bestAutomaticIndex(A,B,C,D,E)  /* no-op */
#endif /* SQLITE4_OMIT_AUTOMATIC_INDEX */


#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** Generate code to construct the Index object for an automatic index
** and to set up the WhereLevel object pLevel so that the code generator
** makes use of the automatic index.
*/
static void constructAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to get the next index */
  Bitmask notReady,           /* Mask of cursors that are not available */
  WhereLevel *pLevel          /* Write new index here */
){
  int nCol = 0;               /* Number of columns in index keys */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  int nByte;                  /* Byte of memory needed for pIdx */
  Index *pIdx;                /* Object describing the transient index */
  Vdbe *v;                    /* Prepared statement under construction */
  int addrOnce;               /* Address of the initialization bypass jump */
  Table *pTable;              /* The table being indexed */
  KeyInfo *pKeyinfo;          /* Key information for the index */   
  int addrRewind;             /* Top of the index fill loop */
  int regRecord;              /* Register holding an index record */
  int regKey;                 /* Register holding an index key */
  int n;                      /* Column counter */


  CollSeq *pColl;             /* Collating sequence to on a column */

  Bitmask idxCols;            /* Bitmap of columns used for indexing */
  int iPkCur = pLevel->iTabCur;   /* Primary key cursor to read data from */



  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  addrOnce = sqlite4CodeOnce(pParse);

  /* Count the number of columns that will be encoded into the index keys.
  ** set nCol to this value. Use the idxCols mask to ensure that the same
  ** column is not added to the index more than once.  */
  pTable = pSrc->pTab;
  pWCEnd = &pWC->a[pWC->nTerm];

  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;
      testcase( iCol==BMS );
      testcase( iCol==BMS-1 );






      if( (idxCols & cMask)==0 ){
        nCol++;


        idxCols |= cMask;
      }
    }
  }
  assert( nCol>0 );
  pLevel->plan.nEq = nCol;





















  pLevel->plan.wsFlags |= WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WO_EQ;

  /* Construct the Index object to describe this index */
  nByte = sizeof(Index);          /* Index */
  nByte += nCol*sizeof(int);      /* Index.aiColumn */
  nByte += nCol*sizeof(char*);    /* Index.azColl */

  nByte += nCol;                  /* Index.aSortOrder */
  pIdx = sqlite4DbMallocZero(pParse->db, nByte);
  if( pIdx==0 ) return;
  pLevel->plan.u.pIdx = pIdx;
  pIdx->eIndexType = SQLITE4_INDEX_TEMP;

  pIdx->azColl = (char**)&pIdx[1];
  pIdx->aiColumn = (int*)&pIdx->azColl[nCol];
  pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nCol];
  pIdx->zName = "auto-index";
  pIdx->nColumn = nCol;
  pIdx->pTable = pTable;
  n = 0;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;


      if( (idxCols & cMask)==0 ){
        Expr *pX = pTerm->pExpr;
        idxCols |= cMask;
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
        pIdx->azColl[n] = ALWAYS(pColl) ? pColl->zName : "BINARY";
        n++;
      }
    }
  }
  assert( (u32)n==pLevel->plan.nEq );



















  /* Open the automatic index cursor */
  pKeyinfo = sqlite4IndexKeyinfo(pParse, pIdx);
  assert( pLevel->iIdxCur>=0 );

  sqlite4VdbeAddOp3(v, OP_OpenAutoindex, pLevel->iIdxCur, 0, 0);
  sqlite4VdbeChangeP4(v, -1, (char*)pKeyinfo, P4_KEYINFO_HANDOFF);
  VdbeComment((v, "for %s", pTable->zName));

  /* Populate the automatic index */

  regRecord = sqlite4GetTempRange(pParse, 2);
  regKey = regRecord+1;
  addrRewind = sqlite4VdbeAddOp1(v, OP_Rewind, iPkCur);
  sqlite4EncodeIndexKey(pParse, 0, iPkCur, pIdx, pLevel->iIdxCur, 1, regKey);
  sqlite4VdbeAddOp2(v, OP_RowData, iPkCur, regRecord);

  sqlite4VdbeAddOp3(v, OP_IdxInsert, pLevel->iIdxCur, regRecord, regKey);

  sqlite4VdbeAddOp2(v, OP_Next, iPkCur, addrRewind+1);
  sqlite4VdbeChangeP5(v, SQLITE4_STMTSTATUS_AUTOINDEX);
  sqlite4VdbeJumpHere(v, addrRewind);
  sqlite4ReleaseTempRange(pParse, regRecord, 2);
  
  /* Jump here when skipping the initialization */
  sqlite4VdbeJumpHere(v, addrOnce);
}
#endif /* SQLITE4_OMIT_AUTOMATIC_INDEX */

#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Allocate and populate an sqlite4_index_info structure. It is the 
** responsibility of the caller to eventually release the structure
** by passing the pointer returned by this function to sqlite4_free().
*/
static sqlite4_index_info *allocateIndexInfo(
  Parse *pParse, 
  WhereClause *pWC,
  SrcListItem *pSrc,
  ExprList *pOrderBy
){
  int i, j;
  int nTerm;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_orderby *pIdxOrderBy;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int nOrderBy;
  sqlite4_index_info *pIdxInfo;

  WHERETRACE(("Recomputing index info for %s...\n", pSrc->pTab->zName));

  /* Count the number of possible WHERE clause constraints referring
  ** to this virtual table */
  for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
    testcase( pTerm->eOperator==WO_IN );
    testcase( pTerm->eOperator==WO_ISNULL );
    if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    nTerm++;
  }

  /* If the ORDER BY clause contains only columns in the current 
  ** virtual table then allocate space for the aOrderBy part of
  ** the sqlite4_index_info structure.
  */
  nOrderBy = 0;
  if( pOrderBy ){
    for(i=0; i<pOrderBy->nExpr; i++){

      Expr *pExpr = pOrderBy->a[i].pExpr;
      if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
    }
    if( i==pOrderBy->nExpr ){
      nOrderBy = pOrderBy->nExpr;
    }
  }

  /* Allocate the sqlite4_index_info structure
  */
  pIdxInfo = sqlite4DbMallocZero(pParse->db, sizeof(*pIdxInfo)
                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
                           + sizeof(*pIdxOrderBy)*nOrderBy );
  if( pIdxInfo==0 ){
    sqlite4ErrorMsg(pParse, "out of memory");
    /* (double)0 In case of SQLITE4_OMIT_FLOATING_POINT... */
    return 0;
  }

  /* Initialize the structure.  The sqlite4_index_info structure contains
  ** many fields that are declared "const" to prevent xBestIndex from
  ** changing them.  We have to do some funky casting in order to
  ** initialize those fields.
................................................................................
  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
  *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
  *(struct sqlite4_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
  *(struct sqlite4_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
                                                                   pUsage;

  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){

    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );

    testcase( pTerm->eOperator==WO_IN );
    testcase( pTerm->eOperator==WO_ISNULL );
    if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    pIdxCons[j].iColumn = pTerm->u.leftColumn;
    pIdxCons[j].iTermOffset = i;
    pIdxCons[j].op = (u8)pTerm->eOperator;


    /* The direct assignment in the previous line is possible only because
    ** the WO_ and SQLITE4_INDEX_CONSTRAINT_ codes are identical.  The
    ** following asserts verify this fact. */
    assert( WO_EQ==SQLITE4_INDEX_CONSTRAINT_EQ );
    assert( WO_LT==SQLITE4_INDEX_CONSTRAINT_LT );
    assert( WO_LE==SQLITE4_INDEX_CONSTRAINT_LE );
    assert( WO_GT==SQLITE4_INDEX_CONSTRAINT_GT );
    assert( WO_GE==SQLITE4_INDEX_CONSTRAINT_GE );
    assert( WO_MATCH==SQLITE4_INDEX_CONSTRAINT_MATCH );
    assert( pTerm->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
    j++;
  }
  for(i=0; i<nOrderBy; i++){
    Expr *pExpr = pOrderBy->a[i].pExpr;
    pIdxOrderBy[i].iColumn = pExpr->iColumn;
    pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
  }
................................................................................

  return pIdxInfo;
}

/*
** The table object reference passed as the second argument to this function
** must represent a virtual table. This function invokes the xBestIndex()
** method of the virtual table with the sqlite4_index_info pointer passed
** as the argument.
**
** If an error occurs, pParse is populated with an error message and a
** non-zero value is returned. Otherwise, 0 is returned and the output
** part of the sqlite4_index_info structure is left populated.
**
** Whether or not an error is returned, it is the responsibility of the
** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
................................................................................
** that this is required.
*/
static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite4_index_info *p){
  sqlite4_vtab *pVtab = sqlite4GetVTable(pParse->db, pTab)->pVtab;
  int i;
  int rc;

  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
  TRACE_IDX_INPUTS(p);
  rc = pVtab->pModule->xBestIndex(pVtab, p);
  TRACE_IDX_OUTPUTS(p);

  if( rc!=SQLITE4_OK ){
    if( rc==SQLITE4_NOMEM ){
      pParse->db->mallocFailed = 1;
................................................................................
      sqlite4ErrorMsg(pParse, 
          "table %s: xBestIndex returned an invalid plan", pTab->zName);
    }
  }

  return pParse->nErr;
}



/*
** Compute the best index for a virtual table.
**
** The best index is computed by the xBestIndex method of the virtual
** table module.  This routine is really just a wrapper that sets up
** the sqlite4_index_info structure that is used to communicate with
** xBestIndex.
**
** In a join, this routine might be called multiple times for the
** same virtual table.  The sqlite4_index_info structure is created
** and initialized on the first invocation and reused on all subsequent
** invocations.  The sqlite4_index_info structure is also used when
** code is generated to access the virtual table.  The whereInfoDelete() 
** routine takes care of freeing the sqlite4_index_info structure after
** everybody has finished with it.
*/
static void bestVirtualIndex(
  Parse *pParse,                  /* The parsing context */
  WhereClause *pWC,               /* The WHERE clause */
  SrcListItem *pSrc,      /* The FROM clause term to search */
  Bitmask notReady,               /* Mask of cursors not available for index */
  Bitmask notValid,               /* Cursors not valid for any purpose */
  ExprList *pOrderBy,             /* The order by clause */
  WhereCost *pCost,               /* Lowest cost query plan */
  sqlite4_index_info **ppIdxInfo  /* Index information passed to xBestIndex */
){
  Table *pTab = pSrc->pTab;
  sqlite4_index_info *pIdxInfo;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int i, j;
  int nOrderBy;
  double rCost;

  /* Make sure wsFlags is initialized to some sane value. Otherwise, if the 
  ** malloc in allocateIndexInfo() fails and this function returns leaving
  ** wsFlags in an uninitialized state, the caller may behave unpredictably.
  */
  memset(pCost, 0, sizeof(*pCost));
  pCost->plan.wsFlags = WHERE_VIRTUALTABLE;

  /* If the sqlite4_index_info structure has not been previously
  ** allocated and initialized, then allocate and initialize it now.
  */
  pIdxInfo = *ppIdxInfo;
  if( pIdxInfo==0 ){
    *ppIdxInfo = pIdxInfo = allocateIndexInfo(pParse, pWC, pSrc, pOrderBy);
  }
  if( pIdxInfo==0 ){
    return;
  }

  /* At this point, the sqlite4_index_info structure that pIdxInfo points
  ** to will have been initialized, either during the current invocation or
  ** during some prior invocation.  Now we just have to customize the
  ** details of pIdxInfo for the current invocation and pass it to
  ** xBestIndex.
  */

  /* The module name must be defined. Also, by this point there must
  ** be a pointer to an sqlite4_vtab structure. Otherwise
  ** sqlite4ViewGetColumnNames() would have picked up the error. 
  */
  assert( pTab->azModuleArg && pTab->azModuleArg[0] );
  assert( sqlite4GetVTable(pParse->db, pTab) );

  /* Set the aConstraint[].usable fields and initialize all 
  ** output variables to zero.
  **
  ** aConstraint[].usable is true for constraints where the right-hand
  ** side contains only references to tables to the left of the current
  ** table.  In other words, if the constraint is of the form:
  **
  **           column = expr
  **
  ** and we are evaluating a join, then the constraint on column is 
  ** only valid if all tables referenced in expr occur to the left
  ** of the table containing column.
  **
  ** The aConstraints[] array contains entries for all constraints
  ** on the current table.  That way we only have to compute it once
  ** even though we might try to pick the best index multiple times.
  ** For each attempt at picking an index, the order of tables in the
  ** join might be different so we have to recompute the usable flag
  ** each time.
  */
  pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
  pUsage = pIdxInfo->aConstraintUsage;
  for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
    j = pIdxCons->iTermOffset;
    pTerm = &pWC->a[j];
    pIdxCons->usable = (pTerm->prereqRight&notReady) ? 0 : 1;
  }
  memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
  if( pIdxInfo->needToFreeIdxStr ){
    sqlite4_free(pIdxInfo->idxStr);
  }
  pIdxInfo->idxStr = 0;
  pIdxInfo->idxNum = 0;
  pIdxInfo->needToFreeIdxStr = 0;
  pIdxInfo->orderByConsumed = 0;
  /* ((double)2) In case of SQLITE4_OMIT_FLOATING_POINT... */
  pIdxInfo->estimatedCost = SQLITE4_BIG_DBL / ((double)2);
  nOrderBy = pIdxInfo->nOrderBy;
  if( !pOrderBy ){
    pIdxInfo->nOrderBy = 0;
  }

  if( vtabBestIndex(pParse, pTab, pIdxInfo) ){
    return;
  }

  pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++){
    if( pUsage[i].argvIndex>0 ){
      pCost->used |= pWC->a[pIdxCons[i].iTermOffset].prereqRight;
    }
  }

  /* If there is an ORDER BY clause, and the selected virtual table index
  ** does not satisfy it, increase the cost of the scan accordingly. This
  ** matches the processing for non-virtual tables in bestKVIndex().
  */
  rCost = pIdxInfo->estimatedCost;
  if( pOrderBy && pIdxInfo->orderByConsumed==0 ){
    rCost += estLog(rCost)*rCost;
  }

  /* The cost is not allowed to be larger than SQLITE4_BIG_DBL (the
  ** inital value of lowestCost in this loop. If it is, then the
  ** (cost<lowestCost) test below will never be true.
  ** 
  ** Use "(double)2" instead of "2.0" in case OMIT_FLOATING_POINT 
  ** is defined.
  */
  if( (SQLITE4_BIG_DBL/((double)2))<rCost ){
    pCost->rCost = (SQLITE4_BIG_DBL/((double)2));
  }else{
    pCost->rCost = rCost;
  }
  pCost->plan.u.pVtabIdx = pIdxInfo;
  if( pIdxInfo->orderByConsumed ){
    pCost->plan.wsFlags |= WHERE_ORDERBY;
  }
  pCost->plan.nEq = 0;
  pIdxInfo->nOrderBy = nOrderBy;

  /* Try to find a more efficient access pattern by using multiple indexes
  ** to optimize an OR expression within the WHERE clause. 
  */
  bestOrClauseIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost);
}
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the location of a particular key among all keys in an
** index.  Store the results in aStat as follows:
**
**    aStat[0]      Est. number of rows less than pVal
**    aStat[1]      Est. number of rows equal to pVal
**
** Return SQLITE4_OK on success.
*/
static int whereKeyStats(
  Parse *pParse,              /* Database connection */
  Index *pIdx,                /* Index to consider domain of */
  sqlite4_buffer *pBuf,       /* Buffer containing encoded value to consider */

  int roundUp,                /* Round up if true.  Round down if false */
  tRowcnt *aStat              /* OUT: stats written here */
){
  tRowcnt n;
  IndexSample *aSample;
  int i;
  int isEq = 0;



  assert( roundUp==0 || roundUp==1 );
  assert( pIdx->nSample>0 );
  assert( pBuf->n>0 );

  n = pIdx->aiRowEst[0];
  aSample = pIdx->aSample;













  /* Set variable i to the index of the first sample equal to or larger 
  ** than the value in pBuf. Set isEq to true if the value is equal, or
  ** false otherwise.  */










  for(i=0; i<pIdx->nSample; i++){
    int res;
    int n = pBuf->n;



    if( n>aSample[i].nVal ) n = aSample[i].nVal;



    res = memcmp(pBuf->p, aSample[i].aVal, n);
    if( res==0 ) res = pBuf->n - aSample[i].nVal;
    if( res<=0 ){
      isEq = (res==0);
      break;





























































    }
  }

  /* At this point, aSample[i] is the first sample that is greater than
  ** or equal to pVal.  Or if i==pIdx->nSample, then all samples are less
  ** than pVal.  If aSample[i]==pVal, then isEq==1.
  */
................................................................................
    aStat[0] = iLower + iGap;
  }
  return SQLITE4_OK;
}
#endif /* SQLITE4_ENABLE_STAT3 */

/*
** If expression pExpr represents a literal value, extract it and apply
** the affinity aff to it. Then encode the value using the database index
** key encoding and write the result into buffer pBuf.


**
** If the current parse is a recompile (sqlite4Reprepare()) and pExpr
** is an SQL variable that currently has a non-NULL value bound to it,
** do the same with the bound value.

**
** If neither of the above apply, leave the buffer empty.
**
** If an error occurs, return an error code. Otherwise, SQLITE4_OK.
*/
#ifdef SQLITE4_ENABLE_STAT3
static int valueFromExpr(
  Parse *pParse,                  /* Parse context */
  KeyInfo *pKeyinfo,              /* Collation sequence and sort order */
  Expr *pExpr,                    /* Expression to extract value from */
  u8 aff,                         /* Affinity to apply to value */
  sqlite4_buffer *pBuf            /* Buffer to populate */
){
  int rc = SQLITE4_OK;
  sqlite4 *db = pParse->db;
  sqlite4_value *pVal = 0;

  assert( pBuf->n==0 );

  if( pExpr->op==TK_VARIABLE
   || (pExpr->op==TK_REGISTER && pExpr->op2==TK_VARIABLE)
  ){
    int iVar = pExpr->iColumn;
    sqlite4VdbeSetVarmask(pParse->pVdbe, iVar);
    pVal = sqlite4VdbeGetValue(pParse->pReprepare, iVar, aff);
  }else{
    rc = sqlite4ValueFromExpr(db, pExpr, SQLITE4_UTF8, aff, &pVal);
  }

  if( pVal && rc==SQLITE4_OK ){
    u8 *aOut;
    int nOut;
    rc = sqlite4VdbeEncodeKey(db, pVal, 1, 2, -1, pKeyinfo, &aOut, &nOut, 0);
    if( rc==SQLITE4_OK ){
      rc = sqlite4_buffer_set(pBuf, aOut, nOut);
    }
    sqlite4DbFree(db, aOut);

  }

  sqlite4ValueFree(pVal);
  return SQLITE4_OK;
}
#endif

static int whereSampleKeyinfo(Parse *pParse, Index *p, KeyInfo *pKeyInfo){
  CollSeq *pColl;
  memset(pKeyInfo, 0, sizeof(KeyInfo));
  pKeyInfo->db = pParse->db;
  pKeyInfo->enc = SQLITE4_UTF8;
  pKeyInfo->nField = p->nColumn;
  pKeyInfo->nPK = 1;
  pKeyInfo->nData = 0;
  pKeyInfo->aSortOrder = p->aSortOrder;
  pKeyInfo->aColl[0] = pColl = sqlite4LocateCollSeq(pParse, p->azColl[0]);
  pKeyInfo->aColl[0] = pColl;
  return pColl ? SQLITE4_OK : SQLITE4_ERROR;
}

/*
** This function is used to estimate the number of rows that will be visited
** by scanning an index for a range of values. The range may have an upper
** bound, a lower bound, or both. The WHERE clause terms that set the upper
** and lower bounds are represented by pLower and pUpper respectively. For
** example, assuming that index p is on t1(a):
**
................................................................................
*/
static int whereRangeScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index containing the range-compared column; "x" */
  int nEq,             /* index into p->aCol[] of the range-compared column */
  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
  double *pRangeDiv   /* OUT: Reduce search space by this divisor */
){
  int rc = SQLITE4_OK;

#ifdef SQLITE4_ENABLE_STAT3

  if( nEq==0 && p->nSample ){
    sqlite4 *db = pParse->db;
    KeyInfo keyinfo;
    sqlite4_buffer buf;              /* Buffer used for index sample */
    tRowcnt iLower = 0;
    tRowcnt iUpper = p->aiRowEst[0];
    tRowcnt a[2];
    u8 aff = p->pTable->aCol[p->aiColumn[0]].affinity;

    sqlite4_buffer_init(&buf, db->pEnv->pMM);
    rc = whereSampleKeyinfo(pParse, p, &keyinfo);

    if( rc==SQLITE4_OK && pLower ){
      Expr *pExpr = pLower->pExpr->pRight;
      rc = valueFromExpr(pParse, &keyinfo, pExpr, aff, &buf);
      assert( pLower->eOperator==WO_GT || pLower->eOperator==WO_GE );

      if( rc==SQLITE4_OK && buf.n
       && whereKeyStats(pParse, p, &buf, 0, a)==SQLITE4_OK
      ){
        iLower = a[0];
        if( pLower->eOperator==WO_GT ) iLower += a[1];

      }
      sqlite4_buffer_set(&buf, 0, 0);

    }
    if( rc==SQLITE4_OK && pUpper ){
      Expr *pExpr = pUpper->pExpr->pRight;
      rc = valueFromExpr(pParse, &keyinfo, pExpr, aff, &buf);
      assert( pUpper->eOperator==WO_LT || pUpper->eOperator==WO_LE );
      if( rc==SQLITE4_OK && buf.n
       && whereKeyStats(pParse, p, &buf, 1, a)==SQLITE4_OK
      ){
        iUpper = a[0];
        if( pUpper->eOperator==WO_LE ) iUpper += a[1];
      }

    }
    sqlite4_buffer_clear(&buf);
    if( rc==SQLITE4_OK ){

      if( iUpper<=iLower ){
        *pRangeDiv = (double)p->aiRowEst[0];
      }else{
        *pRangeDiv = (double)p->aiRowEst[0]/(double)(iUpper - iLower);
      }

      WHERETRACE(("range scan regions: %u..%u  div=%g\n",
                  (u32)iLower, (u32)iUpper, *pRangeDiv));
      return SQLITE4_OK;
    }
  }
#else
  UNUSED_PARAMETER(pParse);
  UNUSED_PARAMETER(p);
  UNUSED_PARAMETER(nEq);
#endif
  assert( pLower || pUpper );
  *pRangeDiv = (double)1;


  if( pLower && (pLower->wtFlags & TERM_VNULL)==0 ) *pRangeDiv *= (double)4;


  if( pUpper ) *pRangeDiv *= (double)4;


  return rc;
}

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
** an equality constraint x=VALUE and where that VALUE occurs in
................................................................................
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereEqualScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
  double *pnRow        /* Write the revised row estimate here */
){
  sqlite4_buffer buf;
  u8 aff;                   /* Column affinity */
  int rc;                   /* Subfunction return code */
  tRowcnt a[2];             /* Statistics */

  assert( p->aSample!=0 );
  assert( p->nSample>0 );

  sqlite4_buffer_init(&buf, pParse->db->pEnv->pMM);
  aff = p->pTable->aCol[p->aiColumn[0]].affinity;
  if( pExpr ){
    KeyInfo keyinfo;
    rc = whereSampleKeyinfo(pParse, p, &keyinfo);
    if( rc==SQLITE4_OK ){
      rc = valueFromExpr(pParse, &keyinfo, pExpr, aff, &buf);
      if( buf.n==0 ) return SQLITE4_NOTFOUND;
    }

  }else{
    /* Populate the buffer with a NULL. */
    u8 aNull[2] = {0x05, 0xfa};        /* ASC, DESC */
    rc = sqlite4_buffer_set(&buf, &aNull[p->aSortOrder[0]], 1);

  }
  if( rc ) goto whereEqualScanEst_cancel;


  rc = whereKeyStats(pParse, p, &buf, 0, a);
  if( rc==SQLITE4_OK ){
    WHERETRACE(("equality scan regions: %d\n", (int)a[1]));
    *pnRow = a[1];
  }
whereEqualScanEst_cancel:
  sqlite4_buffer_clear(&buf);
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
................................................................................
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereInScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
  double *pnRow        /* Write the revised row estimate here */
){
  int rc = SQLITE4_OK;         /* Subfunction return code */
  double nEst;                /* Number of rows for a single term */
  double nRowEst = (double)0; /* New estimate of the number of rows */
  int i;                      /* Loop counter */

  assert( p->aSample!=0 );
  for(i=0; rc==SQLITE4_OK && i<pList->nExpr; i++){
    nEst = p->aiRowEst[0];
    rc = whereEqualScanEst(pParse, p, pList->a[i].pExpr, &nEst);
    nRowEst += nEst;
  }
  if( rc==SQLITE4_OK ){
    if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0];
    *pnRow = nRowEst;
    WHERETRACE(("IN row estimate: est=%g\n", nRowEst));
  }
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */

/*
** Try to find a MATCH expression that constrains the pTabItem table in the
** WHERE clause. If one exists, set *piTerm to the index in the pWC->a[] array
** and return non-zero. If no such expression exists, return 0.
*/
static int findMatchExpr(
  Parse *pParse, 
  WhereClause *pWC, 
  SrcListItem *pTabItem, 
  int *piTerm
){
  int i;
  int iCsr = pTabItem->iCursor;

  for(i=0; i<pWC->nTerm; i++){
    Expr *pMatch = pWC->a[i].pExpr;
    if( pMatch->iTable==iCsr && pMatch->op==TK_MATCH ) break;
  }
  if( i==pWC->nTerm ) return 0;

  *piTerm = i;
  return 1;
}

static int bestMatchIdx(
  Parse *pParse, 
  WhereClause *pWC, 
  SrcListItem *pTabItem, 
  Bitmask notReady, 
  WhereCost *pCost
){
  int iTerm;

  if( 0==findMatchExpr(pParse, pWC, pTabItem, &iTerm) ) return 0;

  /* Check that the MATCH expression is not composed using values from any
  ** tables that are not ready. If it does, return 0. */
  if( notReady & pWC->a[iTerm].prereqAll ) return 0;

  pCost->used = pWC->a[iTerm].prereqAll;
  pCost->rCost = 1.0;
  pCost->plan.wsFlags = WHERE_INDEXED;
  pCost->plan.nEq = 0;
  pCost->plan.nRow = 10;
  pCost->plan.u.pIdx = pWC->a[iTerm].pExpr->pIdx;
  return 1;
}

/*
** Find the best query plan for accessing a particular table.  Write the
** best query plan and its cost into the WhereCost object supplied as the
** last parameter.
**
** The lowest cost plan wins.  The cost is an estimate of the amount of
** CPU and disk I/O needed to process the requested result.
** Factors that influence cost include:
**
**    *  The estimated number of rows that will be retrieved.  (The
**       fewer the better.)
**
**    *  Whether or not sorting must occur.
**
**    *  Whether or not there must be separate lookups in the
**       index and in the main table.
**
** If there was an INDEXED BY clause (pSrc->pIndex) attached to the table in
** the SQL statement, then this function only considers plans using the 
** named index. If no such plan is found, then the returned cost is
** SQLITE4_BIG_DBL. If a plan is found that uses the named index, 
** then the cost is calculated in the usual way.
**
** If a NOT INDEXED clause (pSrc->notIndexed!=0) was attached to the table 
** in the SELECT statement, then no indexes are considered. However, the 
** selected plan may still take advantage of the built-in rowid primary key
** index.
*/
static void bestKVIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors not available for indexing */
  Bitmask notValid,           /* Cursors not available for any purpose */
  ExprList *pOrderBy,         /* The ORDER BY clause */
  ExprList *pDistinct,        /* The select-list if query is DISTINCT */
  WhereCost *pCost            /* Lowest cost query plan */
){
  int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
  Index *pProbe;              /* An index we are evaluating */
  Index *pFirst;              /* First index to evaluate */
  Index *pPk;                 /* Primary Key index */
  int eqTermMask;             /* Current mask of valid equality operators */
  int idxEqTermMask;          /* Index mask of valid equality operators */

  /* Initialize the cost to a worst-case value */
  memset(pCost, 0, sizeof(*pCost));
  pCost->rCost = SQLITE4_BIG_DBL;
  pPk = sqlite4FindPrimaryKey(pSrc->pTab, 0);

  /* If the pSrc table is the right table of a LEFT JOIN then we may not
  ** use an index to satisfy IS NULL constraints on that table.  This is
  ** because columns might end up being NULL if the table does not match -
  ** a circumstance which the index cannot help us discover.  Ticket #2177.
  */
  if( pSrc->jointype & JT_LEFT ){
    idxEqTermMask = WO_EQ|WO_IN;
  }else{
    idxEqTermMask = WO_EQ|WO_IN|WO_ISNULL;
  }

  /* Normally, this function considers all indexes attached to the table
  ** being queried. Except, if an INDEXED BY clause is specified then only
  ** the named index is considered. And if a NOT INDEXED clause was present
  ** only the PRIMARY KEY index may be considered.  
  */
  if( pSrc->notIndexed ){
    pFirst = pPk;
  }else if( pSrc->pIndex ){
    pFirst = pSrc->pIndex;
  }else{
    pFirst = pSrc->pTab->pIndex;
  }
  eqTermMask = idxEqTermMask;

  /* Loop over all indices looking for the best one to use */
  for(pProbe=pFirst; pProbe; pProbe=pProbe->pNext){
    const tRowcnt * const aiRowEst = pProbe->aiRowEst;
    double cost;                /* Cost of using pProbe */
    double nRow;                /* Estimated number of rows in result set */
    double log10N = (double)1;  /* base-10 logarithm of nRow (inexact) */
    int rev;                    /* True to scan in reverse order */
    int wsFlags = 0;
    Bitmask used = 0;

    /* The following variables are populated based on the properties of
    ** index being evaluated. They are then used to determine the expected
    ** cost and number of rows returned.
    **
    **  nEq: 
    **    Number of equality terms that can be implemented using the index.
    **    In other words, the number of initial fields in the index that
    **    are used in == or IN or NOT NULL constraints of the WHERE clause.
    **
    **  nInMul:  
    **    The "in-multiplier". This is an estimate of how many seek operations 
    **    SQLite must perform on the index in question. For example, if the 
    **    WHERE clause is:
    **
    **      WHERE a IN (1, 2, 3) AND b IN (4, 5, 6)
    **
    **    SQLite must perform 9 lookups on an index on (a, b), so nInMul is 
    **    set to 9. Given the same schema and either of the following WHERE 
    **    clauses:
    **
    **      WHERE a =  1
    **      WHERE a >= 2
    **
    **    nInMul is set to 1.
    **
    **    If there exists a WHERE term of the form "x IN (SELECT ...)", then 
    **    the sub-select is assumed to return 25 rows for the purposes of 
    **    determining nInMul.
    **
    **  bInEst:  
    **    Set to true if there was at least one "x IN (SELECT ...)" term used 
    **    in determining the value of nInMul.  Note that the RHS of the
    **    IN operator must be a SELECT, not a value list, for this variable
    **    to be true.
    **
    **  rangeDiv:
    **    An estimate of a divisor by which to reduce the search space due
    **    to inequality constraints.  In the absence of sqlite_stat3 ANALYZE
    **    data, a single inequality reduces the search space to 1/4rd its
    **    original size (rangeDiv==4).  Two inequalities reduce the search
    **    space to 1/16th of its original size (rangeDiv==16).
    **
    **  bSort:   
    **    Boolean. True if there is an ORDER BY clause that will require an 
    **    external sort (i.e. scanning the index being evaluated will not 
    **    correctly order records).
    **
    **  bLookup: 
    **    Boolean. True if a table lookup is required for each index entry
    **    visited.  In other words, true if this is not a covering index.
    **    This is always false for the rowid primary key index of a table.
    **    For other indexes, it is true unless all the columns of the table
    **    used by the SELECT statement are present in the index (such an
    **    index is sometimes described as a covering index).
    **    For example, given the index on (a, b), the second of the following 
    **    two queries requires table b-tree lookups in order to find the value
    **    of column c, but the first does not because columns a and b are
    **    both available in the index.
    **
    **             SELECT a, b    FROM tbl WHERE a = 1;
    **             SELECT a, b, c FROM tbl WHERE a = 1;
    */
    int nEq;                      /* Number of == or IN terms matching index */
    int bInEst = 0;               /* True if "x IN (SELECT...)" seen */
    int nInMul = 1;               /* Number of distinct equalities to lookup */
    double rangeDiv = (double)1;  /* Estimated reduction in search space */
    int nBound = 0;               /* Number of range constraints seen */
    int bSort = !!pOrderBy;       /* True if external sort required */
    int bDist = !!pDistinct;      /* True if index cannot help with DISTINCT */
    int bLookup = 0;              /* True if not the PK index */
    WhereTerm *pTerm;             /* A single term of the WHERE clause */
#ifdef SQLITE4_ENABLE_STAT3
    WhereTerm *pFirstTerm = 0;    /* First term matching the index */
#endif
    int nCol = pProbe->nColumn;   /* Total columns in index record */

    if( pProbe->eIndexType==SQLITE4_INDEX_FTS5 ) continue;

    /* Unless pProbe is the primary key index, then the encoded PK column 
    ** values are at the end of each record. Set variable nCol to the total
    ** number of columns encoded into each index record, including the PK  
    ** columns.  */
    if( pProbe!=pPk ) nCol += pPk->nColumn;

    /* Determine the values of nEq and nInMul */
    for(nEq=0; nEq<nCol; nEq++){
      int iCol;                   /* Table column of nEq'th index field */
      iCol = idxColumnNumber(pProbe, pPk, nEq);
      pTerm = findTerm(pWC, iCur, iCol, notReady, eqTermMask, pProbe);
      if( pTerm==0 ) break;
      wsFlags |= WHERE_COLUMN_EQ;
      testcase( pTerm->pWC!=pWC );
      if( pTerm->eOperator & WO_IN ){
        Expr *pExpr = pTerm->pExpr;
        wsFlags |= WHERE_COLUMN_IN;
        if( ExprHasProperty(pExpr, EP_xIsSelect) ){
          /* "x IN (SELECT ...)":  Assume the SELECT returns 25 rows */
          nInMul *= 25;
          bInEst = 1;
        }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
          /* "x IN (value, value, ...)" */
          nInMul *= pExpr->x.pList->nExpr;
        }
      }else if( pTerm->eOperator & WO_ISNULL ){
        wsFlags |= WHERE_COLUMN_NULL;
      }
#ifdef SQLITE4_ENABLE_STAT3
      if( nEq==0 && pProbe->aSample ) pFirstTerm = pTerm;
#endif
      used |= pTerm->prereqRight;
    }
 
    /* If the index being considered is UNIQUE, and there is an equality 
    ** constraint for all columns in the index, then this search will find
    ** at most a single row. In this case set the WHERE_UNIQUE flag to 
    ** indicate this to the caller.
    **
    ** Otherwise, if the search may find more than one row, test to see if
    ** there is a range constraint on indexed column (nEq+1) that can be 
    ** optimized using the index. 
    */
    if( nEq>=pProbe->nColumn && pProbe->onError!=OE_None ){
      testcase( wsFlags & WHERE_COLUMN_IN );
      testcase( wsFlags & WHERE_COLUMN_NULL );
      if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0 ){
        wsFlags |= WHERE_UNIQUE;
      }
    }else if( (pProbe->fIndex & IDX_Unordered)==0 ){
      int j = idxColumnNumber(pProbe, pPk, nEq);
      if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe) ){
        WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe);
        WhereTerm *pBtm = findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe);
        whereRangeScanEst(pParse, pProbe, nEq, pBtm, pTop, &rangeDiv);
        if( pTop ){
          nBound = 1;
          wsFlags |= WHERE_TOP_LIMIT;
          used |= pTop->prereqRight;
          testcase( pTop->pWC!=pWC );
        }
        if( pBtm ){
          nBound++;
          wsFlags |= WHERE_BTM_LIMIT;
          used |= pBtm->prereqRight;
          testcase( pBtm->pWC!=pWC );
        }
        wsFlags |= WHERE_COLUMN_RANGE;
      }
    }

    /* If there is an ORDER BY clause and the index being considered will
    ** naturally scan rows in the required order, set the appropriate flags
    ** in wsFlags. Otherwise, if there is an ORDER BY clause but the index
    ** will scan rows in a different order, set the bSort variable.  */
    if( isSortingIndex(
          pParse, pWC->pMaskSet, pProbe, iCur, pOrderBy, nEq, wsFlags, &rev)
    ){
      bSort = 0;
      wsFlags |= WHERE_COLUMN_RANGE|WHERE_ORDERBY;
      wsFlags |= (rev ? WHERE_REVERSE : 0);
    }

    /* If there is a DISTINCT qualifier and this index will scan rows in
    ** order of the DISTINCT expressions, clear bDist and set the appropriate
    ** flags in wsFlags. */
    if( isDistinctIndex(pParse, pWC, pProbe, iCur, pDistinct, nEq) ){
      bDist = 0;
      wsFlags |= WHERE_COLUMN_RANGE|WHERE_DISTINCT;
    }

    /* If currently calculating the cost of using an index (not the PK
    ** index), determine if all required column data may be obtained without 
    ** using the main table (i.e. if the index is a covering
    ** index for this query). If it is, set the WHERE_IDX_ONLY flag in
    ** wsFlags. Otherwise, set the bLookup variable to true.  
    **
    ** TODO: Not clear if this optimization can be applied in SQLite 4. Fix
    ** this block once that is figured out.
    */
#if 0
    if( wsFlags ){
      Bitmask m = pSrc->colUsed;
      int j;
      for(j=0; j<pProbe->nColumn; j++){
        int x = pProbe->aiColumn[j];
        if( x<BMS-1 ){
          m &= ~(((Bitmask)1)<<x);
        }
      }
      if( m==0 ){
        wsFlags |= WHERE_IDX_ONLY;
      }else{
        bLookup = 1;
      }
    }
#endif
    bLookup = (pProbe->eIndexType!=SQLITE4_INDEX_PRIMARYKEY);

    /*
    ** Estimate the number of rows of output.  For an "x IN (SELECT...)"
    ** constraint, do not let the estimate exceed half the rows in the table.
    */
    nRow = (double)(aiRowEst[nEq] * nInMul);
    if( bInEst && nRow*2>aiRowEst[0] ){
      nRow = aiRowEst[0]/2;
      nInMul = (int)(nRow / aiRowEst[nEq]);
    }

#ifdef SQLITE4_ENABLE_STAT3
    /* If the constraint is of the form x=VALUE or x IN (E1,E2,...)
    ** and we do not think that values of x are unique and if histogram
    ** data is available for column x, then it might be possible
    ** to get a better estimate on the number of rows based on
    ** VALUE and how common that value is according to the histogram.
    */
    if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 && aiRowEst[1]>1 ){
      assert( (pFirstTerm->eOperator & (WO_EQ|WO_ISNULL|WO_IN))!=0 );
      if( pFirstTerm->eOperator & (WO_EQ|WO_ISNULL) ){
        testcase( pFirstTerm->eOperator==WO_EQ );
        testcase( pFirstTerm->eOperator==WO_ISNULL );
        whereEqualScanEst(pParse, pProbe, pFirstTerm->pExpr->pRight, &nRow);
      }else if( bInEst==0 ){
        assert( pFirstTerm->eOperator==WO_IN );
        whereInScanEst(pParse, pProbe, pFirstTerm->pExpr->x.pList, &nRow);
      }
    }
#endif /* SQLITE4_ENABLE_STAT3 */

    /* Adjust the number of output rows and downward to reflect rows
    ** that are excluded by range constraints.
    */
    nRow = nRow/rangeDiv;
    if( nRow<1 ) nRow = 1;

    /* Experiments run on real SQLite databases show that the time needed
    ** to do a binary search to locate a row in a table or index is roughly
    ** log10(N) times the time to move from one row to the next row within
    ** a table or index.  The actual times can vary, with the size of
    ** records being an important factor.  Both moves and searches are
    ** slower with larger records, presumably because fewer records fit
    ** on one page and hence more pages have to be fetched.
    **
    ** The ANALYZE command and the sqlite_stat1 and sqlite_stat3 tables do
    ** not give us data on the relative sizes of table and index records.
    ** So this computation assumes table records are about twice as big
    ** as index records
    */
    if( (wsFlags & WHERE_NOT_FULLSCAN)==0 ){
      /* The cost of a full table scan is a number of move operations equal
      ** to the number of rows in the table.
      **
      ** We add an additional 4x penalty to full table scans.  This causes
      ** the cost function to err on the side of choosing an index over
      ** choosing a full scan.  This 4x full-scan penalty is an arguable
      ** decision and one which we expect to revisit in the future.  But
      ** it seems to be working well enough at the moment.
      */
      cost = aiRowEst[0]*4;
    }else{
      log10N = estLog(aiRowEst[0]);
      cost = nRow;
      if( bLookup ){
        /* For an index lookup followed by a table lookup:
        **    nInMul index searches to find the start of each index range
        **  + nRow steps through the index
        **  + nRow table searches to lookup the table entry using the PK
        */
        cost += (nInMul + nRow)*log10N;
      }else{
        /* For a covering index:
        **     nInMul index searches to find the initial entry 
        **   + nRow steps through the index
        */
        cost += nInMul*log10N;
      }
    }

    /* Add in the estimated cost of sorting the result.  Actual experimental
    ** measurements of sorting performance in SQLite show that sorting time
    ** adds C*N*log10(N) to the cost, where N is the number of rows to be 
    ** sorted and C is a factor between 1.95 and 4.3.  We will split the
    ** difference and select C of 3.0.
    */
    if( bSort ){
      cost += nRow*estLog(nRow)*3;
    }
    if( bDist ){
      cost += nRow*estLog(nRow)*3;
    }

    /**** Cost of using this index has now been computed ****/

    /* If there are additional constraints on this table that cannot
    ** be used with the current index, but which might lower the number
    ** of output rows, adjust the nRow value accordingly.  This only 
    ** matters if the current index is the least costly, so do not bother
    ** with this step if we already know this index will not be chosen.
    ** Also, never reduce the output row count below 2 using this step.
    **
    ** It is critical that the notValid mask be used here instead of
    ** the notReady mask.  When computing an "optimal" index, the notReady
    ** mask will only have one bit set - the bit for the current table.
    ** The notValid mask, on the other hand, always has all bits set for
    ** tables that are not in outer loops.  If notReady is used here instead
    ** of notValid, then a optimal index that depends on inner joins loops
    ** might be selected even when there exists an optimal index that has
    ** no such dependency.
    */
    if( nRow>2 && cost<=pCost->rCost ){
      int k;                       /* Loop counter */
      int nSkipEq = nEq;           /* Number of == constraints to skip */
      int nSkipRange = nBound;     /* Number of < constraints to skip */
      Bitmask thisTab;             /* Bitmap for pSrc */

      thisTab = getMask(pWC->pMaskSet, iCur);
      for(pTerm=pWC->a, k=pWC->nTerm; nRow>2 && k; k--, pTerm++){
        if( pTerm->wtFlags & TERM_VIRTUAL ) continue;
        if( (pTerm->prereqAll & notValid)!=thisTab ) continue;
        if( pTerm->eOperator & (WO_EQ|WO_IN|WO_ISNULL) ){
          if( nSkipEq ){
            /* Ignore the first nEq equality matches since the index
            ** has already accounted for these */
            nSkipEq--;
          }else{
            /* Assume each additional equality match reduces the result
            ** set size by a factor of 10 */
            nRow /= 10;
          }
        }else if( pTerm->eOperator & (WO_LT|WO_LE|WO_GT|WO_GE) ){
          if( nSkipRange ){
            /* Ignore the first nSkipRange range constraints since the index
            ** has already accounted for these */
            nSkipRange--;
          }else{
            /* Assume each additional range constraint reduces the result
            ** set size by a factor of 3.  Indexed range constraints reduce
            ** the search space by a larger factor: 4.  We make indexed range
            ** more selective intentionally because of the subjective 
            ** observation that indexed range constraints really are more
            ** selective in practice, on average. */
            nRow /= 3;
          }
        }else if( pTerm->eOperator!=WO_NOOP ){
          /* Any other expression lowers the output row count by half */
          nRow /= 2;
        }
      }
      if( nRow<2 ) nRow = 2;
    }


    WHERETRACE((
      "%s(%s): nEq=%d nInMul=%d rangeDiv=%d bSort=%d bLookup=%d wsFlags=0x%x\n"
      "         notReady=0x%llx log10N=%.1f nRow=%.1f cost=%.1f used=0x%llx\n",
      pSrc->pTab->zName, pProbe->zName,
      nEq, nInMul, (int)rangeDiv, bSort, bLookup, wsFlags,
      notReady, log10N, nRow, cost, used
    ));

    /* If this index is the best we have seen so far, then record this
    ** index and its cost in the pCost structure.
    */
    if( (pProbe==pFirst || wsFlags || pProbe==pPk)
     && (cost<pCost->rCost || (cost<=pCost->rCost && nRow<pCost->plan.nRow))
    ){
      pCost->rCost = cost;
      pCost->used = used;
      pCost->plan.nRow = nRow;
      pCost->plan.wsFlags = wsFlags;
      pCost->plan.nEq = nEq;
      pCost->plan.u.pIdx = pProbe;
    }

    /* If there was an INDEXED BY or NOT INDEXED clause, only one index is
    ** considered. */
    if( pSrc->pIndex || pSrc->notIndexed ) break;
  }

  /* If there is no ORDER BY clause and the SQLITE4_ReverseOrder flag
  ** is set, then reverse the order that the index will be scanned
  ** in. This is used for application testing, to help find cases
  ** where application behaviour depends on the (undefined) order that
  ** SQLite outputs rows in in the absence of an ORDER BY clause.  */
  if( !pOrderBy && pParse->db->flags & SQLITE4_ReverseOrder ){
    pCost->plan.wsFlags |= WHERE_REVERSE;
  }

  assert( pOrderBy || (pCost->plan.wsFlags&WHERE_ORDERBY)==0 );
  assert( pSrc->pIndex==0 
       || pCost->plan.u.pIdx==0 
       || pCost->plan.u.pIdx==pSrc->pIndex 
  );

  WHERETRACE(("best index is: %s\n", 
    ((pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ? "none" : 
         pCost->plan.u.pIdx ? pCost->plan.u.pIdx->zName : "ipk")
  ));
  
  bestOrClauseIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost);
  bestAutomaticIndex(pParse, pWC, pSrc, notReady, pCost);
  pCost->plan.wsFlags |= eqTermMask;
}

/*
** Find the query plan for accessing table pSrc->pTab. Write the
** best query plan and its cost into the WhereCost object supplied 
** as the last parameter. This function may calculate the cost of
** both real and virtual table scans.
*/
static void bestIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors not available for indexing */
  Bitmask notValid,           /* Cursors not available for any purpose */
  ExprList *pOrderBy,         /* The ORDER BY clause */
  WhereCost *pCost            /* Lowest cost query plan */
){
#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if( IsVirtual(pSrc->pTab) ){
    sqlite4_index_info *p = 0;
    bestVirtualIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost,&p);
    if( p->needToFreeIdxStr ){
      sqlite4_free(p->idxStr);
    }
    sqlite4DbFree(pParse->db, p);
  }else
#endif
  {
    bestKVIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, 0, pCost);
  }
}

/*
** Disable a term in the WHERE clause.  Except, do not disable the term
** if it controls a LEFT OUTER JOIN and it did not originate in the ON
** or USING clause of that join.
**
** Consider the term t2.z='ok' in the following queries:
**
................................................................................
** For a constraint of the form X=expr, the expression is evaluated and its
** result is left on the stack.  For constraints of the form X IN (...)
** this routine sets up a loop that will iterate over all values of X.
*/
static int codeEqualityTerm(
  Parse *pParse,      /* The parsing context */
  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
  WhereLevel *pLevel, /* When level of the FROM clause we are working on */


  int iTarget         /* Attempt to leave results in this register */
){
  Expr *pX = pTerm->pExpr;
  Vdbe *v = pParse->pVdbe;
  int iReg;                  /* Register holding results */

  assert( iTarget>0 );
................................................................................
  if( pX->op==TK_EQ ){
    iReg = sqlite4ExprCodeTarget(pParse, pX->pRight, iTarget);
  }else if( pX->op==TK_ISNULL ){
    iReg = iTarget;
    sqlite4VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE4_OMIT_SUBQUERY
  }else{
    /* Code a loop that iterates through the set of distinct, non-null 
    ** values in the set on the right-hand-side of the IN(...) operator.
    ** There are two ways to do this:
    **
    **   * If the SELECT statement is of the form "SELECT x FROM tbl", 
    **     and column x is subject to a UNIQUE constraint, and the 
    **     default affinity and collation sequence of column "x" match
    **     those required by the comparison, iterate through the PK
    **     index.
    **
    **   * Otherwise, materialize the set into an ephemeral index using
    **     "x" as both the key and value. Then loop through the contents
    **     of the ephemeral index.
    */
    sqlite4 *db = pParse->db;
    int iTab;
    int iCol;                     /* Column to read from cursor iTab */
    struct InLoop *pIn;










    assert( pX->op==TK_IN );
    iReg = iTarget;





    if( sqlite4FindExistingInIndex(pParse, pX, 1) ){
      /* This branch is taken if the rhs of the IN is a select of the
      ** form "SELECT x FROM tble" and column x is subject to a UNIQUE 
      ** constraint that uses the same collation sequence and affinity as
      ** this IN (...) test. In this case just loop through all values of
      ** "x", skipping any NULLs.  */
      Table *pTab = pX->x.pSelect->pSrc->a[0].pTab;
      int iDb = sqlite4SchemaToIndex(db, pTab->pSchema);
      iTab = pX->iTable = pParse->nTab++;
      sqlite4OpenPrimaryKey(pParse, iTab, iDb, pTab, OP_OpenRead);
      iCol = pX->pLeft->iColumn;
    }else{
      /* Set Parse.nQueryLoop to 1 before calling sqlite4CodeSubselect().
      ** This informs the optimizer that there is no point in constructing
      ** any automatic indexes for the outer loop of the sub-select, as it
      ** will only be run once. See also bestAutomaticIndex().  */
      int nQueryLoopSave = pParse->nQueryLoop;
      pParse->nQueryLoop = (double)1;
      sqlite4CodeSubselect(pParse, pX, 0, 0);
      pParse->nQueryLoop = nQueryLoopSave;
      iTab = pX->iTable;
      iCol = 0;
    }
    sqlite4VdbeAddOp2(v, OP_Rewind, iTab, 0);
    assert( pLevel->plan.wsFlags & WHERE_IN_ABLE );





    if( pLevel->u.in.nIn==0 ) pLevel->addrNxt = sqlite4VdbeMakeLabel(v);
    pLevel->u.in.nIn++;
    pLevel->u.in.aInLoop = sqlite4DbReallocOrFree(db, pLevel->u.in.aInLoop, 

        (sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn)
    );
    pIn = pLevel->u.in.aInLoop;

    if( pIn ){
      pIn += pLevel->u.in.nIn - 1;
      pIn->iCur = iTab;
      if( iCol>=0 ){
        pIn->addrInTop = sqlite4VdbeAddOp3(v, OP_Column, iTab, iCol, iReg);
      }else{
        pIn->addrInTop = sqlite4VdbeAddOp2(v, OP_Rowid, iTab, iReg);
      }

      sqlite4VdbeAddOp1(v, OP_IsNull, iReg);
    }else{
      assert( db->mallocFailed );
      pLevel->u.in.nIn = 0;
    }
#endif
  }
  disableTerm(pLevel, pTerm);
  return iReg;
}
................................................................................
** no conversion should be attempted before using a t2.b value as part of
** a key to search the index. Hence the first byte in the returned affinity
** string in this example would be set to SQLITE4_AFF_NONE.
*/
static int codeAllEqualityTerms(
  Parse *pParse,        /* Parsing context */
  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
  WhereClause *pWC,     /* The WHERE clause */
  Bitmask notReady,     /* Which parts of FROM have not yet been coded */
  int nExtraReg,        /* Number of extra registers to allocate */
  char **pzAff          /* OUT: Set to point to affinity string */
){
  int nEq = pLevel->plan.nEq;   /* The number of == or IN constraints to code */
  Vdbe *v = pParse->pVdbe;      /* The vm under construction */
  Index *pIdx;                  /* The index being used for this loop */
  int iCur = pLevel->iTabCur;   /* The cursor of the table */
  WhereTerm *pTerm;             /* A single constraint term */

  int j;                        /* Loop counter */
  int regBase;                  /* Base register */
  int nReg;                     /* Number of registers to allocate */
  char *zAff;                   /* Affinity string to return */

  /* This module is only called on query plans that use an index. */
  assert( pLevel->plan.wsFlags & WHERE_INDEXED );
  pIdx = pLevel->plan.u.pIdx;





  /* Figure out how many memory cells we will need then allocate them.
  */
  regBase = pParse->nMem + 1;
  nReg = pLevel->plan.nEq + nExtraReg;
  pParse->nMem += nReg;

  zAff = sqlite4DbStrDup(pParse->db, sqlite4IndexAffinityStr(v, pIdx));
  if( !zAff ){
    pParse->db->mallocFailed = 1;
  }

  /* Evaluate the equality constraints
  */
  assert( pIdx->nColumn>=nEq );
  for(j=0; j<nEq; j++){
    int r1;
    int k = pIdx->aiColumn[j];
    pTerm = findTerm(pWC, iCur, k, notReady, pLevel->plan.wsFlags, pIdx);
    if( NEVER(pTerm==0) ) break;
    /* The following true for indices with redundant columns. 
    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    r1 = codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
    if( r1!=regBase+j ){
      if( nReg==1 ){
        sqlite4ReleaseTempReg(pParse, regBase);
        regBase = r1;
      }else{
        sqlite4VdbeAddOp2(v, OP_SCopy, r1, regBase+j);
      }
................................................................................
**
**   "a=? AND b>?"
**
** The returned pointer points to memory obtained from sqlite4DbMalloc().
** It is the responsibility of the caller to free the buffer when it is
** no longer required.
*/
static char *explainIndexRange(sqlite4 *db, WhereLevel *pLevel, Table *pTab){
  WherePlan *pPlan = &pLevel->plan;
  Index *pPk;
  Index *pIdx = pPlan->u.pIdx;
  int nEq = pPlan->nEq;
  int i;


  StrAccum txt;

  pPk = sqlite4FindPrimaryKey(pTab, 0);
  if( nEq==0 && (pPlan->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){
    return 0;
  }
  sqlite4StrAccumInit(&txt, 0, 0, SQLITE4_MAX_LENGTH);
  txt.db = db;
  txt.pEnv = db->pEnv;

  sqlite4StrAccumAppend(&txt, " (", 2);
  for(i=0; i<nEq; i++){
    const char *zCol = tblColumnName(pTab, idxColumnNumber(pIdx, pPk, i));
    explainAppendTerm(&txt, i, zCol, "=");
  }


  if( pPlan->wsFlags&WHERE_BTM_LIMIT ){
    const char *zCol = tblColumnName(pTab, idxColumnNumber(pIdx, pPk, nEq));

    explainAppendTerm(&txt, i++, zCol, ">");
  }
  if( pPlan->wsFlags&WHERE_TOP_LIMIT ){
    const char *zCol = tblColumnName(pTab, idxColumnNumber(pIdx, pPk, nEq));

    explainAppendTerm(&txt, i, zCol, "<");
  }
  sqlite4StrAccumAppend(&txt, ")", 1);
  return sqlite4StrAccumFinish(&txt);
}

/*
** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
................................................................................
  SrcList *pTabList,              /* Table list this loop refers to */
  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  int iLevel,                     /* Value for "level" column of output */
  int iFrom,                      /* Value for "from" column of output */
  u16 wctrlFlags                  /* Flags passed to sqlite4WhereBegin() */
){
  if( pParse->explain==2 ){
    u32 flags = pLevel->plan.wsFlags;
    SrcListItem *pItem = &pTabList->a[pLevel->iFrom];
    Vdbe *v = pParse->pVdbe;      /* VM being constructed */
    sqlite4 *db = pParse->db;     /* Database handle */
    char *zMsg;                   /* Text to add to EQP output */
    sqlite4_int64 nRow;           /* Expected number of rows visited by scan */
    int iId = pParse->iSelectId;  /* Select id (left-most output column) */
    int isSearch;                 /* True for a SEARCH. False for SCAN. */





    if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return;

    isSearch = (pLevel->plan.nEq>0)
             || (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0

             || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));

    zMsg = sqlite4MPrintf(db, "%s", isSearch?"SEARCH":"SCAN");
    if( pItem->pSelect ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId);
    }else{
      zMsg = sqlite4MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName);
    }

    if( pItem->zAlias ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
    }
    if( (flags & WHERE_INDEXED)!=0 ){
      char *zWhere = explainIndexRange(db, pLevel, pItem->pTab);
      Index *pIdx = pLevel->plan.u.pIdx;
      const char *zName = "";
      const char *zType = "INDEX";

      if( pIdx->eIndexType==SQLITE4_INDEX_PRIMARYKEY ){
        zType = "PRIMARY KEY";
      }else if( 0==(flags & WHERE_TEMP_INDEX) ){
        zName = pIdx->zName;
      }
      zMsg = sqlite4MAppendf(db, zMsg, "%s USING %s%s%s%s%s", zMsg, 
          ((flags & WHERE_TEMP_INDEX)?"AUTOMATIC ":""),
          zType, (zName[0] ? " " : ""), zName, zWhere
      );
      sqlite4DbFree(db, zWhere);







    }
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
      sqlite4_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
      zMsg = sqlite4MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
                  pVtabIdx->idxNum, pVtabIdx->idxStr);

    }
#endif
    if( wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX) ){
      testcase( wctrlFlags & WHERE_ORDERBY_MIN );
      nRow = 1;
    }else{
      nRow = (sqlite4_int64)pLevel->plan.nRow;
    }
    zMsg = sqlite4MAppendf(db, zMsg, "%s (~%lld rows)", zMsg, nRow);
    sqlite4VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
  }
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE4_OMIT_EXPLAIN */


/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */
  u16 wctrlFlags,      /* One of the WHERE_* flags defined in sqliteInt.h */
  Bitmask notReady,    /* Which tables are currently available */
  Expr *pWhere         /* Complete WHERE clause */
){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */

  int bRev;            /* True if we need to scan in reverse order */
  WhereLevel *pLevel;  /* The where level to be coded */

  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  Parse *pParse;                  /* Parsing context */
  Vdbe *v;                        /* The prepared stmt under constructions */
  SrcListItem *pTabItem;  /* FROM clause term being coded */
  int addrBrk;                    /* Jump here to break out of the loop */
  int addrCont;                   /* Jump here to continue with next cycle */

  int iReleaseReg = 0;            /* Temp register to free before returning */


  pParse = pWInfo->pParse;
  v = pParse->pVdbe;
  pWC = pWInfo->pWC;
  pLevel = &pWInfo->a[iLevel];

  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;
  bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;





  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that
................................................................................
  */
  if( pLevel->iFrom>0 && (pTabItem[0].jointype & JT_LEFT)!=0 ){
    pLevel->iLeftJoin = ++pParse->nMem;
    sqlite4VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

  if( (pLevel->plan.wsFlags & WHERE_INDEXED)
   && (pLevel->plan.u.pIdx->eIndexType==SQLITE4_INDEX_FTS5)
  ){
    /* Case -1:  An FTS query */
    int iTerm;
    int rMatch;
    int rFree;
    findMatchExpr(pParse, pWC, pTabItem, &iTerm);

    rMatch = sqlite4ExprCodeTemp(pParse, pWC->a[iTerm].pExpr->pRight, &rFree);
    pWC->a[iTerm].wtFlags |= TERM_CODED;
    sqlite4Fts5CodeQuery(pParse, 
        pLevel->plan.u.pIdx, pLevel->iIdxCur, addrBrk, rMatch
    );
    sqlite4ReleaseTempReg(pParse, rFree);

    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4VdbeAddOp3(v, OP_SeekPk, iCur, 0, pLevel->iIdxCur);
    pLevel->op = OP_FtsNext;
    pLevel->p1 = pLevel->iIdxCur;
  }else 


#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if(  (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    /* Case 0:  The table is a virtual-table.  Use the VFilter and VNext
    **          to access the data.
    */
    int iReg;   /* P3 Value for OP_VFilter */
    sqlite4_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
    int nConstraint = pVtabIdx->nConstraint;
    struct sqlite4_index_constraint_usage *aUsage =
                                                pVtabIdx->aConstraintUsage;
    const struct sqlite4_index_constraint *aConstraint =
                                                pVtabIdx->aConstraint;

    sqlite4ExprCachePush(pParse);
    iReg = sqlite4GetTempRange(pParse, nConstraint+2);

    for(j=1; j<=nConstraint; j++){



      for(k=0; k<nConstraint; k++){
        if( aUsage[k].argvIndex==j ){
          int iTerm = aConstraint[k].iTermOffset;

          sqlite4ExprCode(pParse, pWC->a[iTerm].pExpr->pRight, iReg+j+1);
          break;
        }
      }
      if( k==nConstraint ) break;
    }
    sqlite4VdbeAddOp2(v, OP_Integer, pVtabIdx->idxNum, iReg);
    sqlite4VdbeAddOp2(v, OP_Integer, j-1, iReg+1);
    sqlite4VdbeAddOp4(v, OP_VFilter, iCur, addrBrk, iReg, pVtabIdx->idxStr,

                      pVtabIdx->needToFreeIdxStr ? P4_MPRINTF : P4_STATIC);
    pVtabIdx->needToFreeIdxStr = 0;

    for(j=0; j<nConstraint; j++){
      if( aUsage[j].omit ){
        int iTerm = aConstraint[j].iTermOffset;

        disableTerm(pLevel, &pWC->a[iTerm]);
      }
    }
    pLevel->op = OP_VNext;
    pLevel->p1 = iCur;
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite4ExprCachePop(pParse, 1);
  }else
#endif /* SQLITE4_OMIT_VIRTUALTABLE */


  if( pLevel->plan.wsFlags & (WHERE_COLUMN_RANGE|WHERE_COLUMN_EQ) ){










































































































    /* Case 3: A scan using an index.
    **
    **         The WHERE clause may contain zero or more equality 
    **         terms ("==" or "IN" operators) that refer to the N
    **         left-most columns of the index. It may also contain
    **         inequality constraints (>, <, >= or <=) on the indexed
    **         column that immediately follows the N equalities. Only 
    **         the right-most column can be an inequality - the rest must
................................................................................
      OP_Noop,             /* 0: (!end_constraints) */
      OP_IdxGE,            /* 1: (end_constraints && !endEq && !bRev) */
      OP_IdxLE,            /* 2: (end_constraints && !endEq &&  bRev) */
      OP_IdxGT,            /* 3: (end_constraints &&  endEq && !bRev) */
      OP_IdxLT             /* 4: (end_constraints &&  endEq &&  bRev) */
    };

    int nEq = pLevel->plan.nEq;  /* Number of == or IN terms */
    int isMinQuery = 0;          /* If this is an optimized SELECT min(x).. */
    int regBase;                 /* Base register holding constraint values */
    int r1;                      /* Temp register */
    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
    int startEq;                 /* True if range start uses ==, >= or <= */
    int endEq;                   /* True if range end uses ==, >= or <= */
    int start_constraints;       /* Start of range is constrained */
................................................................................
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff;               /* Affinity for end of range constraint */
    int regEndKey;               /* Register for end-key */
    int iIneq;                   /* The table column subject to inequality */
    Index *pPk;                  /* Primary key index on same table as pIdx */

    pIdx = pLevel->plan.u.pIdx;
    pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    iIneq = idxColumnNumber(pIdx, pPk, nEq);
    iIdxCur = pLevel->iIdxCur;
    assert( iCur==pLevel->iTabCur );

    /* If this loop satisfies a sort order (pOrderBy) request that 
    ** was passed to this function to implement a "SELECT min(x) ..." 
    ** query, then the caller will only allow the loop to run for
    ** a single iteration. This means that the first row returned
    ** should not have a NULL value stored in 'x'. If column 'x' is
    ** the first one after the nEq equality constraints in the index,
    ** this requires some special handling.
    */
    if( (wctrlFlags&WHERE_ORDERBY_MIN)!=0
     && (pLevel->plan.wsFlags&WHERE_ORDERBY)
     && (pIdx->nColumn>nEq)
    ){
      /* assert( pOrderBy->nExpr==1 ); */
      /* assert( pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq] ); */
      isMinQuery = 1;
      nExtraReg = 1;
    }

    /* Find any inequality constraint terms for the start and end 
    ** of the range.  */


    if( pLevel->plan.wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = findTerm(pWC, iCur, iIneq, notReady, (WO_LT|WO_LE), pIdx);

      nExtraReg = 1;
    }
    if( pLevel->plan.wsFlags & WHERE_BTM_LIMIT ){
      pRangeStart = findTerm(pWC, iCur, iIneq, notReady, (WO_GT|WO_GE), pIdx);

      nExtraReg = 1;
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase. Ensure that nExtraReg registers are allocated
    ** immediately following the array.
    */
    regBase = codeAllEqualityTerms(
        pParse, pLevel, pWC, notReady, nExtraReg, &zStartAff
    );
    assert( (regBase+nEq+nExtraReg-1)<=pParse->nMem );

    zEndAff = sqlite4DbStrDup(pParse->db, zStartAff);
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).  */

    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE4_SO_ASC))
     || (bRev && pIdx->nColumn==nEq)
    ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
    }

    testcase( pRangeStart && pRangeStart->eOperator & WO_LE );
    testcase( pRangeStart && pRangeStart->eOperator & WO_GE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_LE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_GE );
    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
    start_constraints = pRangeStart || nEq>0;

    /* Seek the index cursor to the start of the range. */
    nConstraint = nEq;
    if( pRangeStart ){
................................................................................
    testcase( op==OP_Rewind );
    testcase( op==OP_Last );
    testcase( op==OP_SeekGt );
    testcase( op==OP_SeekGe );
    testcase( op==OP_SeekLe );
    testcase( op==OP_SeekLt );
    sqlite4VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
    if( (pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn))>nEq ){
      sqlite4VdbeChangeP5(v, OPFLAG_PARTIALKEY);
    }

    /* Set variable op to the instruction required to determine if the
    ** cursor is passed the end of the range. If the range is unbounded,
    ** then set op to OP_Noop. Nothing to do in this case.  */
    assert( (endEq==0 || endEq==1) );
................................................................................
    testcase( op==OP_Noop );
    testcase( op==OP_IdxGE );
    testcase( op==OP_IdxLT );
    testcase( op==OP_IdxLE );
    testcase( op==OP_IdxGT );

    if( op!=OP_Noop ){
      /* If there is an inequality at the end of this range, compute its
      ** value here.  */

      nConstraint = nEq;
      if( pRangeEnd ){
        Expr *pRight = pRangeEnd->pExpr->pRight;
        sqlite4ExprCacheRemove(pParse, regBase+nEq, 1);
        sqlite4ExprCode(pParse, pRight, regBase+nEq);
        if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
          sqlite4ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
        }
        if( zEndAff ){
          if( sqlite4CompareAffinity(pRight, zEndAff[nEq])==SQLITE4_AFF_NONE){
            /* Since the comparison is to be performed with no conversions
             ** applied to the operands, set the affinity to apply to pRight to 
             ** SQLITE4_AFF_NONE.  */
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
          if( sqlite4ExprNeedsNoAffinityChange(pRight, zEndAff[nEq]) ){
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
        }  
        codeApplyAffinity(pParse, regBase, nEq+1, zEndAff);
................................................................................
      }

      /* Now compute an end-key using OP_MakeIdxKey */
      regEndKey = ++pParse->nMem;
      sqlite4VdbeAddOp4Int(
          v, OP_MakeIdxKey, iIdxCur, regBase, regEndKey, nConstraint
      );

    }

    sqlite4DbFree(pParse->db, zStartAff);
    sqlite4DbFree(pParse->db, zEndAff);

    /* Top of the loop body */
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
................................................................................
    if( pIdx->eIndexType!=SQLITE4_INDEX_PRIMARYKEY
     && pIdx->eIndexType!=SQLITE4_INDEX_TEMP
    ){
      sqlite4VdbeAddOp3(v, OP_SeekPk, iCur, 0, iIdxCur);
    }

    /* If there are inequality constraints, check that the value
    ** of the table column that the inequality constrains is not NULL.
    ** If it is, jump to the next iteration of the loop.  */

    r1 = sqlite4GetTempReg(pParse);
    testcase( pLevel->plan.wsFlags & WHERE_BTM_LIMIT );
    testcase( pLevel->plan.wsFlags & WHERE_TOP_LIMIT );
    if( (pLevel->plan.wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 ){
      sqlite4ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iIneq, r1);
      sqlite4VdbeAddOp2(v, OP_IsNull, r1, addrCont);
    }
    sqlite4ReleaseTempReg(pParse, r1);

    /* Record the instruction used to terminate the loop. Disable 
    ** WHERE clause terms made redundant by the index range scan.
    */
    if( pLevel->plan.wsFlags & WHERE_UNIQUE ){
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;





  }else

#ifndef SQLITE4_OMIT_OR_OPTIMIZATION
  if( pLevel->plan.wsFlags & WHERE_MULTI_OR ){
    /* Case 4:  Two or more separately indexed terms connected by OR
    **
    ** Example:
    **
    **   CREATE TABLE t1(a,b,c,d);
    **   CREATE INDEX i1 ON t1(a);
    **   CREATE INDEX i2 ON t1(b);
    **   CREATE INDEX i3 ON t1(c);
................................................................................
    **          Return     2                # Jump back to the Gosub
    **
    **       B: <after the loop>
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */



    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regKeyset = 0;                        /* Register for RowSet object */
    int regKey = 0;                           /* Register holding key */
    int iLoopBody = sqlite4VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
   
    pTerm = pLevel->plan.u.pTerm;
    assert( pTerm!=0 );
    assert( pTerm->eOperator==WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList in pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite4WhereBegin().
    */
    if( pWInfo->nLevel>1 ){
      int nNotReady;                 /* The number of notReady tables */
      SrcListItem *origSrc;     /* Original list of tables */
      nNotReady = pWInfo->nLevel - iLevel - 1;
      pOrTab = sqlite4StackAllocRaw(pParse->db,
                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
      if( pOrTab==0 ) return notReady;
      pOrTab->nAlloc = (i16)(nNotReady + 1);
      pOrTab->nSrc = pOrTab->nAlloc;
      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
      origSrc = pWInfo->pTabList->a;
      for(k=1; k<=nNotReady; k++){
        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
      }
    }else{
      pOrTab = pWInfo->pTabList;
    }

    /* Initialize the keyset register to contain NULL. An SQL NULL is 
    ** equivalent to an empty rowset.
    **
    ** Also initialize regReturn to contain the address of the instruction 
    ** immediately following the OP_Return at the bottom of the loop. This
    ** is required in a few obscure LEFT JOIN cases where control jumps
    ** over the top of the loop into the body of it. In this case the 
    ** correct response for the end-of-loop code (the OP_Return) is to 
    ** fall through to the next instruction, just as an OP_Next does if
    ** called on an uninitialized cursor.
    */
    if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
      regKeyset = ++pParse->nMem;
      regKey = ++pParse->nMem;
      sqlite4VdbeAddOp2(v, OP_Null, 0, regKeyset);
    }
    iRetInit = sqlite4VdbeAddOp2(v, OP_Integer, 0, regReturn);

    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
    ** Then for every term xN, evaluate as the subexpression: xN AND z
    ** That way, terms in y that are factored into the disjunction will
    ** be picked up by the recursive calls to sqlite4WhereBegin() below.









    */
    if( pWC->nTerm>1 ){







      pAndExpr = sqlite4ExprAlloc(pParse->db, TK_AND, 0, 0);

      pAndExpr->pRight = pWhere;


    }

    for(ii=0; ii<pOrWc->nTerm; ii++){
      WhereTerm *pOrTerm = &pOrWc->a[ii];
      if( pOrTerm->leftCursor==iCur || pOrTerm->eOperator==WO_AND ){
        WhereInfo *pSubWInfo;          /* Info for single OR-term scan */
        Expr *pOrExpr = pOrTerm->pExpr;
        if( pAndExpr ){
          pAndExpr->pLeft = pOrExpr;
          pOrExpr = pAndExpr;
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_NO_AUTOINDEX | WHERE_ONETABLE_ONLY);

        if( pSubWInfo ){

          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int addrJump;
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
            addrJump = sqlite4VdbeCurrentAddr(v) + 2;
            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, 
                regKeyset, addrJump, regKey, ((ii==pOrWc->nTerm-1)?-1:ii)
            );

          }
          sqlite4VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.
          */
          if( pSubWInfo->untestedTerms ) untestedTerms = 1;


























          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite4WhereEnd(pSubWInfo);
        }
      }
    }




    sqlite4DbFree(pParse->db, pAndExpr);

    sqlite4VdbeChangeP1(v, iRetInit, sqlite4VdbeCurrentAddr(v));
    sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite4VdbeResolveLabel(v, iLoopBody);

    if( pWInfo->nLevel>1 ) sqlite4StackFree(pParse->db, pOrTab);
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */

  {



    /* Case 5:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );
    pLevel->op = aStep[bRev];
    pLevel->p1 = iCur;
    pLevel->p2 = 1 + sqlite4VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
    pLevel->p5 = SQLITE4_STMTSTATUS_FULLSCAN_STEP;
  }
  notReady &= ~getMask(pWC->pMaskSet, iCur);

  /* Insert code to test every subexpression that can be completely
  ** computed using the current set of tables.
  **
  ** IMPLEMENTATION-OF: R-49525-50935 Terms that cannot be satisfied through
  ** the use of indices become tests that are evaluated against each row of
  ** the relevant input tables.
  */
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
    testcase( pTerm->wtFlags & TERM_CODED );
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->prereqAll & notReady)!=0 ){
      testcase( pWInfo->untestedTerms==0
               && (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
      pWInfo->untestedTerms = 1;
      continue;
    }
    pE = pTerm->pExpr;
    assert( pE!=0 );
    if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
      continue;
    }
    sqlite4ExprIfFalse(pParse, pE, addrCont, SQLITE4_JUMPIFNULL);
    pTerm->wtFlags |= TERM_CODED;
  }































  /* For a LEFT OUTER JOIN, generate code that will record the fact that
  ** at least one row of the right table has matched the left table.  
  */
  if( pLevel->iLeftJoin ){
    pLevel->addrFirst = sqlite4VdbeCurrentAddr(v);
    sqlite4VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
    VdbeComment((v, "record LEFT JOIN hit"));
    sqlite4ExprCacheClear(pParse);
    for(pTerm=pWC->a, j=0; j<pWC->nTerm; j++, pTerm++){
      testcase( pTerm->wtFlags & TERM_VIRTUAL );  /* IMP: R-30575-11662 */
      testcase( pTerm->wtFlags & TERM_CODED );
      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
      if( (pTerm->prereqAll & notReady)!=0 ){
        assert( pWInfo->untestedTerms );
        continue;
      }
      assert( pTerm->pExpr );
      sqlite4ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE4_JUMPIFNULL);
      pTerm->wtFlags |= TERM_CODED;
    }
  }
  sqlite4ReleaseTempReg(pParse, iReleaseReg);

  return notReady;
}






























































































#if defined(SQLITE4_TEST)


/*
** The following variable holds a text description of query plan generated
** by the most recent call to sqlite4WhereBegin().  Each call to WhereBegin
** overwrites the previous.  This information is used for testing and
** analysis only.

*/
char sqlite4_query_plan[BMS*2*40];  /* Text of the join */
static int nQPlan = 0;              /* Next free slow in _query_plan[] */










#endif /* SQLITE4_TEST */


/*








** Free a WhereInfo structure
*/
static void whereInfoFree(sqlite4 *db, WhereInfo *pWInfo){
  if( ALWAYS(pWInfo) ){




























































































































































































































































































































































































    int i;
    for(i=0; i<pWInfo->nLevel; i++){







































































































































































      sqlite4_index_info *pInfo = pWInfo->a[i].pIdxInfo;
      if( pInfo ){










































































        /* assert( pInfo->needToFreeIdxStr==0 || db->mallocFailed ); */























































        if( pInfo->needToFreeIdxStr ){









          sqlite4_free(db->pEnv, pInfo->idxStr);

        }





        sqlite4DbFree(db, pInfo);

      }


































































































































































































































































      if( pWInfo->a[i].plan.wsFlags & WHERE_TEMP_INDEX ){
        Index *pIdx = pWInfo->a[i].plan.u.pIdx;







































        if( pIdx ){
          assert( pIdx->eIndexType==SQLITE4_INDEX_TEMP );
          sqlite4DbFree(db, pIdx->zColAff);






























































































































































































































































































































          sqlite4DbFree(db, pIdx);

        }
      }






    }
    whereClauseClear(pWInfo->pWC);






























    sqlite4DbFree(db, pWInfo);

  }
}




















































































/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite4WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
................................................................................
**
** Note that the loops might not be nested in the order in which they
** appear in the FROM clause if a different order is better able to make
** use of indices.  Note also that when the IN operator appears in
** the WHERE clause, it might result in additional nested loops for
** scanning through all values on the right-hand side of the IN.
**
** There are cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite4WhereEnd() generates the code to close them.
**
** The code that sqlite4WhereBegin() generates leaves the cursors named
** in pTabList pointing at their appropriate entries.  The [...] code
** can use OP_Column and OP_Rowid opcodes on these cursors to extract
................................................................................
**        move the row2 cursor to a null row
**        goto start
**      fi
**    end
**
** ORDER BY CLAUSE PROCESSING
**
** *ppOrderBy is a pointer to the ORDER BY clause of a SELECT statement,

** if there is one.  If there is no ORDER BY clause or if this routine
** is called from an UPDATE or DELETE statement, then ppOrderBy is NULL.
**
** If an index can be used so that the natural output order of the table
** scan is correct for the ORDER BY clause, then that index is used and
** *ppOrderBy is set to NULL.  This is an optimization that prevents an
** unnecessary sort of the result set if an index appropriate for the
** ORDER BY clause already exists.
**
** If the where clause loops cannot be arranged to provide the correct
** output order, then the *ppOrderBy is unchanged.
*/
WhereInfo *sqlite4WhereBegin(
  Parse *pParse,        /* The parser context */
  SrcList *pTabList,    /* A list of all tables to be scanned */
  Expr *pWhere,         /* The WHERE clause */
  ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
  ExprList *pDistinct,  /* The select-list for DISTINCT queries - or NULL */
  u16 wctrlFlags        /* One of the WHERE_* flags defined in sqliteInt.h */

){
  int i;                     /* Loop counter */
  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  Bitmask notReady;          /* Cursors that are not yet positioned */

  WhereMaskSet *pMaskSet;    /* The expression mask set */
  WhereClause *pWC;               /* Decomposition of the WHERE clause */
  SrcListItem *pTabItem;  /* A single entry from pTabList */
  WhereLevel *pLevel;             /* A single level in the pWInfo list */

  int iFrom;                      /* First unused FROM clause element */
  int andFlags;              /* AND-ed combination of all pWC->a[].wtFlags */
  sqlite4 *db;               /* Database connection */
















  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask 
  */
  testcase( pTabList->nSrc==BMS );
  if( pTabList->nSrc>BMS ){
    sqlite4ErrorMsg(pParse, "at most %d tables in a join", BMS);
................................................................................
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value. A single allocation is used to store the WhereInfo
  ** struct, the contents of WhereInfo.a[], the WhereClause structure
  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
  ** some architectures. Hence the ROUND8() below.
  */
  db = pParse->db;
  nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
  pWInfo = sqlite4DbMallocZero(db, 
      nByteWInfo + 
      sizeof(WhereClause) +
      sizeof(WhereMaskSet)
  );
  if( db->mallocFailed ){
    sqlite4DbFree(db, pWInfo);
    pWInfo = 0;
    goto whereBeginError;
  }
  pWInfo->nLevel = nTabList;
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;


  pWInfo->iBreak = sqlite4VdbeMakeLabel(v);
  pWInfo->pWC = pWC = (WhereClause *)&((u8 *)pWInfo)[nByteWInfo];
  pWInfo->wctrlFlags = wctrlFlags;
  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
  pMaskSet = (WhereMaskSet*)&pWC[1];


  /* Disable the DISTINCT optimization if SQLITE4_DistinctOpt is set via
  ** sqlite4_test_ctrl(SQLITE4_TESTCTRL_OPTIMIZATIONS,...) */
  if( db->flags & SQLITE4_DistinctOpt ) pDistinct = 0;





  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  whereClauseInit(pWC, pParse, pMaskSet, wctrlFlags);
  sqlite4ExprCodeConstants(pParse, pWhere);
  whereSplit(pWC, pWhere, TK_AND);   /* IMP: R-15842-53296 */

    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (nTabList==0 || sqlite4ExprIsConstantNotJoin(pWhere)) ){
    sqlite4ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE4_JUMPIFNULL);
    pWhere = 0;
  }










  /* Assign a bit from the bitmask to every term in the FROM clause.
  **
  ** When assigning bitmask values to FROM clause cursors, it must be
  ** the case that if X is the bitmask for the N-th FROM clause term then
  ** the bitmask for all FROM clause terms to the left of the N-th term
  ** is (X-1).   An expression from the ON clause of a LEFT JOIN can use
  ** its Expr.iRightJoinTable value to find the bitmask of the right table
  ** of the join.  Subtracting one from the right table bitmask gives a
  ** bitmask for all tables to the left of the join.  Knowing the bitmask
  ** for all tables to the left of a left join is important.  Ticket #3015.
  **
  ** Configure the WhereClause.vmask variable so that bits that correspond
  ** to virtual table cursors are set. This is used to selectively disable 
  ** the OR-to-IN transformation in exprAnalyzeOrTerm(). It is not helpful 
  ** with virtual tables.
  **
  ** Note that bitmasks are created for all pTabList->nSrc tables in
  ** pTabList, not just the first nTabList tables.  nTabList is normally
  ** equal to pTabList->nSrc but might be shortened to 1 if the
  ** WHERE_ONETABLE_ONLY flag is set.
  */
  assert( pWC->vmask==0 && pMaskSet->n==0 );
  for(i=0; i<pTabList->nSrc; i++){
    createMask(pMaskSet, pTabList->a[i].iCursor);
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( ALWAYS(pTabList->a[i].pTab) && IsVirtual(pTabList->a[i].pTab) ){
      pWC->vmask |= ((Bitmask)1 << i);
    }
#endif
  }
#ifndef NDEBUG
  {
    Bitmask toTheLeft = 0;
    for(i=0; i<pTabList->nSrc; i++){
      Bitmask m = getMask(pMaskSet, pTabList->a[i].iCursor);
      assert( (m-1)==toTheLeft );
      toTheLeft |= m;
    }
  }
#endif

  /* Analyze all of the subexpressions. */




  exprAnalyzeAll(pTabList, pWC);
  if( db->mallocFailed ){
    goto whereBeginError;
  }

  /* Check if the DISTINCT qualifier, if there is one, is redundant. 
  ** If it is, then set pDistinct to NULL and WhereInfo.eDistinct to
  ** WHERE_DISTINCT_UNIQUE to tell the caller to ignore the DISTINCT.
  */
  if( pDistinct && isDistinctRedundant(pParse, pTabList, pWC, pDistinct) ){
    pDistinct = 0;
    pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;





  }

  /* Chose the best index to use for each table in the FROM clause.
  **
  ** This loop fills in the following fields:
  **
  **   pWInfo->a[].pIdx      The index to use for this level of the loop.
  **   pWInfo->a[].wsFlags   WHERE_xxx flags associated with pIdx
  **   pWInfo->a[].nEq       The number of == and IN constraints


  **   pWInfo->a[].iFrom     Which term of the FROM clause is being coded
  **   pWInfo->a[].iTabCur   The VDBE cursor for the database table
  **   pWInfo->a[].iIdxCur   The VDBE cursor for the index
  **   pWInfo->a[].pTerm     When wsFlags==WO_OR, the OR-clause term
  **

  ** This loop also figures out the nesting order of tables in the FROM
  ** clause.
  */
  notReady = ~(Bitmask)0;
  andFlags = ~0;
  WHERETRACE(("*** Optimizer Start ***\n"));
  for(i=iFrom=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
    WhereCost bestPlan;         /* Most efficient plan seen so far */
    Index *pIdx;                /* Index for FROM table at pTabItem */
    int j;                      /* For looping over FROM tables */
    int bestJ = -1;             /* The value of j */
    Bitmask m;                  /* Bitmask value for j or bestJ */
    int isOptimal;              /* Iterator for optimal/non-optimal search */
    int nUnconstrained;         /* Number tables without INDEXED BY */
    Bitmask notIndexed;         /* Mask of tables that cannot use an index */


    memset(&bestPlan, 0, sizeof(bestPlan));
    bestPlan.rCost = SQLITE4_BIG_DBL;
    WHERETRACE(("*** Begin search for loop %d ***\n", i));

    /* Loop through the remaining entries in the FROM clause to find the
    ** next nested loop. The loop tests all FROM clause entries
    ** either once or twice. 
    **
    ** The first test is always performed if there are two or more entries
    ** remaining and never performed if there is only one FROM clause entry
    ** to choose from.  The first test looks for an "optimal" scan.  In
    ** this context an optimal scan is one that uses the same strategy
    ** for the given FROM clause entry as would be selected if the entry
    ** were used as the innermost nested loop.  In other words, a table
    ** is chosen such that the cost of running that table cannot be reduced
    ** by waiting for other tables to run first.  This "optimal" test works
    ** by first assuming that the FROM clause is on the inner loop and finding
    ** its query plan, then checking to see if that query plan uses any
    ** other FROM clause terms that are notReady.  If no notReady terms are
    ** used then the "optimal" query plan works.
    **
    ** Note that the WhereCost.nRow parameter for an optimal scan might
    ** not be as small as it would be if the table really were the innermost
    ** join.  The nRow value can be reduced by WHERE clause constraints
    ** that do not use indices.  But this nRow reduction only happens if the
    ** table really is the innermost join.  
    **
    ** The second loop iteration is only performed if no optimal scan
    ** strategies were found by the first iteration. This second iteration
    ** is used to search for the lowest cost scan overall.
    **
    ** Previous versions of SQLite performed only the second iteration -
    ** the next outermost loop was always that with the lowest overall
    ** cost. However, this meant that SQLite could select the wrong plan
    ** for scripts such as the following:
    **   
    **   CREATE TABLE t1(a, b); 
    **   CREATE TABLE t2(c, d);
    **   SELECT * FROM t2, t1 WHERE t2.rowid = t1.a;
    **
    ** The best strategy is to iterate through table t1 first. However it
    ** is not possible to determine this with a simple greedy algorithm.
    ** Since the cost of a linear scan through table t2 is the same 
    ** as the cost of a linear scan through table t1, a simple greedy 
    ** algorithm may choose to use t2 for the outer loop, which is a much
    ** costlier approach.
    */
    nUnconstrained = 0;
    notIndexed = 0;
    for(isOptimal=(iFrom<nTabList-1); isOptimal>=0 && bestJ<0; isOptimal--){
      Bitmask mask;             /* Mask of tables not yet ready */
      for(j=iFrom, pTabItem=&pTabList->a[j]; j<nTabList; j++, pTabItem++){
        int doNotReorder;    /* True if this table should not be reordered */
        WhereCost sCost;     /* Cost information from best[Virtual]Index() */
        ExprList *pOrderBy;  /* ORDER BY clause for index to optimize */
        ExprList *pDist;     /* DISTINCT clause for index to optimize */
  
        doNotReorder =  (pTabItem->jointype & (JT_LEFT|JT_CROSS))!=0;
        if( j!=iFrom && doNotReorder ) break;
        m = getMask(pMaskSet, pTabItem->iCursor);
        if( (m & notReady)==0 ){
          if( j==iFrom ) iFrom++;
          continue;





        }
        mask = (isOptimal ? m : notReady);
        pOrderBy = ((i==0 && ppOrderBy )?*ppOrderBy:0);
        pDist = (i==0 ? pDistinct : 0);
        if( pTabItem->pIndex==0 ) nUnconstrained++;










  
        WHERETRACE(("=== trying table %d with isOptimal=%d ===\n",
                    j, isOptimal));
        assert( pTabItem->pTab );

        if( bestMatchIdx(pParse, pWC, pTabItem, notReady, &sCost) ){
          /* no-op */
        }else
#ifndef SQLITE4_OMIT_VIRTUALTABLE
        if( IsVirtual(pTabItem->pTab) ){
          sqlite4_index_info **pp = &pWInfo->a[j].pIdxInfo;
          bestVirtualIndex(pParse, pWC, pTabItem, mask, notReady, pOrderBy,
                           &sCost, pp);
        }else 
#endif
        {
          bestKVIndex(pParse, pWC, pTabItem, mask, notReady, pOrderBy,
              pDist, &sCost);





        }

        assert( isOptimal || (sCost.used&notReady)==0 );



        /* If an INDEXED BY clause is present, then the plan must use that
        ** index if it uses any index at all */
        assert( pTabItem->pIndex==0 
                  || (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0
                  || sCost.plan.u.pIdx==pTabItem->pIndex );



        if( isOptimal && (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ){
          notIndexed |= m;






        }





        /* Conditions under which this table becomes the best so far:
        **
        **   (1) The table must not depend on other tables that have not
        **       yet run.
        **
        **   (2) A full-table-scan plan cannot supercede indexed plan unless
        **       the full-table-scan is an "optimal" plan as defined above.
        **
        **   (3) All tables have an INDEXED BY clause or this table lacks an
        **       INDEXED BY clause or this table uses the specific
        **       index specified by its INDEXED BY clause.  This rule ensures
        **       that a best-so-far is always selected even if an impossible
        **       combination of INDEXED BY clauses are given.  The error
        **       will be detected and relayed back to the application later.
        **       The NEVER() comes about because rule (2) above prevents
        **       An indexable full-table-scan from reaching rule (3).
        **
        **   (4) The plan cost must be lower than prior plans or else the
        **       cost must be the same and the number of rows must be lower.
        */
        if( (sCost.used&notReady)==0                       /* (1) */
            && (bestJ<0 || (notIndexed&m)!=0               /* (2) */
                || (bestPlan.plan.wsFlags & WHERE_NOT_FULLSCAN)==0
                || (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0)
            && (nUnconstrained==0 || pTabItem->pIndex==0   /* (3) */
                || NEVER((sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0))
            && (bestJ<0 || sCost.rCost<bestPlan.rCost      /* (4) */
                || (sCost.rCost<=bestPlan.rCost 
                 && sCost.plan.nRow<bestPlan.plan.nRow))
        ){
          WHERETRACE(("=== table %d is best so far"
                      " with cost=%g and nRow=%g\n",
                      j, sCost.rCost, sCost.plan.nRow));
          bestPlan = sCost;
          bestJ = j;



        }


        if( doNotReorder ) break;
      }
    }
    assert( bestJ>=0 );
    assert( notReady & getMask(pMaskSet, pTabList->a[bestJ].iCursor) );
    WHERETRACE(("*** Optimizer selects table %d for loop %d"
                " with cost=%g and nRow=%g\n",
                bestJ, pLevel-pWInfo->a, bestPlan.rCost, bestPlan.plan.nRow));
    /* The ALWAYS() that follows was added to hush up clang scan-build */
    if( (bestPlan.plan.wsFlags & WHERE_ORDERBY)!=0 && ALWAYS(ppOrderBy) ){
      *ppOrderBy = 0;



    }
    if( (bestPlan.plan.wsFlags & WHERE_DISTINCT)!=0 ){
      assert( pWInfo->eDistinct==0 );
      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
    }
    andFlags &= bestPlan.plan.wsFlags;
    pLevel->plan = bestPlan.plan;













    testcase( bestPlan.plan.wsFlags & WHERE_INDEXED );
    testcase( bestPlan.plan.wsFlags & WHERE_TEMP_INDEX );
    if( bestPlan.plan.wsFlags & (WHERE_INDEXED|WHERE_TEMP_INDEX) ){
      pLevel->iIdxCur = pParse->nTab++;
    }else{
      pLevel->iIdxCur = -1;


    }
    notReady &= ~getMask(pMaskSet, pTabList->a[bestJ].iCursor);
    pLevel->iFrom = (u8)bestJ;
    if( bestPlan.plan.nRow>=(double)1 ){
      pParse->nQueryLoop *= bestPlan.plan.nRow;







    }

    /* Check that if the table scanned by this loop iteration had an
    ** INDEXED BY clause attached to it, that the named index is being
    ** used for the scan. If not, then query compilation has failed.
    ** Return an error.
    */



    pIdx = pTabList->a[bestJ].pIndex;
    if( pIdx ){
      if( (bestPlan.plan.wsFlags & WHERE_INDEXED)==0 ){
        sqlite4ErrorMsg(pParse, "cannot use index: %s", pIdx->zName);
        goto whereBeginError;
      }else{
        /* If an INDEXED BY clause is used, the bestIndex() function is
        ** guaranteed to find the index specified in the INDEXED BY clause
        ** if it find an index at all. */
        assert( bestPlan.plan.u.pIdx==pIdx );
      }
    }
  }
  WHERETRACE(("*** Optimizer Finished ***\n"));
  if( pParse->nErr || db->mallocFailed ){
    goto whereBeginError;
  }

  /* If the total query only selects a single row, then the ORDER BY
  ** clause is irrelevant.
  */
  if( (andFlags & WHERE_UNIQUE)!=0 && ppOrderBy ){
    *ppOrderBy = 0;
  }


  /* If the caller is an UPDATE or DELETE statement that is requesting
  ** to use a one-pass algorithm, determine if this is appropriate.
  ** The one-pass algorithm only works if the WHERE clause constraints
  ** the statement to update a single row.
  */
  assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
  if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 && (andFlags & WHERE_UNIQUE)!=0 ){

    pWInfo->okOnePass = 1;
    pWInfo->a[0].plan.wsFlags &= ~WHERE_IDX_ONLY;
  }

  /* Open all tables in the pTabList and any indices selected for
  ** searching those tables.
  */
  sqlite4CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
  notReady = ~(Bitmask)0;
  pWInfo->nRowOut = (double)1;
  for(i=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
    Table *pTab;     /* Table to open */
    int iDb;         /* Index of database containing table/index */


    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;
    pLevel->iTabCur = pTabItem->iCursor;
    pWInfo->nRowOut *= pLevel->plan.nRow;
    iDb = sqlite4SchemaToIndex(db, pTab->pSchema);

    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
      /* Do nothing */
    }else
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
      const char *pVTab = (const char *)sqlite4GetVTable(db, pTab);
      int iCur = pTabItem->iCursor;
      sqlite4VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);


    }else
#endif
    if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
      sqlite4OpenPrimaryKey(pParse, pTabItem->iCursor, iDb, pTab, op);
      testcase( pTab->nCol==BMS-1 );
      testcase( pTab->nCol==BMS );








    }







#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
    if( (pLevel->plan.wsFlags & WHERE_TEMP_INDEX)!=0 ){

      constructAutomaticIndex(pParse, pWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
      Index *pIx = pLevel->plan.u.pIdx;
      if( pIx->eIndexType==SQLITE4_INDEX_PRIMARYKEY ){
        pLevel->iIdxCur = pTabItem->iCursor;

      }else if( pIx->eIndexType!=SQLITE4_INDEX_FTS5 ){
        KeyInfo *pKey = sqlite4IndexKeyinfo(pParse, pIx);

        int iIdxCur = pLevel->iIdxCur;
        assert( pIx->pSchema==pTab->pSchema );
        assert( iIdxCur>=0 );
        sqlite4VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIx->tnum, iDb,
            (char*)pKey, P4_KEYINFO_HANDOFF);
        VdbeComment((v, "%s", pIx->zName));
      }
    }
    sqlite4CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(pWC->pMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite4VdbeCurrentAddr(v);
  if( db->mallocFailed ) goto whereBeginError;

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
  ** program.
  */
  notReady = ~(Bitmask)0;
  for(i=0; i<nTabList; i++){
    pLevel = &pWInfo->a[i];
    explainOneScan(pParse, pTabList, pLevel, i, pLevel->iFrom, wctrlFlags);
    notReady = codeOneLoopStart(pWInfo, i, wctrlFlags, notReady, pWhere);
    pWInfo->iContinue = pLevel->addrCont;
  }

#ifdef SQLITE4_TEST  /* For testing and debugging use only */
  /* Record in the query plan information about the current table
  ** and the index used to access it (if any).  If the table itself
  ** is not used, its name is just '{}'.  If no index is used
  ** the index is listed as "{}".  If the primary key is used the
  ** index name is '*'.
  */
  for(i=0; i<nTabList; i++){
    char *z;
    int n;
    pLevel = &pWInfo->a[i];
    pTabItem = &pTabList->a[pLevel->iFrom];
    z = pTabItem->zAlias;
    if( z==0 ) z = pTabItem->pTab->zName;
    n = sqlite4Strlen30(z);
    if( n+nQPlan < sizeof(sqlite4_query_plan)-10 ){
      if( pLevel->plan.wsFlags & WHERE_IDX_ONLY ){
        memcpy(&sqlite4_query_plan[nQPlan], "{}", 2);
        nQPlan += 2;
      }else{
        memcpy(&sqlite4_query_plan[nQPlan], z, n);
        nQPlan += n;
      }
      sqlite4_query_plan[nQPlan++] = ' ';
    }
    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
      n = sqlite4Strlen30(pLevel->plan.u.pIdx->zName);
      if( n+nQPlan < sizeof(sqlite4_query_plan)-2 ){
        memcpy(&sqlite4_query_plan[nQPlan], pLevel->plan.u.pIdx->zName, n);
        nQPlan += n;
        sqlite4_query_plan[nQPlan++] = ' ';
      }
    }else{
      memcpy(&sqlite4_query_plan[nQPlan], "{} ", 3);
      nQPlan += 3;
    }
  }
  while( nQPlan>0 && sqlite4_query_plan[nQPlan-1]==' ' ){
    sqlite4_query_plan[--nQPlan] = 0;
  }
  sqlite4_query_plan[nQPlan] = 0;
  nQPlan = 0;
#endif /* SQLITE4_TEST // Testing and debugging use only */

  /* Record the continuation address in the WhereInfo structure. Then
  ** clean up and return.
  */
  return pWInfo;

  /* Jump here if malloc fails */
whereBeginError:
  if( pWInfo ){
    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
    whereInfoFree(db, pWInfo);
................................................................................
** sqlite4WhereBegin() for additional information.
*/
void sqlite4WhereEnd(WhereInfo *pWInfo){
  Parse *pParse = pWInfo->pParse;
  Vdbe *v = pParse->pVdbe;
  int i;
  WhereLevel *pLevel;

  SrcList *pTabList = pWInfo->pTabList;
  sqlite4 *db = pParse->db;

  /* Generate loop termination code.
  */
  sqlite4ExprCacheClear(pParse);
  for(i=pWInfo->nLevel-1; i>=0; i--){
    pLevel = &pWInfo->a[i];

    sqlite4VdbeResolveLabel(v, pLevel->addrCont);
    if( pLevel->op!=OP_Noop ){
      sqlite4VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
      sqlite4VdbeChangeP5(v, pLevel->p5);
    }
    if( pLevel->plan.wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite4VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        sqlite4VdbeJumpHere(v, pIn->addrInTop+1);
        sqlite4VdbeAddOp2(v, OP_Next, pIn->iCur, pIn->addrInTop);
        sqlite4VdbeJumpHere(v, pIn->addrInTop-1);
      }
      sqlite4DbFree(db, pLevel->u.in.aInLoop);
    }
    sqlite4VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqlite4VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
      assert( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
           || (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 );
      if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
      }
      if( pLevel->iIdxCur>=0 ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
      }
      if( pLevel->op==OP_Return ){
        sqlite4VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
      }else{
        sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
      }
................................................................................
  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite4VdbeResolveLabel(v, pWInfo->iBreak);

  /* Close all of the cursors that were opened by sqlite4WhereBegin.
  */
  assert( pWInfo->nLevel==1 || pWInfo->nLevel==pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
    SrcListItem *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );

    if( (pTab->tabFlags & TF_Ephemeral)==0
     && pTab->pSelect==0
     && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
    ){
      int ws = pLevel->plan.wsFlags;
      if( !pWInfo->okOnePass && (ws & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
      }
      if( (ws & WHERE_INDEXED)!=0 && (ws & WHERE_TEMP_INDEX)==0 ){
        if( pLevel->iIdxCur!=pTabItem->iCursor ){
          sqlite4VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
        }
      }
    }

    /* If this scan uses an index, make code substitutions to read data
    ** from the index in preference to the table. Sometimes, this means
    ** the table need never be read from. This is a performance boost,
    ** as the vdbe level waits until the table is read before actually
    ** seeking the table cursor to the record corresponding to the current
    ** position in the index.
    ** 
    ** Calls to the code generator in between sqlite4WhereBegin and
    ** sqlite4WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( (pLevel->plan.wsFlags & WHERE_TEMP_INDEX) && !db->mallocFailed ){

      VdbeOp *pOp;
      VdbeOp *pEnd;


      assert( pLevel->plan.u.pIdx );
      assert( pLevel->iTabCur!=pLevel->iIdxCur );
      pOp = sqlite4VdbeGetOp(v, pWInfo->iTop);
      pEnd = &pOp[sqlite4VdbeCurrentAddr(v) - pWInfo->iTop];

      while( pOp<pEnd ){


        if( pOp->p1==pLevel->iTabCur && pOp->opcode==OP_Column ){



          pOp->p1 = pLevel->iIdxCur;

        }
        pOp++;
      }
    }

    if( (pLevel->plan.wsFlags & WHERE_INDEXED)
     && (pLevel->plan.u.pIdx->eIndexType==SQLITE4_INDEX_FTS5)
    ){
      VdbeOp *pOp;
      VdbeOp *pEnd;

      assert( pLevel->iTabCur!=pLevel->iIdxCur );
      pOp = sqlite4VdbeGetOp(v, pWInfo->iTop);
      pEnd = &pOp[sqlite4VdbeCurrentAddr(v) - pWInfo->iTop];

      while( pOp<pEnd ){
        if( pOp->p1==pLevel->iTabCur && pOp->opcode==OP_Mifunction ){
          pOp->p1 = pLevel->iIdxCur;

        }
        pOp++;
      }
    }
  }

  /* Final cleanup
  */
  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
  whereInfoFree(db, pWInfo);
  return;
}







<




|

|
>
>
|

|








>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







<






|
|







 







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>













|
<
<


<







 







|







 







|
|

|
|
|
|
>
>



>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>

<
>











>






<
|
|
|
<
<
<
<
<
<
<

|
|
|
|
<
<
<
>
|
|
|
|
<
<
>
>
>
>
|
<
|
|
>
>
>
>
>
>
>
>
|
>
>
>
>
>
|
>

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>




<
<
<
>

<
<
>




<
<







 







|







 







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







|







 







|







 







|
|










|

|










|







 







|


<
<
<
<
<
<
<
<
<







 







|







 







|
|
|
|








|
>
>
>
>
>
|
<
<
>
>
>
|
>
>







 









|
|
|
<

|
>
|
|
|
<
<
<
<
<
|
<
>

<
<
<
<
<
<
>
>
>
>
>
|
|
>
|
<
<
<
<
<
|
>
>
>
>
>
>
>
>
>
>
|
>
|
>
>
>
>
>
>
>
|
|
|
<
<
<
<
|
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
>
>
|
>
>
>
>
>
>
>
|
<
<
<
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|

>

>

|







<
<
<
<
<







 







>
|
>
>







 







|







 







|







 







|
>



<







 







|









|



<












|








|










|


|


|







 







|







|







 







|
|








|







 







|



|







 







<







 







>










|






|

>







 







|
|
|
>



|




>







 







>
>
>
>
>
>
>





|





|







 







|







 







|
|
|
|
>



|
|
|







 







>







 







|
|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







|




|
<
|









>
|
<
<
<

<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
|
<
<
>


|
|
|
|







 







|












>
>
>





|
|
|
|
|
|
>









<
|
|
|
<
|
<
|
<
<
<
<
<
<

>
>
>
>
>
>
>
>
|
|
|
<
<
<
|
>
>
>
|
|
>
>
>
|
<
<
<
<
<
<
<



<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
>
>

<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
>
>
>
>
|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
>
|
<
>
>
|
<
>
|
<
<
<
<
<

<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
>
>
>
>
>
|
<
<
<
<
<
<
<
<
<
<
>
>
>
>
|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
>
>
>
|
<
<
<
<
<
|
>

<
<
<
<
<
<
<
<
<
<
<
<
<

|
<
<
<
<

<
<
<
<
<
<
<
>
>
|








|







 







|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<






|




|

>




<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<











|



|





|


|

<

>
>

>

<
>
>





|

|
|
|


>




|


>
>
>
>
>
>

<
>
>




|
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|


|
|
<
>
|


<
<
>

|
|

|






|
>
>










|

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|


>
|
|


|
>
|
<
<
<
<
>
|
>
|

|
|


|










|

|











<
<




|
|
|
|










|
>



|
|










<







 







>

<
>
|
|
|



|
>
>









|







 







|
|







 







<







 







>


<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<













<
>





|

>
>



|
<


>

>
>
>
>
>
>
>
>
>
>
|
<
<
<
>
>
>
>
>
>
>
>
>
>
|
<
<
>
>
>
|
>
>
|
<
<
|
|
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







|
|
|
>
>



|
>

|





|
|
|
|
<

<
<
<
<
<
<





|
<
<
<
<
<
<
<
<
|
<
|
<
>
|
<
<
<
<


<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







|





|
|
<
<





<
<
<
|

|
<
>
|
|


<
>

<
>



|
|
|
|


|

>

<

>
|
<
<
|

>
|
|









|
>
>
|
>
>
|
>
>







 







|

|






<
<


<
<
<
|
<
<
>

<
<
<
>

<
<
>
|

|



|







 







|

|
|
|
|










|





<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







|
>
>







 







|
<
<
<
<
<
<
<
<
<
<
<
<
<
<

<

>

>
>
>
>
>
>
>
>


>
>
>
>
|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
|
<
<
|
<
>
>
>
>
|
<

|
>
|
<

<



|
|

|

>


<







 







|
<



|


<

>






<
|
>
>
>
>




|









|


|
|
<




|







 







|
|
<
<
|
|
>
>


<
|




<
<


<
|

>
>
|
<
>
|

|
<
>
|







 







<
|



<


>
>

>
>


<
|
>
|











|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
>
>
>
>
>
>
>



<

<
>


<
<
<
<
<
<
|






>








<
|
<




>


>




|


>
|
>



|

>


<
>
>
>
>







 







|
|
|
|
|
|
|
|
<
<
<
<
<
<
<
<
<
<
|
<
|
>
>

|
|



|
|
<
<
<
<



>
|
>
>
>
|
|
|
>
|
<
|
|
<
<
|
|
|
>
|
<
>
|
<
<
>
|










>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|







 







|
|







 







|













|
|









|
>
>
|
<
>


|
<
>





|
<

|
<
<

<





|
>






|
|
|
|







 







|







 







|
|
>











|
|







 







>







 







|
|
>

|
|
|








|







>
>
>
>
|



|
|







 







>
>










|

|











|




|











|









|










>
>
>
>
>
>
>
>
>


>
>
>
>
>
>
>
|
>
|
>
>




|


|






|
>

>



|
|

<
|
<
<
>









>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>






>
>
>
>
|
>










>
>
>
|










|













|













>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>













|










|


>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
>

<
<
<
<
>

<
<
>
>
>
>
>
>
>
>
>
|
|
|


>
>
>
>
>
>
>
>




>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
>
>
>
>
>
>
>
>
|
>
|
>
>
>
>
>
|
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
|
|
>
>
>
>
>
>
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
|
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







|







 







|
>

|
<
<
<
<
<
<
<
<
<



|

|
|
|
>

<





>

<
<
|
>
|
<

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







<

|
<
<
<
<








>
>

<


<
<
>
|
|
|
>
>
>
>





|

|
>








>
>
>
>
>
>
>
>
>












<
<
<
<
<





<
|
|
<
<
<
<
<




|
|






|
>
>
>
>
|




|
|
|

|
|
|
>
>
>
>
>
|
|
<
<
<
<
<
<
<
>
>
|
|
|
|
<
>
|
|
<
<
<
<
<
<
<
<
<
<
<
<
<
>
|
<
<
<
|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
|
<
<
<
<
<
<
>
>
>
>
>
|
<
<
<
<
>
>
>
>
>
>
>
>
>
>
|
<
<
<
|
<
<
<
<
<
<
<
<
<

|
<
<
>
>
>
>
>
|
|
<
>
>
|
<
<
<
<
<
>
>
|
<
<
>
>
>
>
>
>
|
>
>
>
>
|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
>
>
>
|
>
>
|


<
<
<
<
<
<
<
<
>
>
>

<
<
<
|
<
<
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
<
<
<
<
>
>
|
<
<
<
<
>
>
>
>
>
>
>
|
|
<
<
<
<
<
>
>
>
|
<
<
<
<
<
<
<
<
<
|
|
<
|
<
<
<
<
<
<
<
<
<
<
>







|
>

|





<

<
|


>



<
<

>




|



>
>


|



|
|
>
>
>
>
>
>
>
>
|
>
>
>
>
>
>
>

<
>
|


|
|


>
|

>
|

|
|





|









|
|
|
|



|
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







>








>





|





|








|
|
|


|







 







|

|


>




|



|






|
|
|
|
<
<







|
>

<
>

<
<

|
<
<
>
>
|
>
>
>
|
>
|
<
|
<
<
|
|
<
<
<
<
<
<
<
<
<
<

>

<










17
18
19
20
21
22
23

24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
...
232
233
234
235
236
237
238

239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
...
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301


302
303

304
305
306
307
308
309
310
...
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
...
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410

411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429

430
431
432







433
434
435
436
437



438
439
440
441
442


443
444
445
446
447

448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518



519
520


521
522
523
524
525


526
527
528
529
530
531
532
...
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
...
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
...
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
...
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
...
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
...
692
693
694
695
696
697
698
699
700
701









702
703
704
705
706
707
708
...
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
...
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799


800
801
802
803
804
805
806
807
808
809
810
811
812
...
833
834
835
836
837
838
839
840
841
842
843
844

845
846
847
848
849
850





851

852
853






854
855
856
857
858
859
860
861
862





863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886




887
888

889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933

934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013

1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024



1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078





1079
1080
1081
1082
1083
1084
1085
....
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
....
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
....
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
....
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314

1315
1316
1317
1318
1319
1320
1321
....
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346

1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
....
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
....
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
....
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
....
1531
1532
1533
1534
1535
1536
1537

1538
1539
1540
1541
1542
1543
1544
....
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
....
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
....
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
....
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
....
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
....
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
....
1849
1850
1851
1852
1853
1854
1855
1856
1857






















1858
1859
1860
1861
1862
1863
1864
....
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878

1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890



1891























































1892


1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
....
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954

1955
1956
1957

1958

1959






1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971



1972
1973
1974
1975
1976
1977
1978
1979
1980
1981







1982
1983
1984

















1985
1986
1987



















1988
1989
1990
1991
1992















































1993
1994

1995
1996
1997

1998
1999





2000
















2001
2002
2003
2004
2005
2006










2007
2008
2009
2010
2011














2012
2013
2014
2015





2016
2017
2018













2019
2020




2021







2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
....
2064
2065
2066
2067
2068
2069
2070
2071








































































































2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089














































































2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115

2116
2117
2118
2119
2120
2121

2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150

2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184

2185
2186
2187
2188


2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244




2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278


2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313

2314
2315
2316
2317
2318
2319
2320
....
2326
2327
2328
2329
2330
2331
2332
2333
2334

2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
....
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
....
2378
2379
2380
2381
2382
2383
2384

2385
2386
2387
2388
2389
2390
2391
....
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412



























































































































































2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425

2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439

2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454



2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465


2466
2467
2468
2469
2470
2471
2472


2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
....
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595

2596






2597
2598
2599
2600
2601
2602








2603

2604

2605
2606




2607
2608














2609
2610
2611
2612
2613
2614
2615
....
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661


2662
2663
2664
2665
2666



2667
2668
2669

2670
2671
2672
2673
2674

2675
2676

2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690

2691
2692
2693


2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
....
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750


2751
2752



2753


2754
2755



2756
2757


2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
....
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812





















































































































































































































































































































































































































































































































































































2813
2814
2815
2816
2817
2818
2819
....
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
....
2918
2919
2920
2921
2922
2923
2924
2925














2926

2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944




















2945


2946

2947
2948
2949
2950
2951

2952
2953
2954
2955

2956

2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967

2968
2969
2970
2971
2972
2973
2974
....
3011
3012
3013
3014
3015
3016
3017
3018

3019
3020
3021
3022
3023
3024

3025
3026
3027
3028
3029
3030
3031
3032

3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056

3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
....
3122
3123
3124
3125
3126
3127
3128
3129
3130


3131
3132
3133
3134
3135
3136

3137
3138
3139
3140
3141


3142
3143

3144
3145
3146
3147
3148

3149
3150
3151
3152

3153
3154
3155
3156
3157
3158
3159
3160
3161
....
3168
3169
3170
3171
3172
3173
3174

3175
3176
3177
3178

3179
3180
3181
3182
3183
3184
3185
3186
3187

3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227

3228

3229
3230
3231






3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247

3248

3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274

3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
....
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310










3311

3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322




3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335

3336
3337


3338
3339
3340
3341
3342

3343
3344


3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
....
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
....
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562

3563
3564
3565
3566

3567
3568
3569
3570
3571
3572
3573

3574
3575


3576

3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
....
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
....
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
....
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
....
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
....
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889

3890


3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143




4144
4145


4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552

4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720

4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130

5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170


5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499

5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
....
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
....
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696









5697
5698
5699
5700
5701
5702
5703
5704
5705
5706

5707
5708
5709
5710
5711
5712
5713


5714
5715
5716

5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
....
5750
5751
5752
5753
5754
5755
5756

5757
5758




5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769

5770
5771


5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817





5818
5819
5820
5821
5822

5823
5824





5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860







5861
5862
5863
5864
5865
5866

5867
5868
5869













5870
5871



5872




















































5873






5874
5875
5876
5877
5878
5879




5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890



5891









5892
5893


5894
5895
5896
5897
5898
5899
5900

5901
5902
5903





5904
5905
5906


5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918



































5919
5920
5921
5922
5923
5924
5925
5926
5927








5928
5929
5930
5931



5932


5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946





5947
5948
5949




5950
5951
5952
5953
5954
5955
5956
5957
5958





5959
5960
5961
5962









5963
5964

5965










5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982

5983

5984
5985
5986
5987
5988
5989
5990


5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027

6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066














































6067
6068
6069
6070
6071
6072
6073
....
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
....
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165


6166
6167
6168
6169
6170
6171
6172
6173
6174
6175

6176
6177


6178
6179


6180
6181
6182
6183
6184
6185
6186
6187
6188

6189


6190
6191










6192
6193
6194

6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
** indices, you might also think of this module as the "query optimizer".
*/
#include "sqliteInt.h"

/* For VdbeCodecEncodeKey() - revisit this */
#include "vdbeInt.h"


/*
** Trace output macros
*/
#if defined(SQLITE4_TEST) || defined(SQLITE4_DEBUG)
/***/ int sqlite4WhereTrace = 0;
#endif
#if defined(SQLITE4_DEBUG) \
    && (defined(SQLITE4_TEST) || defined(SQLITE4_ENABLE_WHERETRACE))
# define WHERETRACE(K,X)  if(sqlite4WhereTrace&(K)) sqlite4DebugPrintf X
# define WHERETRACE_ENABLED 1
#else
# define WHERETRACE(K,X)
#endif

/* Forward reference
*/
typedef struct WhereClause WhereClause;
typedef struct WhereMaskSet WhereMaskSet;
typedef struct WhereOrInfo WhereOrInfo;
typedef struct WhereAndInfo WhereAndInfo;
typedef struct WhereLevel WhereLevel;
typedef struct WhereLoop WhereLoop;
typedef struct WherePath WherePath;
typedef struct WhereTerm WhereTerm;
typedef struct WhereLoopBuilder WhereLoopBuilder;
typedef struct WhereScan WhereScan;

/*
** Cost X is tracked as 10*log2(X) stored in a 16-bit integer.  The
** maximum cost for ordinary tables is 64*(2**63) which becomes 6900.
** (Virtual tables can return a larger cost, but let's assume they do not.)
** So all costs can be stored in a 16-bit unsigned integer without risk
** of overflow.
**
** Costs are estimates, so don't go to the computational trouble to compute
** 10*log2(X) exactly.  Instead, a close estimate is used.  Any value of
** X<=1 is stored as 0.  X=2 is 10.  X=3 is 16.  X=1000 is 99. etc.
**
** The tool/wherecosttest.c source file implements a command-line program
** that will convert between WhereCost to integers and do addition and
** multiplication on WhereCost values.  That command-line program is a
** useful utility to have around when working with this module.
*/
typedef unsigned short int WhereCost;

/*
** This object contains information needed to implement a single nested
** loop in WHERE clause.
**
** Contrast this object with WhereLoop.  This object describes the
** implementation of the loop.  WhereLoop describes the algorithm.
** This object contains a pointer to the WhereLoop algorithm as one of
** its elements.
**
** The WhereInfo object contains a single instance of this object for
** each term in the FROM clause (which is to say, for each of the
** nested loops as implemented).  The order of WhereLevel objects determines
** the loop nested order, with WhereInfo.a[0] being the outer loop and
** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop.
*/
struct WhereLevel {
  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
  int iTabCur;          /* The VDBE cursor used to access the table */
  int iIdxCur;          /* The VDBE cursor used to access pIdx */
  int addrBrk;          /* Jump here to break out of the loop */
  int addrNxt;          /* Jump here to start the next IN combination */
  int addrCont;         /* Jump here to continue with the next loop cycle */
  int addrFirst;        /* First instruction of interior of the loop */
  u8 iFrom;             /* Which entry in the FROM clause */
  u8 op, p5;            /* Opcode and P5 of the opcode that ends the loop */
  int p1, p2;           /* Operands of the opcode used to ends the loop */
  union {               /* Information that depends on pWLoop->wsFlags */
    struct {
      int nIn;              /* Number of entries in aInLoop[] */
      struct InLoop {
        int iCur;              /* The VDBE cursor used by this IN operator */
        int addrInTop;         /* Top of the IN loop */
        u8 eEndLoopOp;         /* IN Loop terminator. OP_Next or OP_Prev */
      } *aInLoop;           /* Information about each nested IN operator */
    } in;                 /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */
    Index *pCovidx;       /* Possible covering index for WHERE_MULTI_OR */
  } u;
  struct WhereLoop *pWLoop;  /* The selected WhereLoop object */
};

/*
** Each instance of this object represents an algorithm for evaluating one
** term of a join.  Every term of the FROM clause will have at least
** one corresponding WhereLoop object (unless INDEXED BY constraints
** prevent a query solution - which is an error) and many terms of the
** FROM clause will have multiple WhereLoop objects, each describing a
** potential way of implementing that FROM-clause term, together with
** dependencies and cost estimates for using the chosen algorithm.
**
** Query planning consists of building up a collection of these WhereLoop
** objects, then computing a particular sequence of WhereLoop objects, with
** one WhereLoop object per FROM clause term, that satisfy all dependencies
** and that minimize the overall cost.
*/
struct WhereLoop {
  Bitmask prereq;       /* Bitmask of other loops that must run first */
  Bitmask maskSelf;     /* Bitmask identifying table iTab */
#ifdef SQLITE4_DEBUG
  char cId;             /* Symbolic ID of this loop for debugging use */
#endif
  u8 iTab;              /* Position in FROM clause of table for this loop */
  u8 iSortIdx;          /* Sorting index number.  0==None */
  WhereCost rSetup;     /* One-time setup cost (ex: create transient index) */
  WhereCost rRun;       /* Cost of running each loop */
  WhereCost nOut;       /* Estimated number of output rows */
  union {
    struct {               /* Information for internal btree tables */
      int nEq;               /* Number of equality constraints */
      Index *pIndex;         /* Index used, or NULL */
    } btree;
    struct {               /* Information for virtual tables */
      int idxNum;            /* Index number */
      u8 needFree;           /* True if sqlite4_free(idxStr) is needed */
      u8 isOrdered;          /* True if satisfies ORDER BY */
      u16 omitMask;          /* Terms that may be omitted */
      char *idxStr;          /* Index identifier string */
    } vtab;
  } u;
  u32 wsFlags;          /* WHERE_* flags describing the plan */
  u16 nLTerm;           /* Number of entries in aLTerm[] */
  /**** whereLoopXfer() copies fields above ***********************/
# define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot)
  u16 nLSlot;           /* Number of slots allocated for aLTerm[] */
  WhereTerm **aLTerm;   /* WhereTerms used */
  WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */
  WhereTerm *aLTermSpace[4];  /* Initial aLTerm[] space */
};

/* Forward declaration of methods */
static int whereLoopResize(sqlite4*, WhereLoop*, int);

/*
** Each instance of this object holds a sequence of WhereLoop objects
** that implement some or all of a query plan.
**
** Think of each WhereLoop object as a node in a graph with arcs
** showing dependences and costs for travelling between nodes.  (That is
** not a completely accurate description because WhereLoop costs are a
** vector, not a scalar, and because dependences are many-to-one, not
** one-to-one as are graph nodes.  But it is a useful visualization aid.)
** Then a WherePath object is a path through the graph that visits some
** or all of the WhereLoop objects once.
**
** The "solver" works by creating the N best WherePath objects of length
** 1.  Then using those as a basis to compute the N best WherePath objects
** of length 2.  And so forth until the length of WherePaths equals the
** number of nodes in the FROM clause.  The best (lowest cost) WherePath
** at the end is the choosen query plan.
*/
struct WherePath {
  Bitmask maskLoop;     /* Bitmask of all WhereLoop objects in this path */
  Bitmask revLoop;      /* aLoop[]s that should be reversed for ORDER BY */
  WhereCost nRow;       /* Estimated number of rows generated by this path */
  WhereCost rCost;      /* Total cost of this path */
  u8 isOrdered;         /* True if this path satisfies ORDER BY */
  u8 isOrderedValid;    /* True if the isOrdered field is valid */
  WhereLoop **aLoop;    /* Array of WhereLoop objects implementing this path */
};

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by AND operators,
** usually, or sometimes subexpressions separated by OR.
**
................................................................................
** bits in the Bitmask.  So, in the example above, the cursor numbers
** would be mapped into integers 0 through 7.
**
** The number of terms in a join is limited by the number of bits
** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
** is only able to process joins with 64 or fewer tables.
*/

struct WhereTerm {
  Expr *pExpr;            /* Pointer to the subexpression that is this term */
  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
  union {
    int leftColumn;         /* Column number of X in "X <op> <expr>" */
    WhereOrInfo *pOrInfo;   /* Extra information if (eOperator & WO_OR)!=0 */
    WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */
  } u;
  u16 eOperator;          /* A WO_xx value describing <op> */
  u8 wtFlags;             /* TERM_xxx bit flags.  See below */
  u8 nChild;              /* Number of children that must disable us */
  WhereClause *pWC;       /* The clause this term is part of */
  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */
................................................................................
#define TERM_OR_OK      0x40   /* Used during OR-clause processing */
#ifdef SQLITE4_ENABLE_STAT3
#  define TERM_VNULL    0x80   /* Manufactured x>NULL or x<=NULL term */
#else
#  define TERM_VNULL    0x00   /* Disabled if not using stat3 */
#endif

/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
  WhereClause *pOrigWC;      /* Original, innermost WhereClause */
  WhereClause *pWC;          /* WhereClause currently being scanned */
  char *zCollName;           /* Required collating sequence, if not NULL */
  char idxaff;               /* Must match this affinity, if zCollName!=NULL */
  unsigned char nEquiv;      /* Number of entries in aEquiv[] */
  unsigned char iEquiv;      /* Next unused slot in aEquiv[] */
  u32 opMask;                /* Acceptable operators */
  int k;                     /* Resume scanning at this->pWC->a[this->k] */
  int aEquiv[22];            /* Cursor,Column pairs for equivalence classes */
};

/*
** An instance of the following structure holds all information about a
** WHERE clause.  Mostly this is a container for one or more WhereTerms.
**
** Explanation of pOuter:  For a WHERE clause of the form
**
**           a AND ((b AND c) OR (d AND e)) AND f
**
** There are separate WhereClause objects for the whole clause and for
** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
** subclauses points to the WhereClause object for the whole clause.
*/
struct WhereClause {
  WhereInfo *pWInfo;       /* WHERE clause processing context */


  WhereClause *pOuter;     /* Outer conjunction */
  u8 op;                   /* Split operator.  TK_AND or TK_OR */

  int nTerm;               /* Number of terms */
  int nSlot;               /* Number of entries in a[] */
  WhereTerm *a;            /* Each a[] describes a term of the WHERE cluase */
#if defined(SQLITE4_SMALL_STACK)
  WhereTerm aStatic[1];    /* Initial static space for a[] */
#else
  WhereTerm aStatic[8];    /* Initial static space for a[] */
................................................................................
};

/*
** An instance of the following structure keeps track of a mapping
** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
**
** The VDBE cursor numbers are small integers contained in 
** SrcListItem.iCursor and Expr.iTable fields.  For any given WHERE 
** clause, the cursor numbers might not begin with 0 and they might
** contain gaps in the numbering sequence.  But we want to make maximum
** use of the bits in our bitmasks.  This structure provides a mapping
** from the sparse cursor numbers into consecutive integers beginning
** with 0.
**
** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
................................................................................
*/
struct WhereMaskSet {
  int n;                        /* Number of assigned cursor values */
  int ix[BMS];                  /* Cursor assigned to each bit */
};

/*
** This object is a convenience wrapper holding all information needed
** to construct WhereLoop objects for a particular query.
*/
struct WhereLoopBuilder {
  WhereInfo *pWInfo;        /* Information about this WHERE */
  WhereClause *pWC;         /* WHERE clause terms */
  ExprList *pOrderBy;       /* ORDER BY clause */
  WhereLoop *pNew;          /* Template WhereLoop */
  WhereLoop *pBest;         /* If non-NULL, store single best loop here */
};

/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
**
** An instance of this object holds the complete state of the query
** planner.
*/
struct WhereInfo {
  Parse *pParse;            /* Parsing and code generating context */
  SrcList *pTabList;        /* List of tables in the join */
  ExprList *pOrderBy;       /* The ORDER BY clause or NULL */
  ExprList *pResultSet;     /* Result set. DISTINCT operates on these */
  WhereLoop *pLoops;        /* List of all WhereLoop objects */
  Bitmask revMask;          /* Mask of ORDER BY terms that need reversing */
  WhereCost nRowOut;        /* Estimated number of output rows */
  u16 wctrlFlags;           /* Flags originally passed to sqlite4WhereBegin() */
  u8 bOBSat;                /* ORDER BY satisfied by indices */
  u8 okOnePass;             /* Ok to use one-pass algorithm for UPDATE/DELETE */
  u8 untestedTerms;         /* Not all WHERE terms resolved by outer loop */
  u8 eDistinct;             /* One of the WHERE_DISTINCT_* values below */
  u8 nLevel;                /* Number of nested loop */
  int iTop;                 /* The very beginning of the WHERE loop */
  int iContinue;            /* Jump here to continue with next record */
  int iBreak;               /* Jump here to break out of the loop */
  int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
  WhereMaskSet sMaskSet;    /* Map cursor numbers to bitmasks */
  WhereClause sWC;          /* Decomposition of the WHERE clause */
  WhereLevel a[1];          /* Information about each nest loop in WHERE */
};

/*
** Bitmasks for the operators on WhereTerm objects.  These are all
** operators that are of interest to the query planner.  An
** OR-ed combination of these values can be used when searching for

** particular WhereTerms within a WhereClause.
*/
#define WO_IN     0x001
#define WO_EQ     0x002
#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
#define WO_MATCH  0x040
#define WO_ISNULL 0x080
#define WO_OR     0x100       /* Two or more OR-connected terms */
#define WO_AND    0x200       /* Two or more AND-connected terms */
#define WO_EQUIV  0x400       /* Of the form A==B, both columns */
#define WO_NOOP   0x800       /* This term does not restrict search space */

#define WO_ALL    0xfff       /* Mask of all possible WO_* values */
#define WO_SINGLE 0x0ff       /* Mask of all non-compound WO_* values */

/*

** These are definitions of bits in the WhereLoop.wsFlags field.
** The particular combination of bits in each WhereLoop help to
** determine the algorithm that WhereLoop represents.







*/
#define WHERE_COLUMN_EQ    0x00000001  /* x=EXPR */
#define WHERE_COLUMN_RANGE 0x00000002  /* x<EXPR and/or x>EXPR */
#define WHERE_COLUMN_IN    0x00000004  /* x IN (...) */
#define WHERE_COLUMN_NULL  0x00000008  /* x IS NULL */



#define WHERE_CONSTRAINT   0x0000000f  /* Any of the WHERE_COLUMN_xxx values */
#define WHERE_TOP_LIMIT    0x00000010  /* x<EXPR or x<=EXPR constraint */
#define WHERE_BTM_LIMIT    0x00000020  /* x>EXPR or x>=EXPR constraint */
#define WHERE_BOTH_LIMIT   0x00000030  /* Both x>EXPR and x<EXPR */
#define WHERE_IDX_ONLY     0x00000040  /* Use index only - omit table */


#define WHERE_IPK          0x00000100  /* x is the INTEGER PRIMARY KEY */
#define WHERE_INDEXED      0x00000200  /* WhereLoop.u.btree.pIndex is valid */
#define WHERE_VIRTUALTABLE 0x00000400  /* WhereLoop.u.vtab is valid */
#define WHERE_IN_ABLE      0x00000800  /* Able to support an IN operator */
#define WHERE_ONEROW       0x00001000  /* Selects no more than one row */

#define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
#define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */


/* Convert a WhereCost value (10 times log2(X)) into its integer value X.
** A rough approximation is used.  The value returned is not exact.
*/
static u64 whereCostToInt(WhereCost x){
  u64 n;
  if( x<10 ) return 1;
  n = x%10;
  x /= 10;
  if( n>=5 ) n -= 2;
  else if( n>=1 ) n -= 1;
  if( x>=3 ) return (n+8)<<(x-3);
  return (n+8)>>(3-x);
}

/*
** Return the estimated number of output rows from a WHERE clause
*/
u64 sqlite4WhereOutputRowCount(WhereInfo *pWInfo){
  return whereCostToInt(pWInfo->nRowOut);
}

/*
** Return one of the WHERE_DISTINCT_xxxxx values to indicate how this
** WHERE clause returns outputs for DISTINCT processing.
*/
int sqlite4WhereIsDistinct(WhereInfo *pWInfo){
  return pWInfo->eDistinct;
}

/*
** Return TRUE if the WHERE clause returns rows in ORDER BY order.
** Return FALSE if the output needs to be sorted.
*/
int sqlite4WhereIsOrdered(WhereInfo *pWInfo){
  return pWInfo->bOBSat!=0;
}

/*
** Return the VDBE address or label to jump to in order to continue
** immediately with the next row of a WHERE clause.
*/
int sqlite4WhereContinueLabel(WhereInfo *pWInfo){
  return pWInfo->iContinue;
}

/*
** Return the VDBE address or label to jump to in order to break
** out of a WHERE loop.
*/
int sqlite4WhereBreakLabel(WhereInfo *pWInfo){
  return pWInfo->iBreak;
}

/*
** Return TRUE if an UPDATE or DELETE statement can operate directly on
** the rowids returned by a WHERE clause.  Return FALSE if doing an
** UPDATE or DELETE might change subsequent WHERE clause results.
*/
int sqlite4WhereOkOnePass(WhereInfo *pWInfo){
  return pWInfo->okOnePass;
}

/*
** Initialize a preallocated WhereClause structure.
*/
static void whereClauseInit(
  WhereClause *pWC,        /* The WhereClause to be initialized */



  WhereInfo *pWInfo        /* The WHERE processing context */
){


  pWC->pWInfo = pWInfo;
  pWC->pOuter = 0;
  pWC->nTerm = 0;
  pWC->nSlot = ArraySize(pWC->aStatic);
  pWC->a = pWC->aStatic;


}

/* Forward reference */
static void whereClauseClear(WhereClause*);

/*
** Deallocate all memory associated with a WhereOrInfo object.
................................................................................
/*
** Deallocate a WhereClause structure.  The WhereClause structure
** itself is not freed.  This routine is the inverse of whereClauseInit().
*/
static void whereClauseClear(WhereClause *pWC){
  int i;
  WhereTerm *a;
  sqlite4 *db = pWC->pWInfo->pParse->db;
  for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
    if( a->wtFlags & TERM_DYNAMIC ){
      sqlite4ExprDelete(db, a->pExpr);
    }
    if( a->wtFlags & TERM_ORINFO ){
      whereOrInfoDelete(db, a->u.pOrInfo);
    }else if( a->wtFlags & TERM_ANDINFO ){
................................................................................
      whereAndInfoDelete(db, a->u.pAndInfo);
    }
  }
  if( pWC->a!=pWC->aStatic ){
    sqlite4DbFree(db, pWC->a);
  }
}


/*
** Skip over any TK_COLLATE and/or TK_AS operators at the root of
** an expression.
*/
Expr *sqlite4ExprSkipCollate(Expr *pExpr){
  while( pExpr && (pExpr->op==TK_COLLATE || pExpr->op==TK_AS) ){
    pExpr = pExpr->pLeft;
  }
  return pExpr;
}

/*
** A bit in a Bitmask
*/
#define MASKBIT(n)   (((Bitmask)1)<<(n))



/*
** Add a single new WhereTerm entry to the WhereClause object pWC.
** The new WhereTerm object is constructed from Expr p and with wtFlags.
** The index in pWC->a[] of the new WhereTerm is returned on success.
** 0 is returned if the new WhereTerm could not be added due to a memory
** allocation error.  The memory allocation failure will be recorded in
................................................................................
*/
static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
  WhereTerm *pTerm;
  int idx;
  testcase( wtFlags & TERM_VIRTUAL );  /* EV: R-00211-15100 */
  if( pWC->nTerm>=pWC->nSlot ){
    WhereTerm *pOld = pWC->a;
    sqlite4 *db = pWC->pWInfo->pParse->db;
    pWC->a = sqlite4DbMallocRaw(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
    if( pWC->a==0 ){
      if( wtFlags & TERM_DYNAMIC ){
        sqlite4ExprDelete(db, p);
      }
      pWC->a = pOld;
      return 0;
................................................................................
    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
    if( pOld!=pWC->aStatic ){
      sqlite4DbFree(db, pOld);
    }
    pWC->nSlot = sqlite4DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
  }
  pTerm = &pWC->a[idx = pWC->nTerm++];
  pTerm->pExpr = sqlite4ExprSkipCollate(p);
  pTerm->wtFlags = wtFlags;
  pTerm->pWC = pWC;
  pTerm->iParent = -1;
  return idx;
}

/*
................................................................................
** The original WHERE clause in pExpr is unaltered.  All this routine
** does is make slot[] entries point to substructure within pExpr.
**
** In the previous sentence and in the diagram, "slot[]" refers to
** the WhereClause.a[] array.  The slot[] array grows as needed to contain
** all terms of the WHERE clause.
*/
static void whereSplit(WhereClause *pWC, Expr *pExpr, u8 op){
  pWC->op = op;
  if( pExpr==0 ) return;
  if( pExpr->op!=op ){
    whereClauseInsert(pWC, pExpr, 0);
  }else{
    whereSplit(pWC, pExpr->pLeft, op);
    whereSplit(pWC, pExpr->pRight, op);
  }
}

/*
** Initialize a WhereMaskSet object
*/
#define initMaskSet(P)  (P)->n=0

/*
** Return the bitmask for the given cursor number.  Return 0 if
** iCursor is not in the set.
*/
static Bitmask getMask(WhereMaskSet *pMaskSet, int iCursor){
  int i;
  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
  for(i=0; i<pMaskSet->n; i++){
    if( pMaskSet->ix[i]==iCursor ){
      return MASKBIT(i);
    }
  }
  return 0;
}

/*
** Create a new mask for cursor iCursor.
................................................................................
*/
static void createMask(WhereMaskSet *pMaskSet, int iCursor){
  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
  pMaskSet->ix[pMaskSet->n++] = iCursor;
}

/*
** These routine walk (recursively) an expression tree and generates
** a bitmask indicating which tables are used in that expression
** tree.









*/
static Bitmask exprListTableUsage(WhereMaskSet*, ExprList*);
static Bitmask exprSelectTableUsage(WhereMaskSet*, Select*);
static Bitmask exprTableUsage(WhereMaskSet *pMaskSet, Expr *p){
  Bitmask mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
................................................................................
  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is
** allowed for an indexable WHERE clause term.  The allowed operators are
** "=", "<", ">", "<=", ">=", "IN", and "IS NULL"
**
** IMPLEMENTATION-OF: R-59926-26393 To be usable by an index a term must be
** of one of the following forms: column = expression column > expression
** column >= expression column < expression column <= expression
** expression = column expression > column expression >= column
** expression < column expression <= column column IN
** (expression-list) column IN (subquery) column IS NULL
................................................................................
*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**
** If left/right precedence rules come into play when determining the
** collating sequence, then COLLATE operators are adjusted to ensure
** that the collating sequence does not change.  For example:
** "Y collate NOCASE op X" becomes "X op Y" because any collation sequence on
** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_ExpCollate flag
** is not commuted.
*/
static void exprCommute(Parse *pParse, Expr *pExpr){
  u16 expRight = (pExpr->pRight->flags & EP_ExpCollate);
  u16 expLeft = (pExpr->pLeft->flags & EP_ExpCollate);
  assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
  if( expRight==expLeft ){
    /* Either X and Y both have COLLATE operator or neither do */
    if( expRight ){
      /* Both X and Y have COLLATE operators.  Make sure X is always
      ** used by clearing the EP_ExpCollate flag from Y. */
      pExpr->pRight->flags &= ~EP_ExpCollate;
    }else if( sqlite4ExprCollSeq(pParse, pExpr->pLeft)!=0 ){


      /* Neither X nor Y have COLLATE operators, but X has a non-default
      ** collating sequence.  So add the EP_ExpCollate marker on X to cause
      ** it to be searched first. */
      pExpr->pLeft->flags |= EP_ExpCollate;
    }
  }
  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
  if( pExpr->op>=TK_GT ){
    assert( TK_LT==TK_GT+2 );
    assert( TK_GE==TK_LE+2 );
    assert( TK_GT>TK_EQ );
    assert( TK_GT<TK_LE );
    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
................................................................................
  assert( op!=TK_EQ || c==WO_EQ );
  assert( op!=TK_LT || c==WO_LT );
  assert( op!=TK_LE || c==WO_LE );
  assert( op!=TK_GT || c==WO_GT );
  assert( op!=TK_GE || c==WO_GE );
  return c;
}

/*
** Advance to the next WhereTerm that matches according to the criteria
** established when the pScan object was initialized by whereScanInit().
** Return NULL if there are no more matching WhereTerms.

*/
static WhereTerm *whereScanNext(WhereScan *pScan){
  int iCur;            /* The cursor on the LHS of the term */
  int iColumn;         /* The column on the LHS of the term.  -1 for IPK */
  Expr *pX;            /* An expression being tested */
  WhereClause *pWC;    /* Shorthand for pScan->pWC */





  WhereTerm *pTerm;    /* The term being tested */

  int k = pScan->k;    /* Where to start scanning */







  while( pScan->iEquiv<=pScan->nEquiv ){
    iCur = pScan->aEquiv[pScan->iEquiv-2];
    iColumn = pScan->aEquiv[pScan->iEquiv-1];
    while( (pWC = pScan->pWC)!=0 ){
      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
        if( pTerm->leftCursor==iCur && pTerm->u.leftColumn==iColumn ){
          if( (pTerm->eOperator & WO_EQUIV)!=0
           && pScan->nEquiv<ArraySize(pScan->aEquiv)
          ){





            int j;
            pX = sqlite4ExprSkipCollate(pTerm->pExpr->pRight);
            assert( pX->op==TK_COLUMN );
            for(j=0; j<pScan->nEquiv; j+=2){
              if( pScan->aEquiv[j]==pX->iTable
               && pScan->aEquiv[j+1]==pX->iColumn ){
                  break;
              }
            }
            if( j==pScan->nEquiv ){
              pScan->aEquiv[j] = pX->iTable;
              pScan->aEquiv[j+1] = pX->iColumn;
              pScan->nEquiv += 2;
            }
          }
          if( (pTerm->eOperator & pScan->opMask)!=0 ){
            /* Verify the affinity and collating sequence match */
            if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){
              CollSeq *pColl;
              Parse *pParse = pWC->pWInfo->pParse;
              pX = pTerm->pExpr;
              if( !sqlite4IndexAffinityOk(pX, pScan->idxaff) ){
                continue;
              }




              assert(pX->pLeft);
              pColl = sqlite4BinaryCompareCollSeq(pParse,

                                                  pX->pLeft, pX->pRight);
              if( pColl==0 ) pColl = pParse->db->pDfltColl;
              if( sqlite4_stricmp(pColl->zName, pScan->zCollName) ){
                continue;
              }
            }
            if( (pTerm->eOperator & WO_EQ)!=0
             && (pX = pTerm->pExpr->pRight)->op==TK_COLUMN
             && pX->iTable==pScan->aEquiv[0]
             && pX->iColumn==pScan->aEquiv[1]
            ){
              continue;
            }
            pScan->k = k+1;
            return pTerm;
          }
        }
      }
      pScan->pWC = pScan->pWC->pOuter;
      k = 0;
    }
    pScan->pWC = pScan->pOrigWC;
    k = 0;
    pScan->iEquiv += 2;
  }
  return 0;
}

/*
** Return the table column number of the iIdxCol'th field in the index
** keys used by index pIdx, including any appended PRIMARY KEY fields.
** If there is no iIdxCol'th field in index pIdx, return -2.
**
** Example:
**
**   CREATE TABLE t1(a, b, c, PRIMARY KEY(a, b));
**   CREATE INDEX i1 ON t1(c);
**
** Index i1 in the example above consists of three fields - the indexed
** field "c" followed by the two primary key fields. The automatic PRIMARY
** KEY index consists of two fields only.
*/
static int idxColumnNumber(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = -2;
  if( iIdxCol<pIdx->nColumn ){

    iRet = pIdx->aiColumn[iIdxCol];
  }else if( pPk && iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    iRet = pPk->aiColumn[iIdxCol - pIdx->nColumn];
  }
  return iRet;
}

/*
** Return a pointer to a buffer containing the name of the collation 
** sequence used with the iIdxCol'th field in index pIdx, including any
** appended PRIMARY KEY fields.
*/
static char *idxColumnCollation(Index *pIdx, Index *pPk, int iIdxCol){
  char *zColl;
  assert( iIdxCol<(pIdx->nColumn + pPk->nColumn) );
  if( iIdxCol<pIdx->nColumn ){
    zColl = pIdx->azColl[iIdxCol];
  }else if( pPk && iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    zColl = pPk->azColl[iIdxCol - pIdx->nColumn];
  }
  return zColl;
}

/*
** Return the sort order (SQLITE4_SO_ASC or DESC) used by the iIdxCol'th 
** field in index pIdx, including any appended PRIMARY KEY fields.
*/
static int idxColumnSortOrder(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = SQLITE4_SO_ASC;
  if( iIdxCol<pIdx->nColumn ){
    iRet = pIdx->aSortOrder[iIdxCol];
  }
  return iRet;
}

/*
** Return the total number of fields in the index pIdx, including any
** trailing primary key fields.
*/
static int idxColumnCount(Index *pIdx, Index *pPk){
  return (pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn));
}

/*
** Initialize a WHERE clause scanner object.  Return a pointer to the
** first match.  Return NULL if there are no matches.
**
** The scanner will be searching the WHERE clause pWC.  It will look
** for terms of the form "X <op> <expr>" where X is column iColumn of table
** iCur.  The <op> must be one of the operators described by opMask.
**
** If the search is for X and the WHERE clause contains terms of the
** form X=Y then this routine might also return terms of the form
** "Y <op> <expr>".  The number of levels of transitivity is limited,
** but is enough to handle most commonly occurring SQL statements.
**
** If X is not the INTEGER PRIMARY KEY then X must be compatible with
** index pIdx.
*/
static WhereTerm *whereScanInit(
  WhereScan *pScan,       /* The WhereScan object being initialized */
  WhereClause *pWC,       /* The WHERE clause to be scanned */
  int iCur,               /* Cursor to scan for */
  int iColumn,            /* Column to scan for */
  u32 opMask,             /* Operator(s) to scan for */
  Index *pIdx             /* Must be compatible with this index */
){
  int j;

  /* memset(pScan, 0, sizeof(*pScan)); */
  pScan->pOrigWC = pWC;
  pScan->pWC = pWC;
  if( pIdx && iColumn>=0 ){
    Index *pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
    for(j=0; idxColumnNumber(pIdx, pPk, j)!=iColumn; j++){
      if( NEVER(j>=idxColumnCount(pIdx, pPk)) ) return 0;
    }
    pScan->zCollName = idxColumnCollation(pIdx, pPk, j);
  }else{

    pScan->idxaff = 0;
    pScan->zCollName = 0;
  }
  pScan->opMask = opMask;
  pScan->k = 0;
  pScan->aEquiv[0] = iCur;
  pScan->aEquiv[1] = iColumn;
  pScan->nEquiv = 2;
  pScan->iEquiv = 2;
  return whereScanNext(pScan);
}




/*
** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
** where X is a reference to the iColumn of table iCur and <op> is one of
** the WO_xx operator codes specified by the op parameter.
** Return a pointer to the term.  Return 0 if not found.
**
** The term returned might by Y=<expr> if there is another constraint in
** the WHERE clause that specifies that X=Y.  Any such constraints will be
** identified by the WO_EQUIV bit in the pTerm->eOperator field.  The
** aEquiv[] array holds X and all its equivalents, with each SQL variable
** taking up two slots in aEquiv[].  The first slot is for the cursor number
** and the second is for the column number.  There are 22 slots in aEquiv[]
** so that means we can look for X plus up to 10 other equivalent values.
** Hence a search for X will return <expr> if X=A1 and A1=A2 and A2=A3
** and ... and A9=A10 and A10=<expr>.
**
** If there are multiple terms in the WHERE clause of the form "X <op> <expr>"
** then try for the one with no dependencies on <expr> - in other words where
** <expr> is a constant expression of some kind.  Only return entries of
** the form "X <op> Y" where Y is a column in another table if no terms of
** the form "X <op> <const-expr>" exist.   If no terms with a constant RHS
** exist, try to return a term that does not use WO_EQUIV.
*/
static WhereTerm *findTerm(
  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
){
  WhereTerm *pResult = 0;
  WhereTerm *p;
  WhereScan scan;

  p = whereScanInit(&scan, pWC, iCur, iColumn, op, pIdx);
  while( p ){
    if( (p->prereqRight & notReady)==0 ){
      if( p->prereqRight==0 && (p->eOperator&WO_EQ)!=0 ){
        return p;
      }
      if( pResult==0 ) pResult = p;
    }
    p = whereScanNext(&scan);
  }
  return pResult;
}

/* Forward reference */
static void exprAnalyze(SrcList*, WhereClause*, int);

/*
** Call exprAnalyze on all terms in a WHERE clause.  





*/
static void exprAnalyzeAll(
  SrcList *pTabList,       /* the FROM clause */
  WhereClause *pWC         /* the WHERE clause to be analyzed */
){
  int i;
  for(i=pWC->nTerm-1; i>=0; i--){
................................................................................
    return 0;
  }
#ifdef SQLITE4_EBCDIC
  if( *pnoCase ) return 0;
#endif
  pList = pExpr->x.pList;
  pLeft = pList->a[1].pExpr;
  if( pLeft->op!=TK_COLUMN 
   || sqlite4ExprAffinity(pLeft)!=SQLITE4_AFF_TEXT 
   || IsVirtual(pLeft->pTab)
  ){
    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
    ** be the name of an indexed column with TEXT affinity. */
    return 0;
  }
  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */

  pRight = pList->a[0].pExpr;
................................................................................
    op = pRight->op2;
  }
  if( op==TK_VARIABLE ){
    Vdbe *pReprepare = pParse->pReprepare;
    int iCol = pRight->iColumn;
    pVal = sqlite4VdbeGetValue(pReprepare, iCol, SQLITE4_AFF_NONE);
    if( pVal && sqlite4_value_type(pVal)==SQLITE4_TEXT ){
      z = (char *)sqlite4_value_text(pVal, 0);
    }
    sqlite4VdbeSetVarmask(pParse->pVdbe, iCol);
    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
  }else if( op==TK_STRING ){
    z = pRight->u.zToken;
  }
  if( z ){
................................................................................
**     (B)     x=expr1 OR expr2=x OR x=expr3
**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C and
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression.  In other words, if the term
** being analyzed is:
**
**      x = expr1  OR  expr2 = x  OR  x = expr3
**
** then create a new virtual term like this:
................................................................................
** zero.  This term is not useful for search.
*/
static void exprAnalyzeOrTerm(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the complete WHERE clause */
  int idxTerm               /* Index of the OR-term to be analyzed */
){
  WhereInfo *pWInfo = pWC->pWInfo;        /* WHERE clause processing context */
  Parse *pParse = pWInfo->pParse;         /* Parser context */
  sqlite4 *db = pParse->db;               /* Database connection */
  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */

  int i;                                  /* Loop counters */
  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */

................................................................................
  */
  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
  assert( pExpr->op==TK_OR );
  pTerm->u.pOrInfo = pOrInfo = sqlite4DbMallocZero(db, sizeof(*pOrInfo));
  if( pOrInfo==0 ) return;
  pTerm->wtFlags |= TERM_ORINFO;
  pOrWc = &pOrInfo->wc;
  whereClauseInit(pOrWc, pWInfo);
  whereSplit(pOrWc, pExpr, TK_OR);
  exprAnalyzeAll(pSrc, pOrWc);
  if( db->mallocFailed ) return;
  assert( pOrWc->nTerm>=2 );

  /*
  ** Compute the set of tables that might satisfy cases 1 or 2.
  */
  indexable = ~(Bitmask)0;
  chngToIN = ~(Bitmask)0;
  for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
    if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
      WhereAndInfo *pAndInfo;

      assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
      chngToIN = 0;
      pAndInfo = sqlite4DbMallocRaw(db, sizeof(*pAndInfo));
      if( pAndInfo ){
        WhereClause *pAndWC;
        WhereTerm *pAndTerm;
        int j;
        Bitmask b = 0;
        pOrTerm->u.pAndInfo = pAndInfo;
        pOrTerm->wtFlags |= TERM_ANDINFO;
        pOrTerm->eOperator = WO_AND;
        pAndWC = &pAndInfo->wc;
        whereClauseInit(pAndWC, pWC->pWInfo);
        whereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
        exprAnalyzeAll(pSrc, pAndWC);
        pAndWC->pOuter = pWC;
        testcase( db->mallocFailed );
        if( !db->mallocFailed ){
          for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
            assert( pAndTerm->pExpr );
            if( allowedOp(pAndTerm->pExpr->op) ){
              b |= getMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
            }
          }
        }
        indexable &= b;
      }
    }else if( pOrTerm->wtFlags & TERM_COPIED ){
      /* Skip this term for now.  We revisit it when we process the
      ** corresponding TERM_VIRTUAL term */
    }else{
      Bitmask b;
      b = getMask(&pWInfo->sMaskSet, pOrTerm->leftCursor);
      if( pOrTerm->wtFlags & TERM_VIRTUAL ){
        WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
        b |= getMask(&pWInfo->sMaskSet, pOther->leftCursor);
      }
      indexable &= b;
      if( (pOrTerm->eOperator & WO_EQ)==0 ){
        chngToIN = 0;
      }else{
        chngToIN &= b;
      }
    }
  }

................................................................................
    ** will be recorded in iCursor and iColumn.  There might not be any
    ** such table and column.  Set okToChngToIN if an appropriate table
    ** and column is found but leave okToChngToIN false if not found.
    */
    for(j=0; j<2 && !okToChngToIN; j++){
      pOrTerm = pOrWc->a;
      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
        assert( pOrTerm->eOperator & WO_EQ );
        pOrTerm->wtFlags &= ~TERM_OR_OK;
        if( pOrTerm->leftCursor==iCursor ){
          /* This is the 2-bit case and we are on the second iteration and
          ** current term is from the first iteration.  So skip this term. */
          assert( j==1 );
          continue;
        }
        if( (chngToIN & getMask(&pWInfo->sMaskSet, pOrTerm->leftCursor))==0 ){
          /* This term must be of the form t1.a==t2.b where t2 is in the
          ** chngToIN set but t1 is not.  This term will be either preceeded
          ** or follwed by an inverted copy (t2.b==t1.a).  Skip this term 
          ** and use its inversion. */
          testcase( pOrTerm->wtFlags & TERM_COPIED );
          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
................................................................................
        iCursor = pOrTerm->leftCursor;
        break;
      }
      if( i<0 ){
        /* No candidate table+column was found.  This can only occur
        ** on the second iteration */
        assert( j==1 );
        assert( IsPowerOfTwo(chngToIN) );
        assert( chngToIN==getMask(&pWInfo->sMaskSet, iCursor) );
        break;
      }
      testcase( j==1 );

      /* We have found a candidate table and column.  Check to see if that
      ** table and column is common to every term in the OR clause */
      okToChngToIN = 1;
      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
        assert( pOrTerm->eOperator & WO_EQ );
        if( pOrTerm->leftCursor!=iCursor ){
          pOrTerm->wtFlags &= ~TERM_OR_OK;
        }else if( pOrTerm->u.leftColumn!=iColumn ){
          okToChngToIN = 0;
        }else{
          int affLeft, affRight;
          /* If the right-hand side is also a column, then the affinities
................................................................................
      Expr *pDup;            /* A transient duplicate expression */
      ExprList *pList = 0;   /* The RHS of the IN operator */
      Expr *pLeft = 0;       /* The LHS of the IN operator */
      Expr *pNew;            /* The complete IN operator */

      for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
        if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
        assert( pOrTerm->eOperator & WO_EQ );
        assert( pOrTerm->leftCursor==iCursor );
        assert( pOrTerm->u.leftColumn==iColumn );
        pDup = sqlite4ExprDup(db, pOrTerm->pExpr->pRight, 0);
        pList = sqlite4ExprListAppend(pWInfo->pParse, pList, pDup);
        pLeft = pOrTerm->pExpr->pLeft;
      }
      assert( pLeft!=0 );
      pDup = sqlite4ExprDup(db, pLeft, 0);
      pNew = sqlite4PExpr(pParse, TK_IN, pDup, 0, 0);
      if( pNew ){
        int idxNew;
................................................................................
      }
      pTerm->eOperator = WO_NOOP;  /* case 1 trumps case 2 */
    }
  }
}
#endif /* !SQLITE4_OMIT_OR_OPTIMIZATION && !SQLITE4_OMIT_SUBQUERY */


/*
** The input to this routine is an WhereTerm structure with only the
** "pExpr" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the WhereTerm
** structure.
**
** If the expression is of the form "<expr> <op> X" it gets commuted
................................................................................
** and the copy has idxParent set to the index of the original term.
*/
static void exprAnalyze(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the WHERE clause */
  int idxTerm               /* Index of the term to be analyzed */
){
  WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
  WhereTerm *pTerm;                /* The term to be analyzed */
  WhereMaskSet *pMaskSet;          /* Set of table index masks */
  Expr *pExpr;                     /* The expression to be analyzed */
  Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
  Bitmask prereqAll;               /* Prerequesites of pExpr */
  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
  int noCase = 0;                  /* LIKE/GLOB distinguishes case */
  int op;                          /* Top-level operator.  pExpr->op */
  Parse *pParse = pWInfo->pParse;  /* Parsing context */
  sqlite4 *db = pParse->db;        /* Database connection */

  if( db->mallocFailed ){
    return;
  }
  pTerm = &pWC->a[idxTerm];
  pMaskSet = &pWInfo->sMaskSet;
  pExpr = pTerm->pExpr;
  assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
    }else{
................................................................................
    extraRight = x-1;  /* ON clause terms may not be used with an index
                       ** on left table of a LEFT JOIN.  Ticket #3015 */
  }
  pTerm->prereqAll = prereqAll;
  pTerm->leftCursor = -1;
  pTerm->iParent = -1;
  pTerm->eOperator = 0;
  if( allowedOp(op) ){
    Expr *pLeft = sqlite4ExprSkipCollate(pExpr->pLeft);
    Expr *pRight = sqlite4ExprSkipCollate(pExpr->pRight);
    u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
    if( pLeft->op==TK_COLUMN ){
      pTerm->leftCursor = pLeft->iTable;
      pTerm->u.leftColumn = pLeft->iColumn;
      pTerm->eOperator = operatorMask(op) & opMask;
    }
    if( pRight && pRight->op==TK_COLUMN ){
      WhereTerm *pNew;
      Expr *pDup;
      u16 eExtraOp = 0;        /* Extra bits for pNew->eOperator */
      if( pTerm->leftCursor>=0 ){
        int idxNew;
        pDup = sqlite4ExprDup(db, pExpr, 0);
        if( db->mallocFailed ){
          sqlite4ExprDelete(db, pDup);
          return;
        }
................................................................................
        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
        if( idxNew==0 ) return;
        pNew = &pWC->a[idxNew];
        pNew->iParent = idxTerm;
        pTerm = &pWC->a[idxTerm];
        pTerm->nChild = 1;
        pTerm->wtFlags |= TERM_COPIED;
        if( pExpr->op==TK_EQ
         && !ExprHasProperty(pExpr, EP_FromJoin)
         && OptimizationEnabled(db, SQLITE4_Transitive)
        ){
          pTerm->eOperator |= WO_EQUIV;
          eExtraOp = WO_EQUIV;
        }
      }else{
        pDup = pExpr;
        pNew = pTerm;
      }
      exprCommute(pParse, pDup);
      pLeft = sqlite4ExprSkipCollate(pDup->pLeft);
      pNew->leftCursor = pLeft->iTable;
      pNew->u.leftColumn = pLeft->iColumn;
      testcase( (prereqLeft | extraRight) != prereqLeft );
      pNew->prereqRight = prereqLeft | extraRight;
      pNew->prereqAll = prereqAll;
      pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask;
    }
  }

#ifndef SQLITE4_OMIT_BETWEEN_OPTIMIZATION
  /* If a term is the BETWEEN operator, create two new virtual terms
  ** that define the range that the BETWEEN implements.  For example:
  **
................................................................................
  ){
    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
    Expr *pNewExpr1;
    Expr *pNewExpr2;
    int idxNew1;
    int idxNew2;
    Token sCollSeqName;  /* Name of collating sequence */

    pLeft = pExpr->x.pList->a[1].pExpr;
    pStr2 = sqlite4ExprDup(db, pStr1, 0);
    if( !db->mallocFailed ){
      u8 c, *pC;       /* Last character before the first wildcard */
      pC = (u8*)&pStr2->u.zToken[sqlite4Strlen30(pStr2->u.zToken)-1];
      c = *pC;
................................................................................
        if( c=='A'-1 ) isComplete = 0;   /* EV: R-64339-08207 */


        c = sqlite4UpperToLower[c];
      }
      *pC = c + 1;
    }
    sCollSeqName.z = noCase ? "NOCASE" : "BINARY";
    sCollSeqName.n = 6;
    pNewExpr1 = sqlite4ExprDup(db, pLeft, 0);
    sqlite4ExprSetCollByToken(pParse, pNewExpr1, &sCollSeqName);
    pNewExpr1 = sqlite4PExpr(pParse, TK_GE, pNewExpr1, pStr1, 0);
    idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew1==0 );
    exprAnalyze(pSrc, pWC, idxNew1);
    pNewExpr2 = sqlite4ExprDup(db, pLeft, 0);
    sqlite4ExprSetCollByToken(pParse, pNewExpr2, &sCollSeqName);
    pNewExpr2 = sqlite4PExpr(pParse, TK_LT, pNewExpr2, pStr2, 0);
    idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew2==0 );
    exprAnalyze(pSrc, pWC, idxNew2);
    pTerm = &pWC->a[idxTerm];
    if( isComplete ){
      pWC->a[idxNew1].iParent = idxTerm;
      pWC->a[idxNew2].iParent = idxTerm;
................................................................................
  ** TERM_VNULL tag will suppress the not-null check at the beginning
  ** of the loop.  Without the TERM_VNULL flag, the not-null check at
  ** the start of the loop will prevent any results from being returned.
  */
  if( pExpr->op==TK_NOTNULL
   && pExpr->pLeft->op==TK_COLUMN
   && pExpr->pLeft->iColumn>=0
   && OptimizationEnabled(db, SQLITE4_Stat3)
  ){
    Expr *pNewExpr;
    Expr *pLeft = pExpr->pLeft;
    int idxNew;
    WhereTerm *pNewTerm;

    pNewExpr = sqlite4PExpr(pParse, TK_GT,
................................................................................
  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
  ** an index for tables to the left of the join.
  */
  pTerm->prereqRight |= extraRight;
}

/*
** This function searches pList for a entry that matches the iCol-th column
** of index pIdx.






















**
** If such an expression is found, its index in pList->a[] is returned. If
** no expression is found, -1 is returned.
*/
static int findIndexCol(
  Parse *pParse,                  /* Parse context */
  ExprList *pList,                /* Expression list to search */
................................................................................
  Index *pIdx,                    /* Index to match column of */
  int iCol                        /* Column of index to match */
){
  int i;
  const char *zColl = pIdx->azColl[iCol];

  for(i=0; i<pList->nExpr; i++){
    Expr *p = sqlite4ExprSkipCollate(pList->a[i].pExpr);
    if( p->op==TK_COLUMN
     && p->iColumn==pIdx->aiColumn[iCol]
     && p->iTable==iBase
    ){
      CollSeq *pColl = sqlite4ExprCollSeq(pParse, pList->a[i].pExpr);

      if( ALWAYS(pColl) && 0==sqlite4_stricmp(pColl->zName, zColl) ){
        return i;
      }
    }
  }

  return -1;
}

/*
** Return true if the DISTINCT expression-list passed as the third argument
** is redundant.



**























































** A DISTINCT list is redundant if the database contains some subset of


** columns that are unique and non-null.
*/
static int isDistinctRedundant(
  Parse *pParse,            /* Parsing context */
  SrcList *pTabList,        /* The FROM clause */
  WhereClause *pWC,         /* The WHERE clause */
  ExprList *pDistinct       /* The result set that needs to be DISTINCT */
){
  Table *pTab;
  Index *pIdx;
  int i;                          
  int iBase;

  /* If there is more than one table or sub-select in the FROM clause of
................................................................................
  pTab = pTabList->a[0].pTab;

  /* If any of the expressions is an IPK column on table iBase, then return 
  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
  ** current SELECT is a correlated sub-query.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    Expr *p = sqlite4ExprSkipCollate(pDistinct->a[i].pExpr);
    if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
  }

  /* Loop through all indices on the table, checking each to see if it makes
  ** the DISTINCT qualifier redundant. It does so if:
  **
  **   1. The index is itself UNIQUE, and
  **
  **   2. All of the columns in the index are either part of the pDistinct
  **      list, or else the WHERE clause contains a term of the form "col=X",
  **      where X is a constant value. The collation sequences of the
  **      comparison and select-list expressions must match those of the index.
  **
  **   3. All of those index columns for which the WHERE clause does not
  **      contain a "col=X" term are subject to a NOT NULL constraint.
  */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    if( pIdx->onError==OE_None ) continue;
    for(i=0; i<pIdx->nColumn; i++){
      int iCol = pIdx->aiColumn[i];
      if( 0==findTerm(pWC, iBase, iCol, ~(Bitmask)0, WO_EQ, pIdx) ){
        int iIdxCol = findIndexCol(pParse, pDistinct, iBase, pIdx, i);
        if( iIdxCol<0 || pTab->aCol[pIdx->aiColumn[i]].notNull==0 ){
          break;
        }
      }
    }
    if( i==pIdx->nColumn ){
      /* This index implies that the DISTINCT qualifier is redundant. */
      return 1;
    }
  }

  return 0;
}


/* 
** The (an approximate) sum of two WhereCosts.  This computation is
** not a simple "+" operator because WhereCost is stored as a logarithmic

** value.

** 






*/
static WhereCost whereCostAdd(WhereCost a, WhereCost b){
  static const unsigned char x[] = {
     10, 10,                         /* 0,1 */
      9, 9,                          /* 2,3 */
      8, 8,                          /* 4,5 */
      7, 7, 7,                       /* 6,7,8 */
      6, 6, 6,                       /* 9,10,11 */
      5, 5, 5,                       /* 12-14 */
      4, 4, 4, 4,                    /* 15-18 */
      3, 3, 3, 3, 3, 3,              /* 19-24 */
      2, 2, 2, 2, 2, 2, 2,           /* 25-31 */



  };
  if( a>=b ){
    if( a>b+49 ) return a;
    if( a>b+31 ) return a+1;
    return a+x[a-b];
  }else{
    if( b>a+49 ) return b;
    if( b>a+31 ) return b+1;
    return b+x[b-a];
  }







}

/*

















** Convert an integer into a WhereCost.  In other words, compute a
** good approximatation for 10*log2(x).
*/



















static WhereCost whereCost(tRowcnt x){
  static WhereCost a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
  WhereCost y = 40;
  if( x<8 ){
    if( x<2 ) return 0;















































    while( x<8 ){  y -= 10; x <<= 1; }
  }else{

    while( x>255 ){ y += 40; x >>= 4; }
    while( x>15 ){  y += 10; x >>= 1; }
  }

  return a[x&7] + y - 10;
}






















#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Convert a double (as received from xBestIndex of a virtual table)
** into a WhereCost.  In other words, compute an approximation for
** 10*log2(x).
*/










static WhereCost whereCostFromDouble(double x){
  u64 a;
  WhereCost e;
  assert( sizeof(x)==8 && sizeof(a)==8 );
  if( x<=1 ) return 0;














  if( x<=2000000000 ) return whereCost((tRowcnt)x);
  memcpy(&a, &x, 8);
  e = (a>>52) - 1022;
  return e*10;





}
#endif /* SQLITE4_OMIT_VIRTUALTABLE */














/*
** Estimate the logarithm of the input value to base 2.




*/







static WhereCost estLog(WhereCost N){
  WhereCost x = whereCost(N);
  return x>33 ? x - 33 : 0;
}

/*
** Two routines for printing the content of an sqlite4_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE4_TEST or SQLITE4_DEBUG are defined, then these routines
** are no-ops.
*/
#if !defined(SQLITE4_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED)
static void TRACE_IDX_INPUTS(sqlite4_index_info *p){
  int i;
  if( !sqlite4WhereTrace ) return;
  for(i=0; i<p->nConstraint; i++){
    sqlite4DebugPrintf("  constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
       i,
       p->aConstraint[i].iColumn,
................................................................................
  sqlite4DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
}
#else
#define TRACE_IDX_INPUTS(A)
#define TRACE_IDX_OUTPUTS(A)
#endif

/*








































































































** Return TRUE if the WHERE clause term pTerm is of a form where it
** could be used with an index to access pSrc, assuming an appropriate
** index existed.
*/
static int termCanDriveIndex(
  WhereTerm *pTerm,              /* WHERE clause term to check */
  struct SrcListItem *pSrc,     /* Table we are trying to access */
  Bitmask notReady               /* Tables in outer loops of the join */
){
  char aff;
  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
  if( (pTerm->eOperator & WO_EQ)==0 ) return 0;
  if( (pTerm->prereqRight & notReady)!=0 ) return 0;
  if( pTerm->u.leftColumn<0 ) return 0;
  aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity;
  if( !sqlite4IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
  return 1;
}
















































































#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** Generate code to construct the Index object for an automatic index
** and to set up the WhereLevel object pLevel so that the code generator
** makes use of the automatic index.
*/
static void constructAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  struct SrcListItem *pSrc,  /* The FROM clause term to get the next index */
  Bitmask notReady,           /* Mask of cursors that are not available */
  WhereLevel *pLevel          /* Write new index here */
){
  int nColumn;                /* Number of columns in the constructed index */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  int nByte;                  /* Byte of memory needed for pIdx */
  Index *pIdx;                /* Object describing the transient index */
  Vdbe *v;                    /* Prepared statement under construction */
  int addrInit;               /* Address of the initialization bypass jump */
  Table *pTable;              /* The table being indexed */
  KeyInfo *pKeyinfo;          /* Key information for the index */   
  int addrTop;                /* Top of the index fill loop */
  int regRecord;              /* Register holding an index record */

  int n;                      /* Column counter */
  int i;                      /* Loop counter */
  int mxBitCol;               /* Maximum column in pSrc->colUsed */
  CollSeq *pColl;             /* Collating sequence to on a column */
  WhereLoop *pLoop;           /* The Loop object */
  Bitmask idxCols;            /* Bitmap of columns used for indexing */

  Bitmask extraCols;          /* Bitmap of additional columns */
  u8 sentWarning = 0;         /* True if a warnning has been issued */

  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  addrInit = sqlite4CodeOnce(pParse);

  /* Count the number of columns that will be added to the index
  ** and used to match WHERE clause constraints */
  nColumn = 0;
  pTable = pSrc->pTab;
  pWCEnd = &pWC->a[pWC->nTerm];
  pLoop = pLevel->pWLoop;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
      testcase( iCol==BMS );
      testcase( iCol==BMS-1 );
      if( !sentWarning ){
        sqlite4_log(SQLITE4_WARNING_AUTOINDEX,
            "automatic index on %s(%s)", pTable->zName,
            pTable->aCol[iCol].zName);
        sentWarning = 1;
      }
      if( (idxCols & cMask)==0 ){

        if( whereLoopResize(pParse->db, pLoop, nColumn+1) ) return;
        pLoop->aLTerm[nColumn++] = pTerm;
        idxCols |= cMask;
      }
    }
  }
  assert( nColumn>0 );
  pLoop->u.btree.nEq = pLoop->nLTerm = nColumn;
  pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED
                     | WHERE_AUTO_INDEX;

  /* Count the number of additional columns needed to create a
  ** covering index.  A "covering index" is an index that contains all
  ** columns that are needed by the query.  With a covering index, the
  ** original table never needs to be accessed.  Automatic indices must
  ** be a covering index because the index will not be updated if the
  ** original table changes and the index and table cannot both be used
  ** if they go out of sync.
  */
  extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
  mxBitCol = (pTable->nCol >= BMS-1) ? BMS-1 : pTable->nCol;
  testcase( pTable->nCol==BMS-1 );
  testcase( pTable->nCol==BMS-2 );
  for(i=0; i<mxBitCol; i++){
    if( extraCols & MASKBIT(i) ) nColumn++;
  }
  if( pSrc->colUsed & MASKBIT(BMS-1) ){
    nColumn += pTable->nCol - BMS + 1;
  }
  pLoop->wsFlags |= WHERE_COLUMN_EQ | WHERE_IDX_ONLY;

  /* Construct the Index object to describe this index */
  nByte = sizeof(Index);
  nByte += nColumn*sizeof(int);     /* Index.aiColumn */

  nByte += nColumn*sizeof(char*);   /* Index.azColl */
  nByte += nColumn;                 /* Index.aSortOrder */
  pIdx = sqlite4DbMallocZero(pParse->db, nByte);
  if( pIdx==0 ) return;


  pLoop->u.btree.pIndex = pIdx;
  pIdx->azColl = (char**)&pIdx[1];
  pIdx->aiColumn = (int*)&pIdx->azColl[nColumn];
  pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nColumn];
  pIdx->zName = "auto-index";
  pIdx->nColumn = nColumn;
  pIdx->pTable = pTable;
  n = 0;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
      testcase( iCol==BMS-1 );
      testcase( iCol==BMS );
      if( (idxCols & cMask)==0 ){
        Expr *pX = pTerm->pExpr;
        idxCols |= cMask;
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
        pIdx->azColl[n] = ALWAYS(pColl) ? pColl->zName : "BINARY";
        n++;
      }
    }
  }
  assert( (u32)n==pLoop->u.btree.nEq );

  /* Add additional columns needed to make the automatic index into
  ** a covering index */
  for(i=0; i<mxBitCol; i++){
    if( extraCols & MASKBIT(i) ){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
      n++;
    }
  }
  if( pSrc->colUsed & MASKBIT(BMS-1) ){
    for(i=BMS-1; i<pTable->nCol; i++){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
      n++;
    }
  }
  assert( n==nColumn );

  /* Create the automatic index */
  pKeyinfo = sqlite4IndexKeyinfo(pParse, pIdx);
  assert( pLevel->iIdxCur>=0 );
  pLevel->iIdxCur = pParse->nTab++;
  sqlite4VdbeAddOp4(v, OP_OpenAutoindex, pLevel->iIdxCur, nColumn+1, 0,
                    (char*)pKeyinfo, P4_KEYINFO_HANDOFF);
  VdbeComment((v, "for %s", pTable->zName));

  /* Fill the automatic index with content */
  addrTop = sqlite4VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur);
  regRecord = sqlite4GetTempReg(pParse);




  sqlite4GenerateIndexKey(pParse, pIdx, pLevel->iTabCur, regRecord, 1);
  sqlite4VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
  sqlite4VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite4VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
  sqlite4VdbeChangeP5(v, SQLITE4_STMTSTATUS_AUTOINDEX);
  sqlite4VdbeJumpHere(v, addrTop);
  sqlite4ReleaseTempReg(pParse, regRecord);
  
  /* Jump here when skipping the initialization */
  sqlite4VdbeJumpHere(v, addrInit);
}
#endif /* SQLITE4_OMIT_AUTOMATIC_INDEX */

#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Allocate and populate an sqlite4_index_info structure. It is the 
** responsibility of the caller to eventually release the structure
** by passing the pointer returned by this function to sqlite4_free().
*/
static sqlite4_index_info *allocateIndexInfo(
  Parse *pParse,
  WhereClause *pWC,
  struct SrcListItem *pSrc,
  ExprList *pOrderBy
){
  int i, j;
  int nTerm;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_orderby *pIdxOrderBy;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int nOrderBy;
  sqlite4_index_info *pIdxInfo;



  /* Count the number of possible WHERE clause constraints referring
  ** to this virtual table */
  for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
    testcase( pTerm->eOperator & WO_IN );
    testcase( pTerm->eOperator & WO_ISNULL );
    if( pTerm->eOperator & (WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    nTerm++;
  }

  /* If the ORDER BY clause contains only columns in the current 
  ** virtual table then allocate space for the aOrderBy part of
  ** the sqlite4_index_info structure.
  */
  nOrderBy = 0;
  if( pOrderBy ){
    int n = pOrderBy->nExpr;
    for(i=0; i<n; i++){
      Expr *pExpr = pOrderBy->a[i].pExpr;
      if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
    }
    if( i==n){
      nOrderBy = n;
    }
  }

  /* Allocate the sqlite4_index_info structure
  */
  pIdxInfo = sqlite4DbMallocZero(pParse->db, sizeof(*pIdxInfo)
                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
                           + sizeof(*pIdxOrderBy)*nOrderBy );
  if( pIdxInfo==0 ){
    sqlite4ErrorMsg(pParse, "out of memory");

    return 0;
  }

  /* Initialize the structure.  The sqlite4_index_info structure contains
  ** many fields that are declared "const" to prevent xBestIndex from
  ** changing them.  We have to do some funky casting in order to
  ** initialize those fields.
................................................................................
  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
  *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
  *(struct sqlite4_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
  *(struct sqlite4_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
                                                                   pUsage;

  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    u8 op;
    if( pTerm->leftCursor != pSrc->iCursor ) continue;

    assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
    testcase( pTerm->eOperator & WO_IN );
    testcase( pTerm->eOperator & WO_ISNULL );
    if( pTerm->eOperator & (WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    pIdxCons[j].iColumn = pTerm->u.leftColumn;
    pIdxCons[j].iTermOffset = i;
    op = (u8)pTerm->eOperator & WO_ALL;
    if( op==WO_IN ) op = WO_EQ;
    pIdxCons[j].op = op;
    /* The direct assignment in the previous line is possible only because
    ** the WO_ and SQLITE4_INDEX_CONSTRAINT_ codes are identical.  The
    ** following asserts verify this fact. */
    assert( WO_EQ==SQLITE4_INDEX_CONSTRAINT_EQ );
    assert( WO_LT==SQLITE4_INDEX_CONSTRAINT_LT );
    assert( WO_LE==SQLITE4_INDEX_CONSTRAINT_LE );
    assert( WO_GT==SQLITE4_INDEX_CONSTRAINT_GT );
    assert( WO_GE==SQLITE4_INDEX_CONSTRAINT_GE );
    assert( WO_MATCH==SQLITE4_INDEX_CONSTRAINT_MATCH );
    assert( pTerm->eOperator & (WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
    j++;
  }
  for(i=0; i<nOrderBy; i++){
    Expr *pExpr = pOrderBy->a[i].pExpr;
    pIdxOrderBy[i].iColumn = pExpr->iColumn;
    pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
  }
................................................................................

  return pIdxInfo;
}

/*
** The table object reference passed as the second argument to this function
** must represent a virtual table. This function invokes the xBestIndex()
** method of the virtual table with the sqlite4_index_info object that
** comes in as the 3rd argument to this function.
**
** If an error occurs, pParse is populated with an error message and a
** non-zero value is returned. Otherwise, 0 is returned and the output
** part of the sqlite4_index_info structure is left populated.
**
** Whether or not an error is returned, it is the responsibility of the
** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
................................................................................
** that this is required.
*/
static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite4_index_info *p){
  sqlite4_vtab *pVtab = sqlite4GetVTable(pParse->db, pTab)->pVtab;
  int i;
  int rc;


  TRACE_IDX_INPUTS(p);
  rc = pVtab->pModule->xBestIndex(pVtab, p);
  TRACE_IDX_OUTPUTS(p);

  if( rc!=SQLITE4_OK ){
    if( rc==SQLITE4_NOMEM ){
      pParse->db->mallocFailed = 1;
................................................................................
      sqlite4ErrorMsg(pParse, 
          "table %s: xBestIndex returned an invalid plan", pTab->zName);
    }
  }

  return pParse->nErr;
}
#endif /* !defined(SQLITE4_OMIT_VIRTUALTABLE) */





























































































































































#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the location of a particular key among all keys in an
** index.  Store the results in aStat as follows:
**
**    aStat[0]      Est. number of rows less than pVal
**    aStat[1]      Est. number of rows equal to pVal
**
** Return SQLITE4_OK on success.
*/
static int whereKeyStats(
  Parse *pParse,              /* Database connection */
  Index *pIdx,                /* Index to consider domain of */

  sqlite4_value *pVal,        /* Value to consider */
  int roundUp,                /* Round up if true.  Round down if false */
  tRowcnt *aStat              /* OUT: stats written here */
){
  tRowcnt n;
  IndexSample *aSample;
  int i, eType;
  int isEq = 0;
  i64 v;
  double r, rS;

  assert( roundUp==0 || roundUp==1 );
  assert( pIdx->nSample>0 );
  if( pVal==0 ) return SQLITE4_ERROR;

  n = pIdx->aiRowEst[0];
  aSample = pIdx->aSample;
  eType = sqlite4_value_type(pVal);

  if( eType==SQLITE4_INTEGER ){
    v = sqlite4_value_int64(pVal);
    r = (i64)v;
    for(i=0; i<pIdx->nSample; i++){
      if( aSample[i].eType==SQLITE4_NULL ) continue;
      if( aSample[i].eType>=SQLITE4_TEXT ) break;
      if( aSample[i].eType==SQLITE4_INTEGER ){
        if( aSample[i].u.i>=v ){
          isEq = aSample[i].u.i==v;
          break;
        }



      }else{
        assert( aSample[i].eType==SQLITE4_FLOAT );
        if( aSample[i].u.r>=r ){
          isEq = aSample[i].u.r==r;
          break;
        }
      }
    }
  }else if( eType==SQLITE4_FLOAT ){
    r = sqlite4_value_double(pVal);
    for(i=0; i<pIdx->nSample; i++){


      if( aSample[i].eType==SQLITE4_NULL ) continue;
      if( aSample[i].eType>=SQLITE4_TEXT ) break;
      if( aSample[i].eType==SQLITE4_FLOAT ){
        rS = aSample[i].u.r;
      }else{
        rS = aSample[i].u.i;
      }


      if( rS>=r ){
        isEq = rS==r;
        break;
      }
    }
  }else if( eType==SQLITE4_NULL ){
    i = 0;
    if( aSample[0].eType==SQLITE4_NULL ) isEq = 1;
  }else{
    assert( eType==SQLITE4_TEXT || eType==SQLITE4_BLOB );
    for(i=0; i<pIdx->nSample; i++){
      if( aSample[i].eType==SQLITE4_TEXT || aSample[i].eType==SQLITE4_BLOB ){
        break;
      }
    }
    if( i<pIdx->nSample ){      
      sqlite4 *db = pParse->db;
      CollSeq *pColl;
      const u8 *z;
      if( eType==SQLITE4_BLOB ){
        z = (const u8 *)sqlite4_value_blob(pVal);
        pColl = db->pDfltColl;
        assert( pColl->enc==SQLITE4_UTF8 );
      }else{
        pColl = sqlite4GetCollSeq(pParse, SQLITE4_UTF8, 0, *pIdx->azColl);
        /* If the collating sequence was unavailable, we should have failed
        ** long ago and never reached this point.  But we'll check just to
        ** be doubly sure. */
        if( NEVER(pColl==0) ) return SQLITE4_ERROR;
        z = (const u8 *)sqlite4ValueText(pVal, pColl->enc);
        if( !z ){
          return SQLITE4_NOMEM;
        }
        assert( z && pColl && pColl->xCmp );
      }
      n = sqlite4ValueBytes(pVal, pColl->enc);
  
      for(; i<pIdx->nSample; i++){
        int c;
        int eSampletype = aSample[i].eType;
        if( eSampletype<eType ) continue;
        if( eSampletype!=eType ) break;
#ifndef SQLITE4_OMIT_UTF16
        if( pColl->enc!=SQLITE4_UTF8 ){
          int nSample;
          char *zSample = sqlite4Utf8to16(
              db, pColl->enc, aSample[i].u.z, aSample[i].nByte, &nSample
          );
          if( !zSample ){
            assert( db->mallocFailed );
            return SQLITE4_NOMEM;
          }
          c = pColl->xCmp(pColl->pUser, nSample, zSample, n, z);
          sqlite4DbFree(db, zSample);
        }else
#endif
        {
          c = pColl->xCmp(pColl->pUser, aSample[i].nByte, aSample[i].u.z, n, z);
        }
        if( c>=0 ){
          if( c==0 ) isEq = 1;
          break;
        }
      }
    }
  }

  /* At this point, aSample[i] is the first sample that is greater than
  ** or equal to pVal.  Or if i==pIdx->nSample, then all samples are less
  ** than pVal.  If aSample[i]==pVal, then isEq==1.
  */
................................................................................
    aStat[0] = iLower + iGap;
  }
  return SQLITE4_OK;
}
#endif /* SQLITE4_ENABLE_STAT3 */

/*
** If expression pExpr represents a literal value, set *pp to point to
** an sqlite4_value structure containing the same value, with affinity
** aff applied to it, before returning. It is the responsibility of the 
** caller to eventually release this structure by passing it to 
** sqlite4ValueFree().
**
** If the current parse is a recompile (sqlite4Reprepare()) and pExpr
** is an SQL variable that currently has a non-NULL value bound to it,
** create an sqlite4_value structure containing this value, again with
** affinity aff applied to it, instead.
**
** If neither of the above apply, set *pp to NULL.
**
** If an error occurs, return an error code. Otherwise, SQLITE4_OK.
*/
#ifdef SQLITE4_ENABLE_STAT3
static int valueFromExpr(
  Parse *pParse, 
  Expr *pExpr, 
  u8 aff, 
  sqlite4_value **pp

){






  if( pExpr->op==TK_VARIABLE
   || (pExpr->op==TK_REGISTER && pExpr->op2==TK_VARIABLE)
  ){
    int iVar = pExpr->iColumn;
    sqlite4VdbeSetVarmask(pParse->pVdbe, iVar);
    *pp = sqlite4VdbeGetValue(pParse->pReprepare, iVar, aff);








    return SQLITE4_OK;

  }

  return sqlite4ValueFromExpr(pParse->db, pExpr, SQLITE4_UTF8, aff, pp);
}




#endif















/*
** This function is used to estimate the number of rows that will be visited
** by scanning an index for a range of values. The range may have an upper
** bound, a lower bound, or both. The WHERE clause terms that set the upper
** and lower bounds are represented by pLower and pUpper respectively. For
** example, assuming that index p is on t1(a):
**
................................................................................
*/
static int whereRangeScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index containing the range-compared column; "x" */
  int nEq,             /* index into p->aCol[] of the range-compared column */
  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
  WhereCost *pRangeDiv /* OUT: Reduce search space by this divisor */
){
  int rc = SQLITE4_OK;

#ifdef SQLITE4_ENABLE_STAT3

  if( nEq==0 && p->nSample && OptimizationEnabled(pParse->db, SQLITE4_Stat3) ){
    sqlite4_value *pRangeVal;


    tRowcnt iLower = 0;
    tRowcnt iUpper = p->aiRowEst[0];
    tRowcnt a[2];
    u8 aff = p->pTable->aCol[p->aiColumn[0]].affinity;




    if( pLower ){
      Expr *pExpr = pLower->pExpr->pRight;
      rc = valueFromExpr(pParse, pExpr, aff, &pRangeVal);

      assert( (pLower->eOperator & (WO_GT|WO_GE))!=0 );
      if( rc==SQLITE4_OK
       && whereKeyStats(pParse, p, pRangeVal, 0, a)==SQLITE4_OK
      ){
        iLower = a[0];

        if( (pLower->eOperator & WO_GT)!=0 ) iLower += a[1];
      }

      sqlite4ValueFree(pRangeVal);
    }
    if( rc==SQLITE4_OK && pUpper ){
      Expr *pExpr = pUpper->pExpr->pRight;
      rc = valueFromExpr(pParse, pExpr, aff, &pRangeVal);
      assert( (pUpper->eOperator & (WO_LT|WO_LE))!=0 );
      if( rc==SQLITE4_OK
       && whereKeyStats(pParse, p, pRangeVal, 1, a)==SQLITE4_OK
      ){
        iUpper = a[0];
        if( (pUpper->eOperator & WO_LE)!=0 ) iUpper += a[1];
      }
      sqlite4ValueFree(pRangeVal);
    }

    if( rc==SQLITE4_OK ){
      WhereCost iBase = whereCost(p->aiRowEst[0]);
      if( iUpper>iLower ){


        iBase -= whereCost(iUpper - iLower);
      }
      *pRangeDiv = iBase;
      WHERETRACE(0x100, ("range scan regions: %u..%u  div=%d\n",
                         (u32)iLower, (u32)iUpper, *pRangeDiv));
      return SQLITE4_OK;
    }
  }
#else
  UNUSED_PARAMETER(pParse);
  UNUSED_PARAMETER(p);
  UNUSED_PARAMETER(nEq);
#endif
  assert( pLower || pUpper );
  *pRangeDiv = 0;
  /* TUNING:  Each inequality constraint reduces the search space 4-fold.
  ** A BETWEEN operator, therefore, reduces the search space 16-fold */
  if( pLower && (pLower->wtFlags & TERM_VNULL)==0 ){
    *pRangeDiv += 20;  assert( 20==whereCost(4) );
  }
  if( pUpper ){
    *pRangeDiv += 20;  assert( 20==whereCost(4) );
  }
  return rc;
}

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
** an equality constraint x=VALUE and where that VALUE occurs in
................................................................................
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereEqualScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
  tRowcnt *pnRow       /* Write the revised row estimate here */
){
  sqlite4_value *pRhs = 0;  /* VALUE on right-hand side of pTerm */
  u8 aff;                   /* Column affinity */
  int rc;                   /* Subfunction return code */
  tRowcnt a[2];             /* Statistics */

  assert( p->aSample!=0 );
  assert( p->nSample>0 );


  aff = p->pTable->aCol[p->aiColumn[0]].affinity;
  if( pExpr ){



    rc = valueFromExpr(pParse, pExpr, aff, &pRhs);


    if( rc ) goto whereEqualScanEst_cancel;
  }else{



    pRhs = sqlite4ValueNew(pParse->db);
  }


  if( pRhs==0 ) return SQLITE4_NOTFOUND;
  rc = whereKeyStats(pParse, p, pRhs, 0, a);
  if( rc==SQLITE4_OK ){
    WHERETRACE(0x100,("equality scan regions: %d\n", (int)a[1]));
    *pnRow = a[1];
  }
whereEqualScanEst_cancel:
  sqlite4ValueFree(pRhs);
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
................................................................................
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereInScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
  tRowcnt *pnRow       /* Write the revised row estimate here */
){
  int rc = SQLITE4_OK;     /* Subfunction return code */
  tRowcnt nEst;           /* Number of rows for a single term */
  tRowcnt nRowEst = 0;    /* New estimate of the number of rows */
  int i;                  /* Loop counter */

  assert( p->aSample!=0 );
  for(i=0; rc==SQLITE4_OK && i<pList->nExpr; i++){
    nEst = p->aiRowEst[0];
    rc = whereEqualScanEst(pParse, p, pList->a[i].pExpr, &nEst);
    nRowEst += nEst;
  }
  if( rc==SQLITE4_OK ){
    if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0];
    *pnRow = nRowEst;
    WHERETRACE(0x100,("IN row estimate: est=%g\n", nRowEst));
  }
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */






















































































































































































































































































































































































































































































































































































/*
** Disable a term in the WHERE clause.  Except, do not disable the term
** if it controls a LEFT OUTER JOIN and it did not originate in the ON
** or USING clause of that join.
**
** Consider the term t2.z='ok' in the following queries:
**
................................................................................
** For a constraint of the form X=expr, the expression is evaluated and its
** result is left on the stack.  For constraints of the form X IN (...)
** this routine sets up a loop that will iterate over all values of X.
*/
static int codeEqualityTerm(
  Parse *pParse,      /* The parsing context */
  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
  WhereLevel *pLevel, /* The level of the FROM clause we are working on */
  int iEq,            /* Index of the equality term within this level */
  int bRev,           /* True for reverse-order IN operations */
  int iTarget         /* Attempt to leave results in this register */
){
  Expr *pX = pTerm->pExpr;
  Vdbe *v = pParse->pVdbe;
  int iReg;                  /* Register holding results */

  assert( iTarget>0 );
................................................................................
  if( pX->op==TK_EQ ){
    iReg = sqlite4ExprCodeTarget(pParse, pX->pRight, iTarget);
  }else if( pX->op==TK_ISNULL ){
    iReg = iTarget;
    sqlite4VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE4_OMIT_SUBQUERY
  }else{
    int eType;














    int iTab;

    struct InLoop *pIn;
    WhereLoop *pLoop = pLevel->pWLoop;

    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
      && pLoop->u.btree.pIndex!=0
      && pLoop->u.btree.pIndex->aSortOrder[iEq]
    ){
      testcase( iEq==0 );
      testcase( bRev );
      bRev = !bRev;
    }
    assert( pX->op==TK_IN );
    iReg = iTarget;
    eType = sqlite4FindInIndex(pParse, pX, 0);
    if( eType==IN_INDEX_INDEX_DESC ){
      testcase( bRev );
      bRev = !bRev;
    }




















    iTab = pX->iTable;


    sqlite4VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);

    assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 );
    pLoop->wsFlags |= WHERE_IN_ABLE;
    if( pLevel->u.in.nIn==0 ){
      pLevel->addrNxt = sqlite4VdbeMakeLabel(v);
    }

    pLevel->u.in.nIn++;
    pLevel->u.in.aInLoop =
       sqlite4DbReallocOrFree(pParse->db, pLevel->u.in.aInLoop,
                              sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn);

    pIn = pLevel->u.in.aInLoop;

    if( pIn ){
      pIn += pLevel->u.in.nIn - 1;
      pIn->iCur = iTab;
      if( eType==IN_INDEX_ROWID ){
        pIn->addrInTop = sqlite4VdbeAddOp2(v, OP_Rowid, iTab, iReg);
      }else{
        pIn->addrInTop = sqlite4VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
      }
      pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
      sqlite4VdbeAddOp1(v, OP_IsNull, iReg);
    }else{

      pLevel->u.in.nIn = 0;
    }
#endif
  }
  disableTerm(pLevel, pTerm);
  return iReg;
}
................................................................................
** no conversion should be attempted before using a t2.b value as part of
** a key to search the index. Hence the first byte in the returned affinity
** string in this example would be set to SQLITE4_AFF_NONE.
*/
static int codeAllEqualityTerms(
  Parse *pParse,        /* Parsing context */
  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
  int bRev,             /* Reverse the order of IN operators */

  int nExtraReg,        /* Number of extra registers to allocate */
  char **pzAff          /* OUT: Set to point to affinity string */
){
  int nEq;                      /* The number of == or IN constraints to code */
  Vdbe *v = pParse->pVdbe;      /* The vm under construction */
  Index *pIdx;                  /* The index being used for this loop */

  WhereTerm *pTerm;             /* A single constraint term */
  WhereLoop *pLoop;             /* The WhereLoop object */
  int j;                        /* Loop counter */
  int regBase;                  /* Base register */
  int nReg;                     /* Number of registers to allocate */
  char *zAff;                   /* Affinity string to return */

  /* This module is only called on query plans that use an index. */

  pLoop = pLevel->pWLoop;
  assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 );
  nEq = pLoop->u.btree.nEq;
  pIdx = pLoop->u.btree.pIndex;
  assert( pIdx!=0 );

  /* Figure out how many memory cells we will need then allocate them.
  */
  regBase = pParse->nMem + 1;
  nReg = pLoop->u.btree.nEq + nExtraReg;
  pParse->nMem += nReg;

  zAff = sqlite4DbStrDup(pParse->db, sqlite4IndexAffinityStr(v, pIdx));
  if( !zAff ){
    pParse->db->mallocFailed = 1;
  }

  /* Evaluate the equality constraints
  */
  assert( idxColumnCount(pIdx, sqlite4FindPrimaryKey(pIdx->pTable, 0))>=nEq );
  for(j=0; j<nEq; j++){
    int r1;
    pTerm = pLoop->aLTerm[j];
    assert( pTerm!=0 );

    /* The following true for indices with redundant columns. 
    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    r1 = codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, regBase+j);
    if( r1!=regBase+j ){
      if( nReg==1 ){
        sqlite4ReleaseTempReg(pParse, regBase);
        regBase = r1;
      }else{
        sqlite4VdbeAddOp2(v, OP_SCopy, r1, regBase+j);
      }
................................................................................
**
**   "a=? AND b>?"
**
** The returned pointer points to memory obtained from sqlite4DbMalloc().
** It is the responsibility of the caller to free the buffer when it is
** no longer required.
*/
static char *explainIndexRange(sqlite4 *db, WhereLoop *pLoop, Table *pTab){
  Index *pIndex = pLoop->u.btree.pIndex;


  int nEq = pLoop->u.btree.nEq;
  int i, j;
  Column *aCol = pTab->aCol;
  int *aiColumn = pIndex->aiColumn;
  StrAccum txt;


  if( nEq==0 && (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){
    return 0;
  }
  sqlite4StrAccumInit(&txt, 0, 0, SQLITE4_MAX_LENGTH);
  txt.db = db;


  sqlite4StrAccumAppend(&txt, " (", 2);
  for(i=0; i<nEq; i++){

    explainAppendTerm(&txt, i, aCol[aiColumn[i]].zName, "=");
  }

  j = i;
  if( pLoop->wsFlags&WHERE_BTM_LIMIT ){

    char *z = (j==pIndex->nColumn ) ? "rowid" : aCol[aiColumn[j]].zName;
    explainAppendTerm(&txt, i++, z, ">");
  }
  if( pLoop->wsFlags&WHERE_TOP_LIMIT ){

    char *z = (j==pIndex->nColumn ) ? "rowid" : aCol[aiColumn[j]].zName;
    explainAppendTerm(&txt, i, z, "<");
  }
  sqlite4StrAccumAppend(&txt, ")", 1);
  return sqlite4StrAccumFinish(&txt);
}

/*
** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
................................................................................
  SrcList *pTabList,              /* Table list this loop refers to */
  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  int iLevel,                     /* Value for "level" column of output */
  int iFrom,                      /* Value for "from" column of output */
  u16 wctrlFlags                  /* Flags passed to sqlite4WhereBegin() */
){
  if( pParse->explain==2 ){

    struct SrcListItem *pItem = &pTabList->a[pLevel->iFrom];
    Vdbe *v = pParse->pVdbe;      /* VM being constructed */
    sqlite4 *db = pParse->db;     /* Database handle */
    char *zMsg;                   /* Text to add to EQP output */

    int iId = pParse->iSelectId;  /* Select id (left-most output column) */
    int isSearch;                 /* True for a SEARCH. False for SCAN. */
    WhereLoop *pLoop;             /* The controlling WhereLoop object */
    u32 flags;                    /* Flags that describe this loop */

    pLoop = pLevel->pWLoop;
    flags = pLoop->wsFlags;
    if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return;


    isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0
            || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0))
            || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));

    zMsg = sqlite4MPrintf(db, "%s", isSearch?"SEARCH":"SCAN");
    if( pItem->pSelect ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId);
    }else{
      zMsg = sqlite4MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName);
    }

    if( pItem->zAlias ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
    }
    if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0
     && ALWAYS(pLoop->u.btree.pIndex!=0)
    ){
      char *zWhere = explainIndexRange(db, pLoop, pItem->pTab);
      zMsg = sqlite4MAppendf(db, zMsg,
               ((flags & WHERE_AUTO_INDEX) ? 
                   "%s USING AUTOMATIC %sINDEX%.0s%s" :
                   "%s USING %sINDEX %s%s"), 
               zMsg, ((flags & WHERE_IDX_ONLY) ? "COVERING " : ""),
               pLoop->u.btree.pIndex->zName, zWhere);
      sqlite4DbFree(db, zWhere);
    }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s USING INTEGER PRIMARY KEY", zMsg);

      if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid=?)", zMsg);
      }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid>? AND rowid<?)", zMsg);
      }else if( flags&WHERE_BTM_LIMIT ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid>?)", zMsg);
      }else if( ALWAYS(flags&WHERE_TOP_LIMIT) ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid<?)", zMsg);
      }
    }
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){

      zMsg = sqlite4MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,

                  pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
    }
#endif






    zMsg = sqlite4MAppendf(db, zMsg, "%s", zMsg);
    sqlite4VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
  }
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE4_OMIT_EXPLAIN */


/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */

  Bitmask notReady     /* Which tables are currently available */

){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */
  int omitTable;       /* True if we use the index only */
  int bRev;            /* True if we need to scan in reverse order */
  WhereLevel *pLevel;  /* The where level to be coded */
  WhereLoop *pLoop;    /* The WhereLoop object being coded */
  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  Parse *pParse;                  /* Parsing context */
  Vdbe *v;                        /* The prepared stmt under constructions */
  struct SrcListItem *pTabItem;  /* FROM clause term being coded */
  int addrBrk;                    /* Jump here to break out of the loop */
  int addrCont;                   /* Jump here to continue with next cycle */
  int iRowidReg = 0;        /* Rowid is stored in this register, if not zero */
  int iReleaseReg = 0;      /* Temp register to free before returning */
  Bitmask newNotReady;      /* Return value */

  pParse = pWInfo->pParse;
  v = pParse->pVdbe;
  pWC = &pWInfo->sWC;
  pLevel = &pWInfo->a[iLevel];
  pLoop = pLevel->pWLoop;
  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;

  bRev = (pWInfo->revMask>>iLevel)&1;
  omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0 
           && (pWInfo->wctrlFlags & WHERE_FORCE_TABLE)==0;
  VdbeNoopComment((v, "Begin Join Loop %d", iLevel));

  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that
................................................................................
  */
  if( pLevel->iFrom>0 && (pTabItem[0].jointype & JT_LEFT)!=0 ){
    pLevel->iLeftJoin = ++pParse->nMem;
    sqlite4VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

#if 0
  /* Special case of a FROM clause subquery implemented as a co-routine */
  if( pTabItem->viaCoroutine ){
    int regYield = pTabItem->regReturn;
    sqlite4VdbeAddOp2(v, OP_Integer, pTabItem->addrFillSub-1, regYield);
    pLevel->p2 =  sqlite4VdbeAddOp1(v, OP_Yield, regYield);
    VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName));
    sqlite4VdbeAddOp2(v, OP_If, regYield+1, addrBrk);










    pLevel->op = OP_Goto;

  }else
#endif

#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    /* Case 1:  The table is a virtual-table.  Use the VFilter and VNext
    **          to access the data.
    */
    int iReg;   /* P3 Value for OP_VFilter */
    int addrNotFound;
    int nConstraint = pLoop->nLTerm;





    sqlite4ExprCachePush(pParse);
    iReg = sqlite4GetTempRange(pParse, nConstraint+2);
    addrNotFound = pLevel->addrBrk;
    for(j=0; j<nConstraint; j++){
      int iTarget = iReg+j+2;
      pTerm = pLoop->aLTerm[j];
      if( pTerm==0 ) continue;
      if( pTerm->eOperator & WO_IN ){
        codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget);
        addrNotFound = pLevel->addrNxt;
      }else{
        sqlite4ExprCode(pParse, pTerm->pExpr->pRight, iTarget);

      }
    }


    sqlite4VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg);
    sqlite4VdbeAddOp2(v, OP_Integer, nConstraint, iReg+1);
    sqlite4VdbeAddOp4(v, OP_VFilter, iCur, addrNotFound, iReg,
                      pLoop->u.vtab.idxStr,
                      pLoop->u.vtab.needFree ? P4_MPRINTF : P4_STATIC);

    pLoop->u.vtab.needFree = 0;
    for(j=0; j<nConstraint && j<16; j++){


      if( (pLoop->u.vtab.omitMask>>j)&1 ){
        disableTerm(pLevel, pLoop->aLTerm[j]);
      }
    }
    pLevel->op = OP_VNext;
    pLevel->p1 = iCur;
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite4ExprCachePop(pParse, 1);
  }else
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

  if( (pLoop->wsFlags & WHERE_IPK)!=0
   && (pLoop->wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_EQ))!=0
  ){
    assert( 0 );

    /* Case 2:  We can directly reference a single row using an
    **          equality comparison against the ROWID field.  Or
    **          we reference multiple rows using a "rowid IN (...)"
    **          construct.
    */
    assert( pLoop->u.btree.nEq==1 );
    iReleaseReg = sqlite4GetTempReg(pParse);
    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->pExpr!=0 );
    assert( omitTable==0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, 0, bRev, iReleaseReg);
    addrNxt = pLevel->addrNxt;
    sqlite4VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
    sqlite4VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, iRowidReg);
    sqlite4ExprCacheAffinityChange(pParse, iRowidReg, 1);
    sqlite4ExprCacheStore(pParse, iCur, -1, iRowidReg);
    VdbeComment((v, "pk"));
    pLevel->op = OP_Noop;
  }else if( (pLoop->wsFlags & WHERE_IPK)!=0
         && (pLoop->wsFlags & WHERE_COLUMN_RANGE)!=0
  ){
    /* Case 3:  We have an inequality comparison against the ROWID field.
    */
    int testOp = OP_Noop;
    int start;
    int memEndValue = 0;
    WhereTerm *pStart, *pEnd;

    assert( 0 );

    assert( omitTable==0 );
    j = 0;
    pStart = pEnd = 0;
    if( pLoop->wsFlags & WHERE_BTM_LIMIT ) pStart = pLoop->aLTerm[j++];
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
    assert( pStart!=0 || pEnd!=0 );
    if( bRev ){
      pTerm = pStart;
      pStart = pEnd;
      pEnd = pTerm;
    }
    if( pStart ){
      Expr *pX;             /* The expression that defines the start bound */
      int r1, rTemp;        /* Registers for holding the start boundary */

      /* The following constant maps TK_xx codes into corresponding 
      ** seek opcodes.  It depends on a particular ordering of TK_xx
      */
      const u8 aMoveOp[] = {
           /* TK_GT */  OP_SeekGt,
           /* TK_LE */  OP_SeekLe,
           /* TK_LT */  OP_SeekLt,
           /* TK_GE */  OP_SeekGe
      };
      assert( TK_LE==TK_GT+1 );      /* Make sure the ordering.. */
      assert( TK_LT==TK_GT+2 );      /*  ... of the TK_xx values... */
      assert( TK_GE==TK_GT+3 );      /*  ... is correcct. */

      assert( (pStart->wtFlags & TERM_VNULL)==0 );
      testcase( pStart->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      pX = pStart->pExpr;
      assert( pX!=0 );
      testcase( pStart->leftCursor!=iCur ); /* transitive constraints */
      r1 = sqlite4ExprCodeTemp(pParse, pX->pRight, &rTemp);
      sqlite4VdbeAddOp3(v, aMoveOp[pX->op-TK_GT], iCur, addrBrk, r1);
      VdbeComment((v, "pk"));
      sqlite4ExprCacheAffinityChange(pParse, r1, 1);
      sqlite4ReleaseTempReg(pParse, rTemp);
      disableTerm(pLevel, pStart);
    }else{
      sqlite4VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrBrk);
    }
    if( pEnd ){
      Expr *pX;
      pX = pEnd->pExpr;
      assert( pX!=0 );
      assert( (pEnd->wtFlags & TERM_VNULL)==0 );
      testcase( pEnd->leftCursor!=iCur ); /* Transitive constraints */
      testcase( pEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      memEndValue = ++pParse->nMem;
      sqlite4ExprCode(pParse, pX->pRight, memEndValue);
      if( pX->op==TK_LT || pX->op==TK_GT ){
        testOp = bRev ? OP_Le : OP_Ge;
      }else{
        testOp = bRev ? OP_Lt : OP_Gt;
      }
      disableTerm(pLevel, pEnd);
    }
    start = sqlite4VdbeCurrentAddr(v);
    pLevel->op = bRev ? OP_Prev : OP_Next;
    pLevel->p1 = iCur;
    pLevel->p2 = start;
    assert( pLevel->p5==0 );
    if( testOp!=OP_Noop ){
      iRowidReg = iReleaseReg = sqlite4GetTempReg(pParse);
      sqlite4VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
      sqlite4ExprCacheStore(pParse, iCur, -1, iRowidReg);
      sqlite4VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
      sqlite4VdbeChangeP5(v, SQLITE4_AFF_NUMERIC | SQLITE4_JUMPIFNULL);
    }
  }else if( pLoop->wsFlags & WHERE_INDEXED ){
    /* Case 4: A scan using an index.
    **
    **         The WHERE clause may contain zero or more equality 
    **         terms ("==" or "IN" operators) that refer to the N
    **         left-most columns of the index. It may also contain
    **         inequality constraints (>, <, >= or <=) on the indexed
    **         column that immediately follows the N equalities. Only 
    **         the right-most column can be an inequality - the rest must
................................................................................
      OP_Noop,             /* 0: (!end_constraints) */
      OP_IdxGE,            /* 1: (end_constraints && !endEq && !bRev) */
      OP_IdxLE,            /* 2: (end_constraints && !endEq &&  bRev) */
      OP_IdxGT,            /* 3: (end_constraints &&  endEq && !bRev) */
      OP_IdxLT             /* 4: (end_constraints &&  endEq &&  bRev) */
    };

    int nEq = pLoop->u.btree.nEq;  /* Number of == or IN terms */
    int isMinQuery = 0;            /* If this is an optimized SELECT min(x).. */
    int regBase;                 /* Base register holding constraint values */
    int r1;                      /* Temp register */
    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
    int startEq;                 /* True if range start uses ==, >= or <= */
    int endEq;                   /* True if range end uses ==, >= or <= */
    int start_constraints;       /* Start of range is constrained */
................................................................................
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff;               /* Affinity for end of range constraint */
    int regEndKey;               /* Register for end-key */
    int iIneq;                   /* The table column subject to inequality */
    Index *pPk;                  /* Primary key index on same table as pIdx */

    pIdx = pLoop->u.btree.pIndex;
    pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    iIneq = idxColumnNumber(pIdx, pPk, nEq);
    iIdxCur = pLevel->iIdxCur;
    assert( iCur==pLevel->iTabCur );

    /* If this loop satisfies a sort order (pOrderBy) request that 
    ** was passed to this function to implement a "SELECT min(x) ..." 
    ** query, then the caller will only allow the loop to run for
    ** a single iteration. This means that the first row returned
    ** should not have a NULL value stored in 'x'. If column 'x' is
    ** the first one after the nEq equality constraints in the index,
    ** this requires some special handling.
    */
    if( (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)!=0
     && (pWInfo->bOBSat!=0)
     && (pIdx->nColumn>nEq)
    ){
      /* assert( pOrderBy->nExpr==1 ); */
      /* assert( pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq] ); */
      isMinQuery = 1;
      nExtraReg = 1;
    }

    /* Find any inequality constraint terms for the start and end 
    ** of the range. 
    */
    j = nEq;
    if( pLoop->wsFlags & WHERE_BTM_LIMIT ){

      pRangeStart = pLoop->aLTerm[j++];
      nExtraReg = 1;
    }
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ){

      pRangeEnd = pLoop->aLTerm[j++];
      nExtraReg = 1;
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase.

    */
    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);


    assert( (regBase+nEq+nExtraReg-1)<=pParse->nMem );

    zEndAff = sqlite4DbStrDup(pParse->db, zStartAff);
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE4_SO_ASC))
     || (bRev && pIdx->nColumn==nEq)
    ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
    }

    testcase( pRangeStart && (pRangeStart->eOperator & WO_LE)!=0 );
    testcase( pRangeStart && (pRangeStart->eOperator & WO_GE)!=0 );
    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
    start_constraints = pRangeStart || nEq>0;

    /* Seek the index cursor to the start of the range. */
    nConstraint = nEq;
    if( pRangeStart ){
................................................................................
    testcase( op==OP_Rewind );
    testcase( op==OP_Last );
    testcase( op==OP_SeekGt );
    testcase( op==OP_SeekGe );
    testcase( op==OP_SeekLe );
    testcase( op==OP_SeekLt );
    sqlite4VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
    if( nEq<idxColumnCount(pIdx, pPk) ){
      sqlite4VdbeChangeP5(v, OPFLAG_PARTIALKEY);
    }

    /* Set variable op to the instruction required to determine if the
    ** cursor is passed the end of the range. If the range is unbounded,
    ** then set op to OP_Noop. Nothing to do in this case.  */
    assert( (endEq==0 || endEq==1) );
................................................................................
    testcase( op==OP_Noop );
    testcase( op==OP_IdxGE );
    testcase( op==OP_IdxLT );
    testcase( op==OP_IdxLE );
    testcase( op==OP_IdxGT );

    if( op!=OP_Noop ){
      /* Load the value for the inequality constraint at the end of the
      ** range (if any).
      */
      nConstraint = nEq;
      if( pRangeEnd ){
        Expr *pRight = pRangeEnd->pExpr->pRight;
        sqlite4ExprCacheRemove(pParse, regBase+nEq, 1);
        sqlite4ExprCode(pParse, pRight, regBase+nEq);
        if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
          sqlite4ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
        }
        if( zEndAff ){
          if( sqlite4CompareAffinity(pRight, zEndAff[nEq])==SQLITE4_AFF_NONE){
            /* Since the comparison is to be performed with no conversions
            ** applied to the operands, set the affinity to apply to pRight to 
            ** SQLITE4_AFF_NONE.  */
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
          if( sqlite4ExprNeedsNoAffinityChange(pRight, zEndAff[nEq]) ){
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
        }  
        codeApplyAffinity(pParse, regBase, nEq+1, zEndAff);
................................................................................
      }

      /* Now compute an end-key using OP_MakeIdxKey */
      regEndKey = ++pParse->nMem;
      sqlite4VdbeAddOp4Int(
          v, OP_MakeIdxKey, iIdxCur, regBase, regEndKey, nConstraint
      );

    }

    sqlite4DbFree(pParse->db, zStartAff);
    sqlite4DbFree(pParse->db, zEndAff);

    /* Top of the loop body */
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
................................................................................
    if( pIdx->eIndexType!=SQLITE4_INDEX_PRIMARYKEY
     && pIdx->eIndexType!=SQLITE4_INDEX_TEMP
    ){
      sqlite4VdbeAddOp3(v, OP_SeekPk, iCur, 0, iIdxCur);
    }

    /* If there are inequality constraints, check that the value
    ** of the table column that the inequality contrains is not NULL.
    ** If it is, jump to the next iteration of the loop.
    */
    r1 = sqlite4GetTempReg(pParse);
    testcase( pLoop->wsFlags & WHERE_BTM_LIMIT );
    testcase( pLoop->wsFlags & WHERE_TOP_LIMIT );
    if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 ){
      sqlite4ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iIneq, r1);
      sqlite4VdbeAddOp2(v, OP_IsNull, r1, addrCont);
    }
    sqlite4ReleaseTempReg(pParse, r1);

    /* Record the instruction used to terminate the loop. Disable 
    ** WHERE clause terms made redundant by the index range scan.
    */
    if( pLoop->wsFlags & WHERE_ONEROW ){
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;
    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
      pLevel->p5 = SQLITE4_STMTSTATUS_FULLSCAN_STEP;
    }else{
      assert( pLevel->p5==0 );
    }
  }else

#ifndef SQLITE4_OMIT_OR_OPTIMIZATION
  if( pLoop->wsFlags & WHERE_MULTI_OR ){
    /* Case 5:  Two or more separately indexed terms connected by OR
    **
    ** Example:
    **
    **   CREATE TABLE t1(a,b,c,d);
    **   CREATE INDEX i1 ON t1(a);
    **   CREATE INDEX i2 ON t1(b);
    **   CREATE INDEX i3 ON t1(c);
................................................................................
    **          Return     2                # Jump back to the Gosub
    **
    **       B: <after the loop>
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */
    Index *pCov = 0;             /* Potential covering index (or NULL) */
    int iCovCur = pParse->nTab++;  /* Cursor used for index scans (if any) */

    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regKeyset = 0;                        /* Register for RowSet object */
    int regKey = 0;                           /* Register holding key */
    int iLoopBody = sqlite4VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
   
    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->eOperator & WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList in pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite4WhereBegin().
    */
    if( pWInfo->nLevel>1 ){
      int nNotReady;                 /* The number of notReady tables */
      struct SrcListItem *origSrc;     /* Original list of tables */
      nNotReady = pWInfo->nLevel - iLevel - 1;
      pOrTab = sqlite4StackAllocRaw(pParse->db,
                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
      if( pOrTab==0 ) return notReady;
      pOrTab->nAlloc = (u8)(nNotReady + 1);
      pOrTab->nSrc = pOrTab->nAlloc;
      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
      origSrc = pWInfo->pTabList->a;
      for(k=1; k<=nNotReady; k++){
        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
      }
    }else{
      pOrTab = pWInfo->pTabList;
    }

    /* Initialize the keyset register to contain NULL. An SQL NULL is 
    ** equivalent to an empty keyset.
    **
    ** Also initialize regReturn to contain the address of the instruction 
    ** immediately following the OP_Return at the bottom of the loop. This
    ** is required in a few obscure LEFT JOIN cases where control jumps
    ** over the top of the loop into the body of it. In this case the 
    ** correct response for the end-of-loop code (the OP_Return) is to 
    ** fall through to the next instruction, just as an OP_Next does if
    ** called on an uninitialized cursor.
    */
    if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
      regKeyset = ++pParse->nMem;
      regKey = ++pParse->nMem;
      sqlite4VdbeAddOp2(v, OP_Null, 0, regKeyset);
    }
    iRetInit = sqlite4VdbeAddOp2(v, OP_Integer, 0, regReturn);

    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
    ** Then for every term xN, evaluate as the subexpression: xN AND z
    ** That way, terms in y that are factored into the disjunction will
    ** be picked up by the recursive calls to sqlite4WhereBegin() below.
    **
    ** Actually, each subexpression is converted to "xN AND w" where w is
    ** the "interesting" terms of z - terms that did not originate in the
    ** ON or USING clause of a LEFT JOIN, and terms that are usable as 
    ** indices.
    **
    ** This optimization also only applies if the (x1 OR x2 OR ...) term
    ** is not contained in the ON clause of a LEFT JOIN.
    ** See ticket http://www.sqlite.org/src/info/f2369304e4
    */
    if( pWC->nTerm>1 ){
      int iTerm;
      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
        Expr *pExpr = pWC->a[iTerm].pExpr;
        if( ExprHasProperty(pExpr, EP_FromJoin) ) continue;
        if( pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_ORINFO) ) continue;
        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
        pExpr = sqlite4ExprDup(pParse->db, pExpr, 0);
        pAndExpr = sqlite4ExprAnd(pParse->db, pAndExpr, pExpr);
      }
      if( pAndExpr ){
        pAndExpr = sqlite4PExpr(pParse, TK_AND, 0, pAndExpr, 0);
      }
    }

    for(ii=0; ii<pOrWc->nTerm; ii++){
      WhereTerm *pOrTerm = &pOrWc->a[ii];
      if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){
        WhereInfo *pSubWInfo;          /* Info for single OR-term scan */
        Expr *pOrExpr = pOrTerm->pExpr;
        if( pAndExpr && !ExprHasProperty(pOrExpr, EP_FromJoin) ){
          pAndExpr->pLeft = pOrExpr;
          pOrExpr = pAndExpr;
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
        assert( pSubWInfo || pParse->nErr || pParse->db->mallocFailed );
        if( pSubWInfo ){
          WhereLoop *pSubLoop;
          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);

            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, regKeyset,


                                 sqlite4VdbeCurrentAddr(v)+2, regKey, iSet);
          }
          sqlite4VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.
          */
          if( pSubWInfo->untestedTerms ) untestedTerms = 1;

          /* If all of the OR-connected terms are optimized using the same
          ** index, and the index is opened using the same cursor number
          ** by each call to sqlite4WhereBegin() made by this loop, it may
          ** be possible to use that index as a covering index.
          **
          ** If the call to sqlite4WhereBegin() above resulted in a scan that
          ** uses an index, and this is either the first OR-connected term
          ** processed or the index is the same as that used by all previous
          ** terms, set pCov to the candidate covering index. Otherwise, set 
          ** pCov to NULL to indicate that no candidate covering index will 
          ** be available.
          */
#if 0
          pSubLoop = pSubWInfo->a[0].pWLoop;
          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
          ){
            assert( pSubWInfo->a[0].iIdxCur==iCovCur );
            pCov = pSubLoop->u.btree.pIndex;
          }else{
            pCov = 0;
          }
#endif

          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite4WhereEnd(pSubWInfo);
        }
      }
    }
    pLevel->u.pCovidx = pCov;
    if( pCov ) pLevel->iIdxCur = iCovCur;
    if( pAndExpr ){
      pAndExpr->pLeft = 0;
      sqlite4ExprDelete(pParse->db, pAndExpr);
    }
    sqlite4VdbeChangeP1(v, iRetInit, sqlite4VdbeCurrentAddr(v));
    sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite4VdbeResolveLabel(v, iLoopBody);

    if( pWInfo->nLevel>1 ) sqlite4StackFree(pParse->db, pOrTab);
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */

  {
    /* TODO: This case is currently being used. Why can't it use the 
    ** index case instead? */ 

    /* Case 6:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );
    pLevel->op = aStep[bRev];
    pLevel->p1 = iCur;
    pLevel->p2 = 1 + sqlite4VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
    pLevel->p5 = SQLITE4_STMTSTATUS_FULLSCAN_STEP;
  }
  newNotReady = notReady & ~getMask(&pWInfo->sMaskSet, iCur);

  /* Insert code to test every subexpression that can be completely
  ** computed using the current set of tables.
  **
  ** IMPLEMENTATION-OF: R-49525-50935 Terms that cannot be satisfied through
  ** the use of indices become tests that are evaluated against each row of
  ** the relevant input tables.
  */
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
    testcase( pTerm->wtFlags & TERM_CODED );
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->prereqAll & newNotReady)!=0 ){
      testcase( pWInfo->untestedTerms==0
               && (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
      pWInfo->untestedTerms = 1;
      continue;
    }
    pE = pTerm->pExpr;
    assert( pE!=0 );
    if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
      continue;
    }
    sqlite4ExprIfFalse(pParse, pE, addrCont, SQLITE4_JUMPIFNULL);
    pTerm->wtFlags |= TERM_CODED;
  }

  /* Insert code to test for implied constraints based on transitivity
  ** of the "==" operator.
  **
  ** Example: If the WHERE clause contains "t1.a=t2.b" and "t2.b=123"
  ** and we are coding the t1 loop and the t2 loop has not yet coded,
  ** then we cannot use the "t1.a=t2.b" constraint, but we can code
  ** the implied "t1.a=123" constraint.
  */
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    WhereTerm *pAlt;
    Expr sEq;
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( pTerm->eOperator!=(WO_EQUIV|WO_EQ) ) continue;
    if( pTerm->leftCursor!=iCur ) continue;
    if( pLevel->iLeftJoin ) continue;
    pE = pTerm->pExpr;
    assert( !ExprHasProperty(pE, EP_FromJoin) );
    assert( (pTerm->prereqRight & newNotReady)!=0 );
    pAlt = findTerm(pWC, iCur, pTerm->u.leftColumn, notReady, WO_EQ|WO_IN, 0);
    if( pAlt==0 ) continue;
    if( pAlt->wtFlags & (TERM_CODED) ) continue;
    testcase( pAlt->eOperator & WO_EQ );
    testcase( pAlt->eOperator & WO_IN );
    VdbeNoopComment((v, "begin transitive constraint"));
    sEq = *pAlt->pExpr;
    sEq.pLeft = pE->pLeft;
    sqlite4ExprIfFalse(pParse, &sEq, addrCont, SQLITE4_JUMPIFNULL);
  }

  /* For a LEFT OUTER JOIN, generate code that will record the fact that
  ** at least one row of the right table has matched the left table.  
  */
  if( pLevel->iLeftJoin ){
    pLevel->addrFirst = sqlite4VdbeCurrentAddr(v);
    sqlite4VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
    VdbeComment((v, "record LEFT JOIN hit"));
    sqlite4ExprCacheClear(pParse);
    for(pTerm=pWC->a, j=0; j<pWC->nTerm; j++, pTerm++){
      testcase( pTerm->wtFlags & TERM_VIRTUAL );  /* IMP: R-30575-11662 */
      testcase( pTerm->wtFlags & TERM_CODED );
      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
      if( (pTerm->prereqAll & newNotReady)!=0 ){
        assert( pWInfo->untestedTerms );
        continue;
      }
      assert( pTerm->pExpr );
      sqlite4ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE4_JUMPIFNULL);
      pTerm->wtFlags |= TERM_CODED;
    }
  }
  sqlite4ReleaseTempReg(pParse, iReleaseReg);

  return newNotReady;
}

#ifdef WHERETRACE_ENABLED
/*
** Print a WhereLoop object for debugging purposes
*/
static void whereLoopPrint(WhereLoop *p, SrcList *pTabList){
  int nb = 1+(pTabList->nSrc+7)/8;
  struct SrcListItem *pItem = pTabList->a + p->iTab;
  Table *pTab = pItem->pTab;
  sqlite4DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
                     p->iTab, nb, p->maskSelf, nb, p->prereq);
  sqlite4DebugPrintf(" %12s",
                     pItem->zAlias ? pItem->zAlias : pTab->zName);
  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
    if( p->u.btree.pIndex ){
      const char *zName = p->u.btree.pIndex->zName;
      if( zName==0 ) zName = "ipk";
      if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){
        int i = sqlite4Strlen30(zName) - 1;
        while( zName[i]!='_' ) i--;
        zName += i;
      }
      sqlite4DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq);
    }else{
      sqlite4DebugPrintf("%20s","");
    }
  }else{
    char *z;
    if( p->u.vtab.idxStr ){
      z = sqlite4_mprintf(0, "(%d,\"%s\",%x)",
                p->u.vtab.idxNum, p->u.vtab.idxStr, p->u.vtab.omitMask);
    }else{
      z = sqlite4_mprintf(0, "(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask);
    }
    sqlite4DebugPrintf(" %-19s", z);
    sqlite4_free(0, z);
  }
  sqlite4DebugPrintf(" f %04x N %d", p->wsFlags, p->nLTerm);
  sqlite4DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut);
}
#endif

/*
** Convert bulk memory into a valid WhereLoop that can be passed
** to whereLoopClear harmlessly.
*/
static void whereLoopInit(WhereLoop *p){
  p->aLTerm = p->aLTermSpace;
  p->nLTerm = 0;
  p->nLSlot = ArraySize(p->aLTermSpace);
  p->wsFlags = 0;
}

/*
** Clear the WhereLoop.u union.  Leave WhereLoop.pLTerm intact.
*/
static void whereLoopClearUnion(sqlite4 *db, WhereLoop *p){
  if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){
    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){
#if 0
      sqlite4_free(p->u.vtab.idxStr);
#endif
      p->u.vtab.needFree = 0;
      p->u.vtab.idxStr = 0;
    }else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){
      sqlite4DbFree(db, p->u.btree.pIndex->zColAff);
      sqlite4DbFree(db, p->u.btree.pIndex);
      p->u.btree.pIndex = 0;
    }
  }
}

/*
** Deallocate internal memory used by a WhereLoop object
*/
static void whereLoopClear(sqlite4 *db, WhereLoop *p){
  if( p->aLTerm!=p->aLTermSpace ) sqlite4DbFree(db, p->aLTerm);
  whereLoopClearUnion(db, p);
  whereLoopInit(p);
}

/*
** Increase the memory allocation for pLoop->aLTerm[] to be at least n.
*/
static int whereLoopResize(sqlite4 *db, WhereLoop *p, int n){
  WhereTerm **paNew;
  if( p->nLSlot>=n ) return SQLITE4_OK;
  n = (n+7)&~7;
  paNew = sqlite4DbMallocRaw(db, sizeof(p->aLTerm[0])*n);
  if( paNew==0 ) return SQLITE4_NOMEM;
  memcpy(paNew, p->aLTerm, sizeof(p->aLTerm[0])*p->nLSlot);
  if( p->aLTerm!=p->aLTermSpace ) sqlite4DbFree(db, p->aLTerm);
  p->aLTerm = paNew;
  p->nLSlot = n;
  return SQLITE4_OK;
}

/*




** Transfer content from the second pLoop into the first.
*/


static int whereLoopXfer(sqlite4 *db, WhereLoop *pTo, WhereLoop *pFrom){
  if( whereLoopResize(db, pTo, pFrom->nLTerm) ) return SQLITE4_NOMEM;
  whereLoopClearUnion(db, pTo);
  memcpy(pTo, pFrom, WHERE_LOOP_XFER_SZ);
  memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0]));
  if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){
    pFrom->u.vtab.needFree = 0;
  }else if( (pFrom->wsFlags & WHERE_AUTO_INDEX)!=0 ){
    pFrom->u.btree.pIndex = 0;
  }
  return SQLITE4_OK;
}

/*
** Delete a WhereLoop object
*/
static void whereLoopDelete(sqlite4 *db, WhereLoop *p){
  whereLoopClear(db, p);
  sqlite4DbFree(db, p);
}

/*
** Free a WhereInfo structure
*/
static void whereInfoFree(sqlite4 *db, WhereInfo *pWInfo){
  if( ALWAYS(pWInfo) ){
    whereClauseClear(&pWInfo->sWC);
    while( pWInfo->pLoops ){
      WhereLoop *p = pWInfo->pLoops;
      pWInfo->pLoops = p->pNextLoop;
      whereLoopDelete(db, p);
    }
    sqlite4DbFree(db, pWInfo);
  }
}

/*
** Insert or replace a WhereLoop entry using the template supplied.
**
** An existing WhereLoop entry might be overwritten if the new template
** is better and has fewer dependencies.  Or the template will be ignored
** and no insert will occur if an existing WhereLoop is faster and has
** fewer dependencies than the template.  Otherwise a new WhereLoop is
** added based on the template.
**
** If pBuilder->pBest is not NULL then we only care about the very
** best template and that template should be stored in pBuilder->pBest.
** If pBuilder->pBest is NULL then a list of the best templates are stored
** in pBuilder->pWInfo->pLoops.
**
** When accumulating multiple loops (when pBuilder->pBest is NULL) we
** still might overwrite similar loops with the new template if the
** template is better.  Loops may be overwritten if the following 
** conditions are met:
**
**    (1)  They have the same iTab.
**    (2)  They have the same iSortIdx.
**    (3)  The template has same or fewer dependencies than the current loop
**    (4)  The template has the same or lower cost than the current loop
**    (5)  The template uses more terms of the same index but has no additional
**         dependencies          
*/
static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
  WhereLoop **ppPrev, *p, *pNext = 0;
  WhereInfo *pWInfo = pBuilder->pWInfo;
  sqlite4 *db = pWInfo->pParse->db;

  assert( pTemplate->u.btree.pIndex || !(pTemplate->wsFlags & WHERE_INDEXED) );

  /* If pBuilder->pBest is defined, then only keep track of the single
  ** best WhereLoop.  pBuilder->pBest->maskSelf==0 indicates that no
  ** prior WhereLoops have been evaluated and that the current pTemplate
  ** is therefore the first and hence the best and should be retained.
  */
  if( (p = pBuilder->pBest)!=0 ){
    if( p->maskSelf!=0 ){
      WhereCost rCost = whereCostAdd(p->rRun,p->rSetup);
      WhereCost rTemplate = whereCostAdd(pTemplate->rRun,pTemplate->rSetup);
      if( rCost < rTemplate ){
        testcase( rCost==rTemplate-1 );
        goto whereLoopInsert_noop;
      }
      if( rCost==rTemplate && (p->prereq & pTemplate->prereq)==p->prereq ){
        goto whereLoopInsert_noop;
      }
    }
#if WHERETRACE_ENABLED
    if( sqlite4WhereTrace & 0x8 ){
      sqlite4DebugPrintf(p->maskSelf==0 ? "ins-init: " : "ins-best: ");
      whereLoopPrint(pTemplate, pWInfo->pTabList);
    }
#endif
    whereLoopXfer(db, p, pTemplate);
    return SQLITE4_OK;
  }

  /* Search for an existing WhereLoop to overwrite, or which takes
  ** priority over pTemplate.
  */
  for(ppPrev=&pWInfo->pLoops, p=*ppPrev; p; ppPrev=&p->pNextLoop, p=*ppPrev){
    if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
      /* If either the iTab or iSortIdx values for two WhereLoop are different
      ** then those WhereLoops need to be considered separately.  Neither is
      ** a candidate to replace the other. */
      continue;
    }
    /* In the current implementation, the rSetup value is either zero
    ** or the cost of building an automatic index (NlogN) and the NlogN
    ** is the same for compatible WhereLoops. */
    assert( p->rSetup==0 || pTemplate->rSetup==0 
                 || p->rSetup==pTemplate->rSetup );

    /* whereLoopAddBtree() always generates and inserts the automatic index
    ** case first.  Hence compatible candidate WhereLoops never have a larger
    ** rSetup. Call this SETUP-INVARIANT */
    assert( p->rSetup>=pTemplate->rSetup );

    if( (p->prereq & pTemplate->prereq)==p->prereq
     && p->rSetup<=pTemplate->rSetup
     && p->rRun<=pTemplate->rRun
    ){
      /* This branch taken when p is equal or better than pTemplate in 
      ** all of (1) dependences (2) setup-cost, and (3) run-cost. */
      assert( p->rSetup==pTemplate->rSetup );
      if( p->nLTerm<pTemplate->nLTerm
       && (p->wsFlags & WHERE_INDEXED)!=0
       && (pTemplate->wsFlags & WHERE_INDEXED)!=0
       && p->u.btree.pIndex==pTemplate->u.btree.pIndex
       && p->prereq==pTemplate->prereq
      ){
        /* Overwrite an existing WhereLoop with an similar one that uses
        ** more terms of the index */
        pNext = p->pNextLoop;
        break;
      }else{
        /* pTemplate is not helpful.
        ** Return without changing or adding anything */
        goto whereLoopInsert_noop;
      }
    }
    if( (p->prereq & pTemplate->prereq)==pTemplate->prereq
     && p->rRun>=pTemplate->rRun
     && ALWAYS(p->rSetup>=pTemplate->rSetup) /* See SETUP-INVARIANT above */
    ){
      /* Overwrite an existing WhereLoop with a better one: one that is
      ** better at one of (1) dependences, (2) setup-cost, or (3) run-cost
      ** and is no worse in any of those categories. */
      pNext = p->pNextLoop;
      break;
    }
  }

  /* If we reach this point it means that either p[] should be overwritten
  ** with pTemplate[] if p[] exists, or if p==NULL then allocate a new
  ** WhereLoop and insert it.
  */
#if WHERETRACE_ENABLED
  if( sqlite4WhereTrace & 0x8 ){
    if( p!=0 ){
      sqlite4DebugPrintf("ins-del:  ");
      whereLoopPrint(p, pWInfo->pTabList);
    }
    sqlite4DebugPrintf("ins-new:  ");
    whereLoopPrint(pTemplate, pWInfo->pTabList);
  }
#endif
  if( p==0 ){
    p = sqlite4DbMallocRaw(db, sizeof(WhereLoop));
    if( p==0 ) return SQLITE4_NOMEM;
    whereLoopInit(p);
  }
  whereLoopXfer(db, p, pTemplate);
  p->pNextLoop = pNext;
  *ppPrev = p;
  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
    Index *pIndex = p->u.btree.pIndex;
    if( pIndex && pIndex->tnum==0 ){
      p->u.btree.pIndex = 0;
    }
  }
  return SQLITE4_OK;

  /* Jump here if the insert is a no-op */
whereLoopInsert_noop:
#if WHERETRACE_ENABLED
  if( sqlite4WhereTrace & 0x8 ){
    sqlite4DebugPrintf(pBuilder->pBest ? "ins-skip: " : "ins-noop: ");
    whereLoopPrint(pTemplate, pWInfo->pTabList);
  }
#endif
  return SQLITE4_OK;  
}


/*
** We have so far matched pBuilder->pNew->u.btree.nEq terms of the index pIndex.
** Try to match one more.
*/
static int whereLoopAddBtreeIndex(
  WhereLoopBuilder *pBuilder,     /* The WhereLoop factory */
  struct SrcListItem *pSrc,      /* FROM clause term being analyzed */
  Index *pProbe,                  /* An index on pSrc */
  WhereCost nInMul                /* log(Number of iterations due to IN) */
){
  WhereInfo *pWInfo = pBuilder->pWInfo;  /* WHERE analyse context */
  Parse *pParse = pWInfo->pParse;        /* Parsing context */
  sqlite4 *db = pParse->db;       /* Database connection malloc context */
  WhereLoop *pNew;                /* Template WhereLoop under construction */
  WhereTerm *pTerm;               /* A WhereTerm under consideration */
  int opMask;                     /* Valid operators for constraints */
  WhereScan scan;                 /* Iterator for WHERE terms */
  Bitmask saved_prereq;           /* Original value of pNew->prereq */
  u16 saved_nLTerm;               /* Original value of pNew->nLTerm */
  int saved_nEq;                  /* Original value of pNew->u.btree.nEq */
  u32 saved_wsFlags;              /* Original value of pNew->wsFlags */
  WhereCost saved_nOut;           /* Original value of pNew->nOut */
  int iCol;                       /* Index of the column in the table */
  int rc = SQLITE4_OK;             /* Return code */
  WhereCost nRowEst;              /* Estimated index selectivity */
  WhereCost rLogSize;             /* Logarithm of table size */
  WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */

  assert( pProbe->eIndexType==SQLITE4_INDEX_USER
       || pProbe->eIndexType==SQLITE4_INDEX_UNIQUE
       || pProbe->eIndexType==SQLITE4_INDEX_PRIMARYKEY
  );

  pNew = pBuilder->pNew;
  if( db->mallocFailed ) return SQLITE4_NOMEM;

  assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 );
  assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 );
  if( pNew->wsFlags & WHERE_BTM_LIMIT ){
    opMask = WO_LT|WO_LE;
  }else if( pProbe->tnum<=0 || (pSrc->jointype & JT_LEFT)!=0 ){
    opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE;
  }else{
    opMask = WO_EQ|WO_IN|WO_ISNULL|WO_GT|WO_GE|WO_LT|WO_LE;
  }
  if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);

  if( pNew->u.btree.nEq < pProbe->nColumn ){
    iCol = pProbe->aiColumn[pNew->u.btree.nEq];
    nRowEst = whereCost(pProbe->aiRowEst[pNew->u.btree.nEq+1]);
    if( nRowEst==0 && pProbe->onError==OE_None ) nRowEst = 1;
  }else if( pProbe->eIndexType!=SQLITE4_INDEX_PRIMARYKEY ){
    Index *pPk;
    pPk = sqlite4FindPrimaryKey(pProbe->pTable, 0);
    iCol = idxColumnNumber(pProbe, pPk, pNew->u.btree.nEq);
    nRowEst = 0;
  }else{
    return SQLITE4_OK;
  }
  assert( iCol>=-1 );
  pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, iCol,
                        opMask, pProbe);
  saved_nEq = pNew->u.btree.nEq;
  saved_nLTerm = pNew->nLTerm;
  saved_wsFlags = pNew->wsFlags;
  saved_prereq = pNew->prereq;
  saved_nOut = pNew->nOut;
  pNew->rSetup = 0;
  rLogSize = estLog(whereCost(pProbe->aiRowEst[0]));
  for(; rc==SQLITE4_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
    int nIn = 0;
    if( pTerm->prereqRight & pNew->maskSelf ) continue;
#ifdef SQLITE4_ENABLE_STAT3
    if( (pTerm->wtFlags & TERM_VNULL)!=0 && pSrc->pTab->aCol[iCol].notNull ){
      continue; /* skip IS NOT NULL constraints on a NOT NULL column */
    }
#endif
    pNew->wsFlags = saved_wsFlags;
    pNew->u.btree.nEq = saved_nEq;
    pNew->nLTerm = saved_nLTerm;
    if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
    pNew->aLTerm[pNew->nLTerm++] = pTerm;
    pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
    pNew->rRun = rLogSize; /* Baseline cost is log2(N).  Adjustments below */
    if( pTerm->eOperator & WO_IN ){
      Expr *pExpr = pTerm->pExpr;
      pNew->wsFlags |= WHERE_COLUMN_IN;
      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        /* "x IN (SELECT ...)":  TUNING: the SELECT returns 25 rows */
        nIn = 46;  assert( 46==whereCost(25) );
      }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
        /* "x IN (value, value, ...)" */
        nIn = whereCost(pExpr->x.pList->nExpr);
      }
      pNew->rRun += nIn;
      pNew->u.btree.nEq++;
      pNew->nOut = nRowEst + nInMul + nIn;
    }else if( pTerm->eOperator & (WO_EQ) ){
      assert( (pNew->wsFlags & (WHERE_COLUMN_NULL|WHERE_COLUMN_IN))!=0
                  || nInMul==0 );
      pNew->wsFlags |= WHERE_COLUMN_EQ;
      if( iCol<0  
       || (pProbe->onError!=OE_None && nInMul==0
           && pNew->u.btree.nEq==pProbe->nColumn-1)
      ){
        assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 );
        pNew->wsFlags |= WHERE_ONEROW;
      }
      pNew->u.btree.nEq++;
      pNew->nOut = nRowEst + nInMul;
    }else if( pTerm->eOperator & (WO_ISNULL) ){
      pNew->wsFlags |= WHERE_COLUMN_NULL;
      pNew->u.btree.nEq++;
      /* TUNING: IS NULL selects 2 rows */
      nIn = 10;  assert( 10==whereCost(2) );
      pNew->nOut = nRowEst + nInMul + nIn;
    }else if( pTerm->eOperator & (WO_GT|WO_GE) ){
      testcase( pTerm->eOperator & WO_GT );
      testcase( pTerm->eOperator & WO_GE );
      pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
      pBtm = pTerm;
      pTop = 0;
    }else{
      assert( pTerm->eOperator & (WO_LT|WO_LE) );
      testcase( pTerm->eOperator & WO_LT );
      testcase( pTerm->eOperator & WO_LE );
      pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT;
      pTop = pTerm;
      pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ?
                     pNew->aLTerm[pNew->nLTerm-2] : 0;
    }
    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
      /* Adjust nOut and rRun for STAT3 range values */
      WhereCost rDiv;
      whereRangeScanEst(pParse, pProbe, pNew->u.btree.nEq,
                        pBtm, pTop, &rDiv);
      pNew->nOut = saved_nOut>rDiv+10 ? saved_nOut - rDiv : 10;
    }
#ifdef SQLITE4_ENABLE_STAT3
    if( pNew->u.btree.nEq==1 && pProbe->nSample
     &&  OptimizationEnabled(db, SQLITE4_Stat3) ){
      tRowcnt nOut = 0;
      if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){
        testcase( pTerm->eOperator & WO_EQ );
        testcase( pTerm->eOperator & WO_ISNULL );
        rc = whereEqualScanEst(pParse, pProbe, pTerm->pExpr->pRight, &nOut);
      }else if( (pTerm->eOperator & WO_IN)
             &&  !ExprHasProperty(pTerm->pExpr, EP_xIsSelect)  ){
        rc = whereInScanEst(pParse, pProbe, pTerm->pExpr->x.pList, &nOut);
      }
      if( rc==SQLITE4_OK ) pNew->nOut = whereCost(nOut);
    }
#endif
    if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
      /* Each row involves a step of the index, then a binary search of
      ** the main table */
      pNew->rRun =  whereCostAdd(pNew->rRun, rLogSize>27 ? rLogSize-17 : 10);
    }
    /* Step cost for each output row */
    pNew->rRun = whereCostAdd(pNew->rRun, pNew->nOut);
    /* TBD: Adjust nOut for additional constraints */
    rc = whereLoopInsert(pBuilder, pNew);
    if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0
     && pNew->u.btree.nEq<(pProbe->nColumn + (pProbe->zName!=0))
    ){
      whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn);
    }
  }
  pNew->prereq = saved_prereq;
  pNew->u.btree.nEq = saved_nEq;
  pNew->wsFlags = saved_wsFlags;
  pNew->nOut = saved_nOut;
  pNew->nLTerm = saved_nLTerm;
  return rc;
}

/*
** Return True if it is possible that pIndex might be useful in
** implementing the ORDER BY clause in pBuilder.
**
** Return False if pBuilder does not contain an ORDER BY clause or
** if there is no way for pIndex to be useful in implementing that
** ORDER BY clause.
*/
static int indexMightHelpWithOrderBy(
  WhereLoopBuilder *pBuilder,
  Index *pIndex,
  int iCursor
){
  ExprList *pOB;
  int ii, jj;

  if( pIndex->bUnordered ) return 0;
  if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
  for(ii=0; ii<pOB->nExpr; ii++){
    Expr *pExpr = sqlite4ExprSkipCollate(pOB->a[ii].pExpr);
    if( pExpr->op!=TK_COLUMN ) return 0;
    if( pExpr->iTable==iCursor ){
      for(jj=0; jj<pIndex->nColumn; jj++){
        if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
      }
    }
  }
  return 0;
}

/*
** Return a bitmask where 1s indicate that the corresponding column of
** the table is used by an index.  Only the first 63 columns are considered.
*/
static Bitmask columnsInIndex(Index *pIdx){
  Bitmask m = 0;
  int j;

  for(j=pIdx->nColumn-1; j>=0; j--){
    int x = pIdx->aiColumn[j];
    testcase( x==BMS-1 );
    testcase( x==BMS-2 );
    if( x<BMS-1 ) m |= MASKBIT(x);
  }
  return m;
}


/*
** Add all WhereLoop objects for a single table of the join where the table
** is idenfied by pBuilder->pNew->iTab.  That table is guaranteed to be
** a b-tree table, not a virtual table.
*/
static int whereLoopAddBtree(
  WhereLoopBuilder *pBuilder, /* WHERE clause information */
  Bitmask mExtra              /* Extra prerequesites for using this table */
){
  WhereInfo *pWInfo;          /* WHERE analysis context */
  Index *pProbe;              /* An index we are evaluating */
  Index *pPk;                 /* Primary key index for table pSrc */
  tRowcnt aiRowEstPk[2];      /* The aiRowEst[] value for the sPk index */
  int aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
  SrcList *pTabList;          /* The FROM clause */
  struct SrcListItem *pSrc;   /* The FROM clause btree term to add */
  WhereLoop *pNew;            /* Template WhereLoop object */
  int rc = SQLITE4_OK;        /* Return code */
  int iSortIdx = 1;           /* Index number */
  int b;                      /* A boolean value */
  WhereCost rSize;            /* number of rows in the table */
  WhereCost rLogSize;         /* Logarithm of the number of rows in the table */
  
  pNew = pBuilder->pNew;
  pWInfo = pBuilder->pWInfo;
  pTabList = pWInfo->pTabList;
  pSrc = pTabList->a + pNew->iTab;
  assert( !IsVirtual(pSrc->pTab) );
  pPk = sqlite4FindPrimaryKey(pSrc->pTab, 0);

  if( pSrc->pIndex ){
    /* An INDEXED BY clause specifies a particular index to use */
    pProbe = pSrc->pIndex;
  }else if( pSrc->notIndexed ){
    /* A NOT INDEXED clause means use the PK index */
    pProbe = pPk;
  }else{
    /* Otherwise, consider all indexes */
    pProbe = pSrc->pTab->pIndex;
  }

  rSize = whereCost(pSrc->pTab->nRowEst);
  rLogSize = estLog(rSize);

#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
  /* Automatic indexes */
  if( !pBuilder->pBest
   && (pWInfo->pParse->db->flags & SQLITE4_AutoIndex)!=0
   && pSrc->pIndex==0
#if 0
   && !pSrc->viaCoroutine
#endif
   && !pSrc->notIndexed
   && !pSrc->isCorrelated
  ){
    /* Generate auto-index WhereLoops */
    WhereClause *pWC = pBuilder->pWC;
    WhereTerm *pTerm;
    WhereTerm *pWCEnd = pWC->a + pWC->nTerm;
    for(pTerm=pWC->a; rc==SQLITE4_OK && pTerm<pWCEnd; pTerm++){
      if( pTerm->prereqRight & pNew->maskSelf ) continue;
      if( termCanDriveIndex(pTerm, pSrc, 0) ){
        pNew->u.btree.nEq = 1;
        pNew->u.btree.pIndex = 0;
        pNew->nLTerm = 1;
        pNew->aLTerm[0] = pTerm;
        /* TUNING: One-time cost for computing the automatic index is
        ** approximately 7*N*log2(N) where N is the number of rows in
        ** the table being indexed. */
        pNew->rSetup = rLogSize + rSize + 28;  assert( 28==whereCost(7) );
        /* TUNING: Each index lookup yields 20 rows in the table.  This
        ** is more than the usual guess of 10 rows, since we have no way
        ** of knowning how selective the index will ultimately be.  It would
        ** not be unreasonable to make this value much larger. */
        pNew->nOut = 43;  assert( 43==whereCost(20) );
        pNew->rRun = whereCostAdd(rLogSize,pNew->nOut);
        pNew->wsFlags = WHERE_AUTO_INDEX;
        pNew->prereq = mExtra | pTerm->prereqRight;
        rc = whereLoopInsert(pBuilder, pNew);
      }
    }
  }
#endif /* ifndef SQLITE4_OMIT_AUTOMATIC_INDEX */

  /* If this table has no primary key, then it is either a materialized
  ** view or ephemeral table. Either way, add a WhereLoop for a full-scan 
  ** of it.  */
  if( pPk==0 ){
    assert( pSrc->pTab->pSelect || (pSrc->pTab->tabFlags & TF_Ephemeral) );
    pNew->u.btree.nEq = 0;
    pNew->nLTerm = 0;
    pNew->iSortIdx = 0;
    pNew->rSetup = 0;
    pNew->prereq = mExtra;
    pNew->nOut = rSize;
    pNew->u.btree.pIndex = 0;
    pNew->wsFlags = 0;
    pNew->rRun = whereCostAdd(rSize,rLogSize) + 16;
    rc = whereLoopInsert(pBuilder, pNew);
  }

  /* Loop through the set of indices being considered. */
  for(; rc==SQLITE4_OK && pProbe; pProbe=pProbe->pNext, iSortIdx++){

    if( pProbe->eIndexType==SQLITE4_INDEX_FTS5 ) continue;
    assert( pProbe->tnum>0 );

    pNew->u.btree.nEq = 0;
    pNew->nLTerm = 0;
    pNew->rSetup = 0;
    pNew->prereq = mExtra;
    pNew->nOut = rSize;
    pNew->u.btree.pIndex = pProbe;
    pNew->wsFlags = WHERE_INDEXED;

    b = indexMightHelpWithOrderBy(pBuilder, pProbe, pSrc->iCursor);
    /* The ONEPASS_DESIRED flags never occurs together with ORDER BY */
    assert( (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || b==0 );
    pNew->iSortIdx = b ? iSortIdx : 0;

    if( pProbe==pPk || b ){
      /* Add a WhereLoop for full-scan via primary key index. */

      /* TUNING: Cost of full table scan is 3*(N + log2(N)).
      **  +  The extra 3 factor is to encourage the use of indexed lookups
      **     over full scans.  A smaller constant 2 is used for covering
      **     index scans so that a covering index scan will be favored over
      **     a table scan. */
      /* TODO: Fix tuning for src4 as described in comment immediately above. */
      pNew->rRun = whereCostAdd(rSize,rLogSize) + 16;
      rc = whereLoopInsert(pBuilder, pNew);
      if( rc ) break;
    }

    rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0);

    /* If there was an INDEXED BY or NOT INDEXED clause, then only one
    ** index is considered. */
    if( pSrc->pIndex || pSrc->notIndexed ) break;
  }
  return rc;
}

#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Add all WhereLoop objects for a table of the join identified by
** pBuilder->pNew->iTab.  That table is guaranteed to be a virtual table.
*/
static int whereLoopAddVirtual(
  WhereLoopBuilder *pBuilder   /* WHERE clause information */
){
  WhereInfo *pWInfo;           /* WHERE analysis context */
  Parse *pParse;               /* The parsing context */
  WhereClause *pWC;            /* The WHERE clause */
  struct SrcListItem *pSrc;   /* The FROM clause term to search */
  Table *pTab;
  sqlite4 *db;
  sqlite4_index_info *pIdxInfo;

  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int i, j;
  int iTerm, mxTerm;
  int nConstraint;
  int seenIn = 0;              /* True if an IN operator is seen */
  int seenVar = 0;             /* True if a non-constant constraint is seen */
  int iPhase;                  /* 0: const w/o IN, 1: const, 2: no IN,  2: IN */
  WhereLoop *pNew;
  int rc = SQLITE4_OK;

  pWInfo = pBuilder->pWInfo;
  pParse = pWInfo->pParse;
  db = pParse->db;
  pWC = pBuilder->pWC;
  pNew = pBuilder->pNew;
  pSrc = &pWInfo->pTabList->a[pNew->iTab];
  pTab = pSrc->pTab;
  assert( IsVirtual(pTab) );
  pIdxInfo = allocateIndexInfo(pParse, pWC, pSrc, pBuilder->pOrderBy);
  if( pIdxInfo==0 ) return SQLITE4_NOMEM;
  pNew->prereq = 0;
  pNew->rSetup = 0;
  pNew->wsFlags = WHERE_VIRTUALTABLE;
  pNew->nLTerm = 0;
  pNew->u.vtab.needFree = 0;
  pUsage = pIdxInfo->aConstraintUsage;
  nConstraint = pIdxInfo->nConstraint;
  if( whereLoopResize(db, pNew, nConstraint) ){
    sqlite4DbFree(db, pIdxInfo);
    return SQLITE4_NOMEM;
  }

  for(iPhase=0; iPhase<=3; iPhase++){
    if( !seenIn && (iPhase&1)!=0 ){
      iPhase++;
      if( iPhase>3 ) break;
    }
    if( !seenVar && iPhase>1 ) break;
    pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
    for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
      j = pIdxCons->iTermOffset;
      pTerm = &pWC->a[j];
      switch( iPhase ){
        case 0:    /* Constants without IN operator */
          pIdxCons->usable = 0;
          if( (pTerm->eOperator & WO_IN)!=0 ){
            seenIn = 1;
          }
          if( pTerm->prereqRight!=0 ){
            seenVar = 1;
          }else if( (pTerm->eOperator & WO_IN)==0 ){
            pIdxCons->usable = 1;
          }
          break;
        case 1:    /* Constants with IN operators */
          assert( seenIn );
          pIdxCons->usable = (pTerm->prereqRight==0);
          break;
        case 2:    /* Variables without IN */
          assert( seenVar );
          pIdxCons->usable = (pTerm->eOperator & WO_IN)==0;
          break;
        default:   /* Variables with IN */
          assert( seenVar && seenIn );
          pIdxCons->usable = 1;
          break;
      }
    }
    memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
    if( pIdxInfo->needToFreeIdxStr ) sqlite4_free(pIdxInfo->idxStr);
    pIdxInfo->idxStr = 0;
    pIdxInfo->idxNum = 0;
    pIdxInfo->needToFreeIdxStr = 0;
    pIdxInfo->orderByConsumed = 0;
    pIdxInfo->estimatedCost = SQLITE4_BIG_DBL / (double)2;
    rc = vtabBestIndex(pParse, pTab, pIdxInfo);
    if( rc ) goto whereLoopAddVtab_exit;
    pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
    pNew->prereq = 0;
    mxTerm = -1;
    assert( pNew->nLSlot>=nConstraint );
    for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0;
    pNew->u.vtab.omitMask = 0;
    for(i=0; i<nConstraint; i++, pIdxCons++){
      if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
        j = pIdxCons->iTermOffset;
        if( iTerm>=nConstraint
         || j<0
         || j>=pWC->nTerm
         || pNew->aLTerm[iTerm]!=0
        ){
          rc = SQLITE4_ERROR;
          sqlite4ErrorMsg(pParse, "%s.xBestIndex() malfunction", pTab->zName);
          goto whereLoopAddVtab_exit;
        }
        testcase( iTerm==nConstraint-1 );
        testcase( j==0 );
        testcase( j==pWC->nTerm-1 );
        pTerm = &pWC->a[j];
        pNew->prereq |= pTerm->prereqRight;
        assert( iTerm<pNew->nLSlot );
        pNew->aLTerm[iTerm] = pTerm;
        if( iTerm>mxTerm ) mxTerm = iTerm;
        testcase( iTerm==15 );
        testcase( iTerm==16 );
        if( iTerm<16 && pUsage[i].omit ) pNew->u.vtab.omitMask |= 1<<iTerm;
        if( (pTerm->eOperator & WO_IN)!=0 ){
          if( pUsage[i].omit==0 ){
            /* Do not attempt to use an IN constraint if the virtual table
            ** says that the equivalent EQ constraint cannot be safely omitted.
            ** If we do attempt to use such a constraint, some rows might be
            ** repeated in the output. */
            break;
          }
          /* A virtual table that is constrained by an IN clause may not
          ** consume the ORDER BY clause because (1) the order of IN terms
          ** is not necessarily related to the order of output terms and
          ** (2) Multiple outputs from a single IN value will not merge
          ** together.  */
          pIdxInfo->orderByConsumed = 0;
        }
      }
    }
    if( i>=nConstraint ){
      pNew->nLTerm = mxTerm+1;
      assert( pNew->nLTerm<=pNew->nLSlot );
      pNew->u.vtab.idxNum = pIdxInfo->idxNum;
      pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
      pIdxInfo->needToFreeIdxStr = 0;
      pNew->u.vtab.idxStr = pIdxInfo->idxStr;
      pNew->u.vtab.isOrdered = (u8)((pIdxInfo->nOrderBy!=0)
                                     && pIdxInfo->orderByConsumed);
      pNew->rSetup = 0;
      pNew->rRun = whereCostFromDouble(pIdxInfo->estimatedCost);
      /* TUNING: Every virtual table query returns 25 rows */
      pNew->nOut = 46;  assert( 46==whereCost(25) );
      whereLoopInsert(pBuilder, pNew);
      if( pNew->u.vtab.needFree ){
        sqlite4_free(pNew->u.vtab.idxStr);
        pNew->u.vtab.needFree = 0;
      }
    }
  }  

whereLoopAddVtab_exit:
  if( pIdxInfo->needToFreeIdxStr ) sqlite4_free(pIdxInfo->idxStr);
  sqlite4DbFree(db, pIdxInfo);
  return rc;
}
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

/*
** Add WhereLoop entries to handle OR terms.  This works for either
** btrees or virtual tables.
*/
static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){
  WhereInfo *pWInfo = pBuilder->pWInfo;
  WhereClause *pWC;
  WhereLoop *pNew;
  WhereTerm *pTerm, *pWCEnd;
  int rc = SQLITE4_OK;
  int iCur;
  WhereClause tempWC;
  WhereLoopBuilder sSubBuild;
  WhereLoop sBest;
  struct SrcListItem *pItem;
  
  pWC = pBuilder->pWC;
  if( pWInfo->wctrlFlags & WHERE_AND_ONLY ) return SQLITE4_OK;
  pWCEnd = pWC->a + pWC->nTerm;
  pNew = pBuilder->pNew;

  for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE4_OK; pTerm++){
    if( (pTerm->eOperator & WO_OR)!=0
     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      WhereCost rTotal = 0;
      WhereCost nRow = 0;
      Bitmask prereq = mExtra;
    
      whereLoopInit(&sBest);
      pItem = pWInfo->pTabList->a + pNew->iTab;
      iCur = pItem->iCursor;
      sSubBuild = *pBuilder;
      sSubBuild.pOrderBy = 0;
      sSubBuild.pBest = &sBest;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
        if( (pOrTerm->eOperator & WO_AND)!=0 ){
          sSubBuild.pWC = &pOrTerm->u.pAndInfo->wc;
        }else if( pOrTerm->leftCursor==iCur ){
          tempWC.pWInfo = pWC->pWInfo;
          tempWC.pOuter = pWC;
          tempWC.op = TK_AND;
          tempWC.nTerm = 1;
          tempWC.a = pOrTerm;
          sSubBuild.pWC = &tempWC;
        }else{
          continue;
        }
        sBest.maskSelf = 0;
        sBest.rSetup = 0;
        sBest.rRun = 0;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
        if( IsVirtual(pItem->pTab) ){
          rc = whereLoopAddVirtual(&sSubBuild);
        }else
#endif
        {
          rc = whereLoopAddBtree(&sSubBuild, mExtra);
        }
        /* sBest.maskSelf is always zero if an error occurs */
        assert( rc==SQLITE4_OK || sBest.maskSelf==0 );
        if( sBest.maskSelf==0 ) break;
        assert( sBest.rSetup==0 );
        rTotal = whereCostAdd(rTotal, sBest.rRun);
        nRow = whereCostAdd(nRow, sBest.nOut);
        prereq |= sBest.prereq;
      }
      assert( pNew->nLSlot>=1 );
      if( sBest.maskSelf ){
        pNew->nLTerm = 1;
        pNew->aLTerm[0] = pTerm;
        pNew->wsFlags = WHERE_MULTI_OR;
        pNew->rSetup = 0;
        /* TUNING: Multiple by 3.5 for the secondary table lookup */
        pNew->rRun = rTotal + 18; assert( 18==whereCost(7)-whereCost(2) );
        pNew->nOut = nRow;
        pNew->prereq = prereq;
        memset(&pNew->u, 0, sizeof(pNew->u));
        rc = whereLoopInsert(pBuilder, pNew);
      }
      whereLoopClear(pWInfo->pParse->db, &sBest);
    }
  }
  return rc;
}

/*
** Add all WhereLoop objects for all tables 
*/
static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
  WhereInfo *pWInfo = pBuilder->pWInfo;
  Bitmask mExtra = 0;
  Bitmask mPrior = 0;
  int iTab;
  SrcList *pTabList = pWInfo->pTabList;
  struct SrcListItem *pItem;
  sqlite4 *db = pWInfo->pParse->db;
  int nTabList = pWInfo->nLevel;
  int rc = SQLITE4_OK;
  u8 priorJoinType = 0;
  WhereLoop *pNew;

  /* Loop over the tables in the join, from left to right */
  pNew = pBuilder->pNew;
  whereLoopInit(pNew);
  for(iTab=0, pItem=pTabList->a; iTab<nTabList; iTab++, pItem++){
    pNew->iTab = iTab;
    pNew->maskSelf = getMask(&pWInfo->sMaskSet, pItem->iCursor);
    if( ((pItem->jointype|priorJoinType) & (JT_LEFT|JT_CROSS))!=0 ){
      mExtra = mPrior;
    }
    priorJoinType = pItem->jointype;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( IsVirtual(pItem->pTab) ){
      rc = whereLoopAddVirtual(pBuilder);
    }else
#endif
    {
      rc = whereLoopAddBtree(pBuilder, mExtra);
    }
    if( rc==SQLITE4_OK ){
      rc = whereLoopAddOr(pBuilder, mExtra);
    }
    mPrior |= pNew->maskSelf;
    if( rc || db->mallocFailed ) break;
  }
  whereLoopClear(db, pNew);
  return rc;
}

/*
** Examine a WherePath (with the addition of the extra WhereLoop of the 5th
** parameters) to see if it outputs rows in the requested ORDER BY
** (or GROUP BY) without requiring a separate sort operation.  Return:
** 
**    0:  ORDER BY is not satisfied.  Sorting required
**    1:  ORDER BY is satisfied.      Omit sorting
**   -1:  Unknown at this time
**
** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as
** strict.  With GROUP BY and DISTINCT the only requirement is that
** equivalent rows appear immediately adjacent to one another.  GROUP BY
** and DISTINT do not require rows to appear in any particular order as long
** as equivelent rows are grouped together.  Thus for GROUP BY and DISTINCT
** the pOrderBy terms can be matched in any order.  With ORDER BY, the 
** pOrderBy terms must be matched in strict left-to-right order.
*/
static int wherePathSatisfiesOrderBy(
  WhereInfo *pWInfo,    /* The WHERE clause */
  ExprList *pOrderBy,   /* ORDER BY or GROUP BY or DISTINCT clause to check */
  WherePath *pPath,     /* The WherePath to check */
  u16 wctrlFlags,       /* Might contain WHERE_GROUPBY or WHERE_DISTINCTBY */
  u16 nLoop,            /* Number of entries in pPath->aLoop[] */
  WhereLoop *pLast,     /* Add this WhereLoop to the end of pPath->aLoop[] */
  Bitmask *pRevMask     /* OUT: Mask of WhereLoops to run in reverse order */
){
  u8 revSet;            /* True if rev is known */
  u8 rev;               /* Composite sort order */
  u8 revIdx;            /* Index sort order */
  u8 isOrderDistinct;   /* All prior WhereLoops are order-distinct */
  u8 isMatch;           /* iColumn matches a term of the ORDER BY clause */
  u16 nColumn;          /* Number of columns in pIndex */
  u16 nOrderBy;         /* Number terms in the ORDER BY clause */
  int iLoop;            /* Index of WhereLoop in pPath being processed */
  int i, j;             /* Loop counters */
  int iCur;             /* Cursor number for current WhereLoop */
  int iColumn;          /* A column number within table iCur */
  WhereLoop *pLoop = 0; /* Current WhereLoop being processed. */
  WhereTerm *pTerm;     /* A single term of the WHERE clause */
  Expr *pOBExpr;        /* An expression from the ORDER BY clause */
  CollSeq *pColl;       /* COLLATE function from an ORDER BY clause term */
  Index *pIndex;        /* The index associated with pLoop */
  sqlite4 *db = pWInfo->pParse->db;  /* Database connection */
  Bitmask obSat = 0;    /* Mask of ORDER BY terms satisfied so far */
  Bitmask obDone;       /* Mask of all ORDER BY terms */
  Bitmask orderDistinctMask;  /* Mask of all well-ordered loops */
  Bitmask ready;              /* Mask of inner loops */

  /*
  ** We say the WhereLoop is "one-row" if it generates no more than one
  ** row of output.  A WhereLoop is one-row if all of the following are true:
  **  (a) All index columns match with WHERE_COLUMN_EQ.
  **  (b) The index is unique
  ** Any WhereLoop with an WHERE_COLUMN_EQ constraint on the rowid is one-row.
  ** Every one-row WhereLoop will have the WHERE_ONEROW bit set in wsFlags.
  **
  ** We say the WhereLoop is "order-distinct" if the set of columns from
  ** that WhereLoop that are in the ORDER BY clause are different for every
  ** row of the WhereLoop.  Every one-row WhereLoop is automatically
  ** order-distinct.   A WhereLoop that has no columns in the ORDER BY clause
  ** is not order-distinct. To be order-distinct is not quite the same as being
  ** UNIQUE since a UNIQUE column or index can have multiple rows that 
  ** are NULL and NULL values are equivalent for the purpose of order-distinct.
  ** To be order-distinct, the columns must be UNIQUE and NOT NULL.
  **
  ** The rowid for a table is always UNIQUE and NOT NULL so whenever the
  ** rowid appears in the ORDER BY clause, the corresponding WhereLoop is
  ** automatically order-distinct.
  */

  assert( pOrderBy!=0 );

  /* Sortability of virtual tables is determined by the xBestIndex method
  ** of the virtual table itself */
  if( pLast->wsFlags & WHERE_VIRTUALTABLE ){
    testcase( nLoop>0 );  /* True when outer loops are one-row and match 
                          ** no ORDER BY terms */
    return pLast->u.vtab.isOrdered;
  }
  if( nLoop && OptimizationDisabled(db, SQLITE4_OrderByIdxJoin) ) return 0;

  nOrderBy = pOrderBy->nExpr;
  testcase( nOrderBy==BMS-1 );
  if( nOrderBy>BMS-1 ) return 0;  /* Cannot optimize overly large ORDER BYs */
  isOrderDistinct = 1;
  obDone = MASKBIT(nOrderBy)-1;
  orderDistinctMask = 0;
  ready = 0;
  for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){
    if( iLoop>0 ) ready |= pLoop->maskSelf;
    pLoop = iLoop<nLoop ? pPath->aLoop[iLoop] : pLast;
    assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 );
    iCur = pWInfo->pTabList->a[pLoop->iTab].iCursor;

    /* Mark off any ORDER BY term X that is a column in the table of
    ** the current loop for which there is term in the WHERE
    ** clause of the form X IS NULL or X=? that reference only outer
    ** loops.
    */
    for(i=0; i<nOrderBy; i++){
      if( MASKBIT(i) & obSat ) continue;
      pOBExpr = sqlite4ExprSkipCollate(pOrderBy->a[i].pExpr);
      if( pOBExpr->op!=TK_COLUMN ) continue;
      if( pOBExpr->iTable!=iCur ) continue;
      pTerm = findTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
                       ~ready, WO_EQ|WO_ISNULL, 0);
      if( pTerm==0 ) continue;
      if( (pTerm->eOperator&WO_EQ)!=0 && pOBExpr->iColumn>=0 ){
        const char *z1, *z2;
        pColl = sqlite4ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
        if( !pColl ) pColl = db->pDfltColl;
        z1 = pColl->zName;
        pColl = sqlite4ExprCollSeq(pWInfo->pParse, pTerm->pExpr);
        if( !pColl ) pColl = db->pDfltColl;
        z2 = pColl->zName;
        if( sqlite4_stricmp(z1, z2)!=0 ) continue;
      }
      obSat |= MASKBIT(i);
    }

    if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
      Index *pPk = 0;
      if( pLoop->wsFlags & WHERE_IPK ){

        pIndex = 0;
        nColumn = 0;
      }else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
        return 0;
      }else{
        isOrderDistinct = pIndex->onError!=OE_None;
        pPk = sqlite4FindPrimaryKey(pIndex->pTable, 0);
        nColumn = idxColumnCount(pIndex, pPk);
      }

      /* Loop through all columns of the index and deal with the ones
      ** that are not constrained by == or IN.
      */
      rev = revSet = 0;
      for(j=0; j<nColumn; j++){
        u8 bOnce;   /* True to run the ORDER BY search loop */

        /* Skip over == and IS NULL terms */
        if( j<pLoop->u.btree.nEq
         && ((i = pLoop->aLTerm[j]->eOperator) & (WO_EQ|WO_ISNULL))!=0
        ){
          if( i & WO_ISNULL ){
            testcase( isOrderDistinct );
            isOrderDistinct = 0;
          }
          continue;  
        }

        /* Get the column number in the table (iColumn) and sort order
        ** (revIdx) for the j-th column of the index.
        */
        if( j<nColumn ){
          /* Normal index columns */
          iColumn = idxColumnNumber(pIndex, pPk, j);
          revIdx = idxColumnSortOrder(pIndex, pPk, j);
        }else{
          /* The ROWID column at the end */
          assert( j==nColumn );
          iColumn = -1;
          revIdx = 0;


        }

        /* An unconstrained column that might be NULL means that this
        ** WhereLoop is not well-ordered 
        */
        if( isOrderDistinct
         && iColumn>=0
         && j>=pLoop->u.btree.nEq
         && pIndex->pTable->aCol[iColumn].notNull==0
        ){
          isOrderDistinct = 0;
        }

        /* Find the ORDER BY term that corresponds to the j-th column
        ** of the index and and mark that ORDER BY term off 
        */
        bOnce = 1;
        isMatch = 0;
        for(i=0; bOnce && i<nOrderBy; i++){
          if( MASKBIT(i) & obSat ) continue;
          pOBExpr = sqlite4ExprSkipCollate(pOrderBy->a[i].pExpr);
          testcase( wctrlFlags & WHERE_GROUPBY );
          testcase( wctrlFlags & WHERE_DISTINCTBY );
          if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
          if( pOBExpr->op!=TK_COLUMN ) continue;
          if( pOBExpr->iTable!=iCur ) continue;
          if( pOBExpr->iColumn!=iColumn ) continue;
          if( iColumn>=0 ){
            const char *zIdxColl;
            pColl = sqlite4ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
            if( !pColl ) pColl = db->pDfltColl;
            zIdxColl = idxColumnCollation(pIndex, pPk, j);
            if( sqlite4_stricmp(pColl->zName, zIdxColl)!=0 ) continue;
          }
          isMatch = 1;
          break;
        }
        if( isMatch ){
          obSat |= MASKBIT(i);
          if( (pWInfo->wctrlFlags & WHERE_GROUPBY)==0 ){
            /* Make sure the sort order is compatible in an ORDER BY clause.
            ** Sort order is irrelevant for a GROUP BY clause. */
            if( revSet ){
              if( (rev ^ revIdx)!=pOrderBy->a[i].sortOrder ) return 0;
            }else{
              rev = revIdx ^ pOrderBy->a[i].sortOrder;
              if( rev ) *pRevMask |= MASKBIT(iLoop);
              revSet = 1;
            }
          }
        }else{
          /* No match found */
          if( j==0 || j<nColumn ){
            testcase( isOrderDistinct!=0 );
            isOrderDistinct = 0;
          }
          break;
        }
      } /* end Loop over all index columns */

      /* If (j==nColumn), then each column of the index, including any 
      ** appended PK columns, corresponds to either an ORDER BY term or 
      ** equality constraint. Since the PK columns are collectively UNIQUE
      ** and NOT NULL, consider the loop order-distinct.  */
      if( j==nColumn ){
        testcase( isOrderDistinct==0 );
        isOrderDistinct = 1;
      }
    } /* end-if not one-row */

    /* Mark off any other ORDER BY terms that reference pLoop */
    if( isOrderDistinct ){
      orderDistinctMask |= pLoop->maskSelf;
      for(i=0; i<nOrderBy; i++){
        Expr *p;
        if( MASKBIT(i) & obSat ) continue;
        p = pOrderBy->a[i].pExpr;
        if( (exprTableUsage(&pWInfo->sMaskSet, p)&~orderDistinctMask)==0 ){
          obSat |= MASKBIT(i);
        }
      }
    }
  } /* End the loop over all WhereLoops from outer-most down to inner-most */
  if( obSat==obDone ) return 1;
  if( !isOrderDistinct ) return 0;
  return -1;
}

#ifdef WHERETRACE_ENABLED
/* For debugging use only: */
static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){
  static char zName[65];
  int i;
  for(i=0; i<nLoop; i++){ zName[i] = pPath->aLoop[i]->cId; }
  if( pLast ) zName[i++] = pLast->cId;
  zName[i] = 0;
  return zName;
}
#endif


/*
** Given the list of WhereLoop objects at pWInfo->pLoops, this routine
** attempts to find the lowest cost path that visits each WhereLoop
** once.  This path is then loaded into the pWInfo->a[].pWLoop fields.
**
** Assume that the total number of output rows that will need to be sorted
** will be nRowEst (in the 10*log2 representation).  Or, ignore sorting
** costs if nRowEst==0.
**
** Return SQLITE4_OK on success or SQLITE4_NOMEM of a memory allocation
** error occurs.
*/
static int wherePathSolver(WhereInfo *pWInfo, WhereCost nRowEst){
  int mxChoice;             /* Maximum number of simultaneous paths tracked */
  int nLoop;                /* Number of terms in the join */
  Parse *pParse;            /* Parsing context */
  sqlite4 *db;              /* The database connection */
  int iLoop;                /* Loop counter over the terms of the join */
  int ii, jj;               /* Loop counters */
  WhereCost rCost;             /* Cost of a path */
  WhereCost mxCost = 0;        /* Maximum cost of a set of paths */
  WhereCost rSortCost;         /* Cost to do a sort */
  int nTo, nFrom;           /* Number of valid entries in aTo[] and aFrom[] */
  WherePath *aFrom;         /* All nFrom paths at the previous level */
  WherePath *aTo;           /* The nTo best paths at the current level */
  WherePath *pFrom;         /* An element of aFrom[] that we are working on */
  WherePath *pTo;           /* An element of aTo[] that we are working on */
  WhereLoop *pWLoop;        /* One of the WhereLoop objects */
  WhereLoop **pX;           /* Used to divy up the pSpace memory */
  char *pSpace;             /* Temporary memory used by this routine */

  pParse = pWInfo->pParse;
  db = pParse->db;
  nLoop = pWInfo->nLevel;
  /* TUNING: For simple queries, only the best path is tracked.
  ** For 2-way joins, the 5 best paths are followed.
  ** For joins of 3 or more tables, track the 10 best paths */
  mxChoice = (nLoop==1) ? 1 : (nLoop==2 ? 5 : 10);
  assert( nLoop<=pWInfo->pTabList->nSrc );
  WHERETRACE(0x002, ("---- begin solver\n"));

  /* Allocate and initialize space for aTo and aFrom */
  ii = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2;
  pSpace = sqlite4DbMallocRaw(db, ii);
  if( pSpace==0 ) return SQLITE4_NOMEM;
  aTo = (WherePath*)pSpace;
  aFrom = aTo+mxChoice;
  memset(aFrom, 0, sizeof(aFrom[0]));
  pX = (WhereLoop**)(aFrom+mxChoice);
  for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){
    pFrom->aLoop = pX;
  }

  /* Seed the search with a single WherePath containing zero WhereLoops.
  **
  ** TUNING: Do not let the number of iterations go above 25.  If the cost
  ** of computing an automatic index is not paid back within the first 25
  ** rows, then do not use the automatic index. */
  aFrom[0].nRow = MIN(pParse->nQueryLoop, 46);  assert( 46==whereCost(25) );
  nFrom = 1;

  /* Precompute the cost of sorting the final result set, if the caller
  ** to sqlite4WhereBegin() was concerned about sorting */
  rSortCost = 0;
  if( pWInfo->pOrderBy==0 || nRowEst==0 ){
    aFrom[0].isOrderedValid = 1;
  }else{
    /* TUNING: Estimated cost of sorting is N*log2(N) where N is the
    ** number of output rows. */
    rSortCost = nRowEst + estLog(nRowEst);
    WHERETRACE(0x002,("---- sort cost=%-3d\n", rSortCost));
  }

  /* Compute successively longer WherePaths using the previous generation
  ** of WherePaths as the basis for the next.  Keep track of the mxChoice
  ** best paths at each generation */
  for(iLoop=0; iLoop<nLoop; iLoop++){
    nTo = 0;
    for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){
      for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
        Bitmask maskNew;
        Bitmask revMask = 0;
        u8 isOrderedValid = pFrom->isOrderedValid;
        u8 isOrdered = pFrom->isOrdered;
        if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
        if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
        /* At this point, pWLoop is a candidate to be the next loop. 
        ** Compute its cost */
        rCost = whereCostAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
        rCost = whereCostAdd(rCost, pFrom->rCost);
        maskNew = pFrom->maskLoop | pWLoop->maskSelf;
        if( !isOrderedValid ){
          switch( wherePathSatisfiesOrderBy(pWInfo,
                       pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
                       iLoop, pWLoop, &revMask) ){
            case 1:  /* Yes.  pFrom+pWLoop does satisfy the ORDER BY clause */
              isOrdered = 1;
              isOrderedValid = 1;
              break;
            case 0:  /* No.  pFrom+pWLoop will require a separate sort */
              isOrdered = 0;
              isOrderedValid = 1;
              rCost = whereCostAdd(rCost, rSortCost);
              break;
            default: /* Cannot tell yet.  Try again on the next iteration */
              break;
          }
        }else{
          revMask = pFrom->revLoop;
        }
        /* Check to see if pWLoop should be added to the mxChoice best so far */
        for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
          if( pTo->maskLoop==maskNew && pTo->isOrderedValid==isOrderedValid ){
            testcase( jj==nTo-1 );
            break;
          }
        }
        if( jj>=nTo ){
          if( nTo>=mxChoice && rCost>=mxCost ){
#ifdef WHERETRACE_ENABLED
            if( sqlite4WhereTrace&0x4 ){
              sqlite4DebugPrintf("Skip   %s cost=%3d order=%c\n",
                  wherePathName(pFrom, iLoop, pWLoop), rCost,
                  isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
            }
#endif
            continue;
          }
          /* Add a new Path to the aTo[] set */
          if( nTo<mxChoice ){
            /* Increase the size of the aTo set by one */
            jj = nTo++;
          }else{
            /* New path replaces the prior worst to keep count below mxChoice */
            for(jj=nTo-1; aTo[jj].rCost<mxCost; jj--){ assert(jj>0); }
          }
          pTo = &aTo[jj];
#ifdef WHERETRACE_ENABLED
          if( sqlite4WhereTrace&0x4 ){
            sqlite4DebugPrintf("New    %s cost=%-3d order=%c\n",
                wherePathName(pFrom, iLoop, pWLoop), rCost,
                isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
          }
#endif
        }else{
          if( pTo->rCost<=rCost ){
#ifdef WHERETRACE_ENABLED
            if( sqlite4WhereTrace&0x4 ){
              sqlite4DebugPrintf(
                  "Skip   %s cost=%-3d order=%c",
                  wherePathName(pFrom, iLoop, pWLoop), rCost,
                  isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
              sqlite4DebugPrintf("   vs %s cost=%-3d order=%c\n",
                  wherePathName(pTo, iLoop+1, 0), pTo->rCost,
                  pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
            }
#endif
            testcase( pTo->rCost==rCost );
            continue;
          }
          testcase( pTo->rCost==rCost+1 );
          /* A new and better score for a previously created equivalent path */
#ifdef WHERETRACE_ENABLED
          if( sqlite4WhereTrace&0x4 ){
            sqlite4DebugPrintf(
                "Update %s cost=%-3d order=%c",
                wherePathName(pFrom, iLoop, pWLoop), rCost,
                isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
            sqlite4DebugPrintf("  was %s cost=%-3d order=%c\n",
                wherePathName(pTo, iLoop+1, 0), pTo->rCost,
                pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
          }
#endif
        }
        /* pWLoop is a winner.  Add it to the set of best so far */
        pTo->maskLoop = pFrom->maskLoop | pWLoop->maskSelf;
        pTo->revLoop = revMask;
        pTo->nRow = pFrom->nRow + pWLoop->nOut;
        pTo->rCost = rCost;
        pTo->isOrderedValid = isOrderedValid;
        pTo->isOrdered = isOrdered;
        memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
        pTo->aLoop[iLoop] = pWLoop;
        if( nTo>=mxChoice ){
          mxCost = aTo[0].rCost;
          for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){
            if( pTo->rCost>mxCost ) mxCost = pTo->rCost;
          }
        }
      }
    }

#ifdef WHERETRACE_ENABLED
    if( sqlite4WhereTrace>=2 ){
      sqlite4DebugPrintf("---- after round %d ----\n", iLoop);
      for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
        sqlite4DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
           wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
           pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
        if( pTo->isOrderedValid && pTo->isOrdered ){
          sqlite4DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
        }else{
          sqlite4DebugPrintf("\n");
        }
      }
    }
#endif

    /* Swap the roles of aFrom and aTo for the next generation */
    pFrom = aTo;
    aTo = aFrom;
    aFrom = pFrom;
    nFrom = nTo;
  }

  if( nFrom==0 ){
    sqlite4ErrorMsg(pParse, "no query solution");
    sqlite4DbFree(db, pSpace);
    return SQLITE4_ERROR;
  }
  
  /* Find the lowest cost path.  pFrom will be left pointing to that path */
  pFrom = aFrom;
  assert( nFrom==1 );
#if 0 /* The following is needed if nFrom is ever more than 1 */
  for(ii=1; ii<nFrom; ii++){
    if( pFrom->rCost>aFrom[ii].rCost ) pFrom = &aFrom[ii];
  }

#endif
  assert( pWInfo->nLevel==nLoop );
  /* Load the lowest cost path into pWInfo */
  for(iLoop=0; iLoop<nLoop; iLoop++){
    WhereLevel *pLevel = pWInfo->a + iLoop;
    pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop];
    pLevel->iFrom = pWLoop->iTab;
    pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
  }
  if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0
   && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
   && pWInfo->eDistinct==WHERE_DISTINCT_NOOP
   && nRowEst
  ){
    Bitmask notUsed;
    int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
                 WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], &notUsed);
    if( rc==1 ) pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
  }
  if( pFrom->isOrdered ){
    if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
    }else{
      pWInfo->bOBSat = 1;
      pWInfo->revMask = pFrom->revLoop;
    }
  }
  pWInfo->nRowOut = pFrom->nRow;

  /* Free temporary memory and return success */
  sqlite4DbFree(db, pSpace);
  return SQLITE4_OK;
}

/*
** Most queries use only a single table (they are not joins) and have
** simple == constraints against indexed fields.  This routine attempts
** to plan those simple cases using much less ceremony than the
** general-purpose query planner, and thereby yield faster sqlite4_prepare()
** times for the common case.
**
** Return non-zero on success, if this query can be handled by this
** no-frills query planner.  Return zero if this query needs the 
** general-purpose query planner.
*/
static int whereShortCut(WhereLoopBuilder *pBuilder){
  WhereInfo *pWInfo;
  struct SrcListItem *pItem;
  WhereClause *pWC;
  WhereTerm *pTerm;
  WhereLoop *pLoop;
  int iCur;
  int j;
  Table *pTab;
  Index *pIdx;

  return 0;
  
  pWInfo = pBuilder->pWInfo;
  if( pWInfo->wctrlFlags & WHERE_FORCE_TABLE ) return 0;
  assert( pWInfo->pTabList->nSrc>=1 );
  pItem = pWInfo->pTabList->a;
  pTab = pItem->pTab;
  if( IsVirtual(pTab) ) return 0;
  if( pItem->zIndex ) return 0;
  iCur = pItem->iCursor;
  pWC = &pWInfo->sWC;
  pLoop = pBuilder->pNew;
  pLoop->wsFlags = 0;
  pTerm = findTerm(pWC, iCur, -1, 0, WO_EQ, 0);
  if( pTerm ){
    assert( 0 );
    pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
    pLoop->aLTerm[0] = pTerm;
    pLoop->nLTerm = 1;
    pLoop->u.btree.nEq = 1;
    /* TUNING: Cost of a rowid lookup is 10 */
    pLoop->rRun = 33;  /* 33==whereCost(10) */
  }else{
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->onError==OE_None ) continue;
      for(j=0; j<pIdx->nColumn; j++){
        pTerm = findTerm(pWC, iCur, pIdx->aiColumn[j], 0, WO_EQ, pIdx);
        if( pTerm==0 ) break;
        whereLoopResize(pWInfo->pParse->db, pLoop, j);
        pLoop->aLTerm[j] = pTerm;
      }
      if( j!=pIdx->nColumn ) continue;
      pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
      if( (pItem->colUsed & ~columnsInIndex(pIdx))==0 ){
        pLoop->wsFlags |= WHERE_IDX_ONLY;
      }
      pLoop->nLTerm = j;
      pLoop->u.btree.nEq = j;
      pLoop->u.btree.pIndex = pIdx;
      /* TUNING: Cost of a unique index lookup is 15 */
      pLoop->rRun = 39;  /* 39==whereCost(15) */
      break;
    }
  }
  if( pLoop->wsFlags ){
    pLoop->nOut = (WhereCost)1;
    pWInfo->a[0].pWLoop = pLoop;
    pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur);
    pWInfo->a[0].iTabCur = iCur;
    pWInfo->nRowOut = 1;
    if( pWInfo->pOrderBy ) pWInfo->bOBSat =  1;
    if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
#ifdef SQLITE4_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
  }
  return 0;
}

/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite4WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
................................................................................
**
** Note that the loops might not be nested in the order in which they
** appear in the FROM clause if a different order is better able to make
** use of indices.  Note also that when the IN operator appears in
** the WHERE clause, it might result in additional nested loops for
** scanning through all values on the right-hand side of the IN.
**
** There are Btree cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite4WhereEnd() generates the code to close them.
**
** The code that sqlite4WhereBegin() generates leaves the cursors named
** in pTabList pointing at their appropriate entries.  The [...] code
** can use OP_Column and OP_Rowid opcodes on these cursors to extract
................................................................................
**        move the row2 cursor to a null row
**        goto start
**      fi
**    end
**
** ORDER BY CLAUSE PROCESSING
**
** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause
** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement
** if there is one.  If there is no ORDER BY clause or if this routine
** is called from an UPDATE or DELETE statement, then pOrderBy is NULL.









*/
WhereInfo *sqlite4WhereBegin(
  Parse *pParse,        /* The parser context */
  SrcList *pTabList,    /* FROM clause: A list of all tables to be scanned */
  Expr *pWhere,         /* The WHERE clause */
  ExprList *pOrderBy,   /* An ORDER BY clause, or NULL */
  ExprList *pResultSet, /* Result set of the query */
  u16 wctrlFlags,       /* One of the WHERE_* flags defined in sqliteInt.h */
  int iIdxCur           /* If WHERE_ONETABLE_ONLY is set, index cursor number */
){

  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  Bitmask notReady;          /* Cursors that are not yet positioned */
  WhereLoopBuilder sWLB;     /* The WhereLoop builder */
  WhereMaskSet *pMaskSet;    /* The expression mask set */


  WhereLevel *pLevel;        /* A single level in pWInfo->a[] */
  WhereLoop *pLoop;          /* Pointer to a single WhereLoop object */
  int ii;                    /* Loop counter */

  sqlite4 *db;               /* Database connection */
  int rc;                    /* Return code */

  /* src4: In SQLite3, the caller would set this flag. */
  if( pResultSet ) wctrlFlags |= WHERE_WANT_DISTINCT;

  /* Variable initialization */
  db = pParse->db;
  memset(&sWLB, 0, sizeof(sWLB));
  sWLB.pOrderBy = pOrderBy;

  /* Disable the DISTINCT optimization if SQLITE4_DistinctOpt is set via
  ** sqlite4_test_ctrl(SQLITE4_TESTCTRL_OPTIMIZATIONS,...) */
  if( OptimizationDisabled(db, SQLITE4_DistinctOpt) ){
    wctrlFlags &= ~WHERE_WANT_DISTINCT;
  }

  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask 
  */
  testcase( pTabList->nSrc==BMS );
  if( pTabList->nSrc>BMS ){
    sqlite4ErrorMsg(pParse, "at most %d tables in a join", BMS);
................................................................................
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value. A single allocation is used to store the WhereInfo
  ** struct, the contents of WhereInfo.a[], the WhereClause structure
  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
  ** some architectures. Hence the ROUND8() below.
  */

  nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
  pWInfo = sqlite4DbMallocZero(db, nByteWInfo + sizeof(WhereLoop));




  if( db->mallocFailed ){
    sqlite4DbFree(db, pWInfo);
    pWInfo = 0;
    goto whereBeginError;
  }
  pWInfo->nLevel = nTabList;
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->pOrderBy = pOrderBy;
  pWInfo->pResultSet = pResultSet;
  pWInfo->iBreak = sqlite4VdbeMakeLabel(v);

  pWInfo->wctrlFlags = wctrlFlags;
  pWInfo->savedNQueryLoop = pParse->nQueryLoop;


  pMaskSet = &pWInfo->sMaskSet;
  sWLB.pWInfo = pWInfo;
  sWLB.pWC = &pWInfo->sWC;
  sWLB.pNew = (WhereLoop*)&pWInfo->a[nTabList];
  whereLoopInit(sWLB.pNew);
#ifdef SQLITE4_DEBUG
  sWLB.pNew->cId = '*';
#endif

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  whereClauseInit(&pWInfo->sWC, pWInfo);
  sqlite4ExprCodeConstants(pParse, pWhere);
  whereSplit(&pWInfo->sWC, pWhere, TK_AND);   /* IMP: R-15842-53296 */
  sqlite4CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (nTabList==0 || sqlite4ExprIsConstantNotJoin(pWhere)) ){
    sqlite4ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE4_JUMPIFNULL);
    pWhere = 0;
  }

  /* Special case: No FROM clause
  */
  if( nTabList==0 ){
    if( pOrderBy ) pWInfo->bOBSat = 1;
    if( wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
  }

  /* Assign a bit from the bitmask to every term in the FROM clause.
  **
  ** When assigning bitmask values to FROM clause cursors, it must be
  ** the case that if X is the bitmask for the N-th FROM clause term then
  ** the bitmask for all FROM clause terms to the left of the N-th term
  ** is (X-1).   An expression from the ON clause of a LEFT JOIN can use
  ** its Expr.iRightJoinTable value to find the bitmask of the right table
  ** of the join.  Subtracting one from the right table bitmask gives a
  ** bitmask for all tables to the left of the join.  Knowing the bitmask
  ** for all tables to the left of a left join is important.  Ticket #3015.
  **





  ** Note that bitmasks are created for all pTabList->nSrc tables in
  ** pTabList, not just the first nTabList tables.  nTabList is normally
  ** equal to pTabList->nSrc but might be shortened to 1 if the
  ** WHERE_ONETABLE_ONLY flag is set.
  */

  for(ii=0; ii<pTabList->nSrc; ii++){
    createMask(pMaskSet, pTabList->a[ii].iCursor);





  }
#ifndef NDEBUG
  {
    Bitmask toTheLeft = 0;
    for(ii=0; ii<pTabList->nSrc; ii++){
      Bitmask m = getMask(pMaskSet, pTabList->a[ii].iCursor);
      assert( (m-1)==toTheLeft );
      toTheLeft |= m;
    }
  }
#endif

  /* Analyze all of the subexpressions.  Note that exprAnalyze() might
  ** add new virtual terms onto the end of the WHERE clause.  We do not
  ** want to analyze these virtual terms, so start analyzing at the end
  ** and work forward so that the added virtual terms are never processed.
  */
  exprAnalyzeAll(pTabList, &pWInfo->sWC);
  if( db->mallocFailed ){
    goto whereBeginError;
  }

  /* If the ORDER BY (or GROUP BY) clause contains references to general
  ** expressions, then we won't be able to satisfy it using indices, so
  ** go ahead and disable it now.
  */
  if( pOrderBy && (wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){
    for(ii=0; ii<pOrderBy->nExpr; ii++){
      Expr *pExpr = sqlite4ExprSkipCollate(pOrderBy->a[ii].pExpr);
      if( pExpr->op!=TK_COLUMN ){
        pWInfo->pOrderBy = pOrderBy = 0;
        break;
      }else if( pExpr->iColumn<0 ){
        break;
      }
    }







  }

  if( wctrlFlags & WHERE_WANT_DISTINCT ){
    if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
      /* The DISTINCT marking is pointless.  Ignore it. */
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;

    }else if( pOrderBy==0 ){
      /* Try to ORDER BY the result set to make distinct processing easier */
      pWInfo->wctrlFlags |= WHERE_DISTINCTBY;













      pWInfo->pOrderBy = pResultSet;
    }



  }



























































  /* Construct the WhereLoop objects */
  WHERETRACE(0xffff,("*** Optimizer Start ***\n"));
  if( nTabList!=1 || whereShortCut(&sWLB)==0 ){
    rc = whereLoopAddAll(&sWLB);
    if( rc ) goto whereBeginError;
  




    /* Display all of the WhereLoop objects if wheretrace is enabled */
#ifdef WHERETRACE_ENABLED
    if( sqlite4WhereTrace ){
      WhereLoop *p;
      int i;
      static char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
                                       "ABCDEFGHIJKLMNOPQRSTUVWYXZ";
      for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
        p->cId = zLabel[i%sizeof(zLabel)];
        whereLoopPrint(p, pTabList);
      }



    }









#endif
  


    wherePathSolver(pWInfo, 0);
    if( db->mallocFailed ) goto whereBeginError;
    if( pWInfo->pOrderBy ){
       wherePathSolver(pWInfo, pWInfo->nRowOut+1);
       if( db->mallocFailed ) goto whereBeginError;
    }
  }

  if( pWInfo->pOrderBy==0 && (db->flags & SQLITE4_ReverseOrder)!=0 ){
     pWInfo->revMask = (Bitmask)(-1);
  }





  if( pParse->nErr || NEVER(db->mallocFailed) ){
    goto whereBeginError;
  }


#ifdef WHERETRACE_ENABLED
  if( sqlite4WhereTrace ){
    int ii;
    sqlite4DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
    if( pWInfo->bOBSat ){
      sqlite4DebugPrintf(" ORDERBY=0x%llx", pWInfo->revMask);
    }
    switch( pWInfo->eDistinct ){
      case WHERE_DISTINCT_UNIQUE: {
        sqlite4DebugPrintf("  DISTINCT=unique");
        break;
      }



































      case WHERE_DISTINCT_ORDERED: {
        sqlite4DebugPrintf("  DISTINCT=ordered");
        break;
      }
      case WHERE_DISTINCT_UNORDERED: {
        sqlite4DebugPrintf("  DISTINCT=unordered");
        break;
      }
    }








    sqlite4DebugPrintf("\n");
    for(ii=0; ii<pWInfo->nLevel; ii++){
      whereLoopPrint(pWInfo->a[ii].pWLoop, pTabList);
    }



  }


#endif
  /* Attempt to omit tables from the join that do not effect the result */
  if( pWInfo->nLevel>=2
   && pResultSet!=0
   && OptimizationEnabled(db, SQLITE4_OmitNoopJoin)
  ){
    Bitmask tabUsed = exprListTableUsage(pMaskSet, pResultSet);
    if( pOrderBy ) tabUsed |= exprListTableUsage(pMaskSet, pOrderBy);
    while( pWInfo->nLevel>=2 ){
      WhereTerm *pTerm, *pEnd;
      pLoop = pWInfo->a[pWInfo->nLevel-1].pWLoop;
      if( (pWInfo->pTabList->a[pLoop->iTab].jointype & JT_LEFT)==0 ) break;
      if( (wctrlFlags & WHERE_WANT_DISTINCT)==0
       && (pLoop->wsFlags & WHERE_ONEROW)==0





      ){
        break;
      }




      if( (tabUsed & pLoop->maskSelf)!=0 ) break;
      pEnd = sWLB.pWC->a + sWLB.pWC->nTerm;
      for(pTerm=sWLB.pWC->a; pTerm<pEnd; pTerm++){
        if( (pTerm->prereqAll & pLoop->maskSelf)!=0
         && !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
        ){
          break;
        }
      }





      if( pTerm<pEnd ) break;
      WHERETRACE(0xffff, ("-> drop loop %c not used\n", pLoop->cId));
      pWInfo->nLevel--;
      nTabList--;









    }
  }

  WHERETRACE(0xffff,("*** Optimizer Finished ***\n"));










  pWInfo->pParse->nQueryLoop += pWInfo->nRowOut;

  /* If the caller is an UPDATE or DELETE statement that is requesting
  ** to use a one-pass algorithm, determine if this is appropriate.
  ** The one-pass algorithm only works if the WHERE clause constraints
  ** the statement to update a single row.
  */
  assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
  if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 
   && (pWInfo->a[0].pWLoop->wsFlags & WHERE_ONEROW)!=0 ){
    pWInfo->okOnePass = 1;
    pWInfo->a[0].pWLoop->wsFlags &= ~WHERE_IDX_ONLY;
  }

  /* Open all tables in the pTabList and any indices selected for
  ** searching those tables.
  */

  notReady = ~(Bitmask)0;

  for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
    Table *pTab;     /* Table to open */
    int iDb;         /* Index of database containing table/index */
    struct SrcListItem *pTabItem;

    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;


    iDb = sqlite4SchemaToIndex(db, pTab->pSchema);
    pLoop = pLevel->pWLoop;
    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
      /* Do nothing */
    }else
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
      const char *pVTab = (const char *)sqlite4GetVTable(db, pTab);
      int iCur = pTabItem->iCursor;
      sqlite4VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
    }else if( IsVirtual(pTab) ){
      /* noop */
    }else
#endif
    if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
      sqlite4OpenPrimaryKey(pParse, pTabItem->iCursor, iDb, pTab, op);
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS-1 );
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS );
#if 0
      if( !pWInfo->okOnePass && pTab->nCol<BMS ){
        Bitmask b = pTabItem->colUsed;
        int n = 0;
        for(; b; b=b>>1, n++){}
        sqlite4VdbeChangeP4(v, sqlite4VdbeCurrentAddr(v)-1, 
                            SQLITE4_INT_TO_PTR(n), P4_INT32);
        assert( n<=pTab->nCol );
      }
#endif
    }
#if 0
    else{
      sqlite4TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
    }
#endif
#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX

    if( (pLoop->wsFlags & WHERE_AUTO_INDEX)!=0 ){
      constructAutomaticIndex(pParse, &pWInfo->sWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( pLoop->wsFlags & WHERE_INDEXED ){
      Index *pIx = pLoop->u.btree.pIndex;
      if( pIx->eIndexType==SQLITE4_INDEX_PRIMARYKEY ){
        pLevel->iIdxCur = pTabItem->iCursor;
      }
      else if( pIx->eIndexType!=SQLITE4_INDEX_FTS5 ){
        KeyInfo *pKey = sqlite4IndexKeyinfo(pParse, pIx);
        /* FIXME:  As an optimization use pTabItem->iCursor if WHERE_IDX_ONLY */
        int iIndexCur = pLevel->iIdxCur = iIdxCur ? iIdxCur : pParse->nTab++;
        assert( pIx->pSchema==pTab->pSchema );
        assert( iIndexCur>=0 );
        sqlite4VdbeAddOp4(v, OP_OpenRead, iIndexCur, pIx->tnum, iDb,
            (char*)pKey, P4_KEYINFO_HANDOFF);
        VdbeComment((v, "%s", pIx->zName));
      }
    }
    sqlite4CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite4VdbeCurrentAddr(v);
  if( db->mallocFailed ) goto whereBeginError;

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
  ** program.
  */
  notReady = ~(Bitmask)0;
  for(ii=0; ii<nTabList; ii++){
    pLevel = &pWInfo->a[ii];
    explainOneScan(pParse, pTabList, pLevel, ii, pLevel->iFrom, wctrlFlags);
    notReady = codeOneLoopStart(pWInfo, ii, notReady);
    pWInfo->iContinue = pLevel->addrCont;
  }

  /* Done. */














































  return pWInfo;

  /* Jump here if malloc fails */
whereBeginError:
  if( pWInfo ){
    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
    whereInfoFree(db, pWInfo);
................................................................................
** sqlite4WhereBegin() for additional information.
*/
void sqlite4WhereEnd(WhereInfo *pWInfo){
  Parse *pParse = pWInfo->pParse;
  Vdbe *v = pParse->pVdbe;
  int i;
  WhereLevel *pLevel;
  WhereLoop *pLoop;
  SrcList *pTabList = pWInfo->pTabList;
  sqlite4 *db = pParse->db;

  /* Generate loop termination code.
  */
  sqlite4ExprCacheClear(pParse);
  for(i=pWInfo->nLevel-1; i>=0; i--){
    pLevel = &pWInfo->a[i];
    pLoop = pLevel->pWLoop;
    sqlite4VdbeResolveLabel(v, pLevel->addrCont);
    if( pLevel->op!=OP_Noop ){
      sqlite4VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
      sqlite4VdbeChangeP5(v, pLevel->p5);
    }
    if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite4VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        sqlite4VdbeJumpHere(v, pIn->addrInTop+1);
        sqlite4VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
        sqlite4VdbeJumpHere(v, pIn->addrInTop-1);
      }
      sqlite4DbFree(db, pLevel->u.in.aInLoop);
    }
    sqlite4VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqlite4VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
      assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
           || (pLoop->wsFlags & WHERE_INDEXED)!=0 );
      if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
      }
      if( pLoop->wsFlags & WHERE_INDEXED ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
      }
      if( pLevel->op==OP_Return ){
        sqlite4VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
      }else{
        sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
      }
................................................................................
  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite4VdbeResolveLabel(v, pWInfo->iBreak);

  /* Close all of the cursors that were opened by sqlite4WhereBegin.
  */
  assert( pWInfo->nLevel<=pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
    struct SrcListItem *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    pLoop = pLevel->pWLoop;
    if( (pTab->tabFlags & TF_Ephemeral)==0
     && pTab->pSelect==0
     && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
    ){
      int ws = pLoop->wsFlags;
      if( !pWInfo->okOnePass && (ws & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
      }
      if( (ws & WHERE_INDEXED)!=0 && (ws & (WHERE_IPK|WHERE_AUTO_INDEX))==0 ){
        if( pLevel->iIdxCur!=pTabItem->iCursor ){
          sqlite4VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
        }
      }
    }

    /* If this scan uses an index, make VDBE code substitutions to read data
    ** from the index instead of from the table where possible.  In some cases
    ** this optimization prevents the table from ever being read, which can
    ** yield a significant performance boost.


    ** 
    ** Calls to the code generator in between sqlite4WhereBegin and
    ** sqlite4WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( (pLoop->wsFlags & WHERE_AUTO_INDEX) && !db->mallocFailed ){
      int k, j, last;
      VdbeOp *pOp;

      Index *pIdx = pLoop->u.btree.pIndex;



      pOp = sqlite4VdbeGetOp(v, pWInfo->iTop);
      last = sqlite4VdbeCurrentAddr(v);


      for(k=pWInfo->iTop; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          for(j=0; j<pIdx->nColumn; j++){
            if( pOp->p2==pIdx->aiColumn[j] ){
              pOp->p2 = j;
              pOp->p1 = pLevel->iIdxCur;
              break;
            }

          }


          assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 || j<pIdx->nColumn );
        }else if( pOp->opcode==OP_Rowid ){










          pOp->p1 = pLevel->iIdxCur;
          pOp->opcode = OP_IdxRowid;
        }

      }
    }
  }

  /* Final cleanup
  */
  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
  whereInfoFree(db, pWInfo);
  return;
}

Changes to test/analyze4.test.

34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
    INSERT INTO t1 SELECT a+32, b FROM t1;
    INSERT INTO t1 SELECT a+64, b FROM t1;
    ANALYZE;
  }

  # Should choose the t1a index since it is more specific than t1b.
  db eval {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=5 AND b IS NULL}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}

# Verify that the t1b index shows that it does not narrow down the
# search any at all.
#
do_test analyze4-1.1 {
  db eval {
    SELECT idx, stat FROM sqlite_stat1 WHERE tbl='t1' ORDER BY idx;







|







34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
    INSERT INTO t1 SELECT a+32, b FROM t1;
    INSERT INTO t1 SELECT a+64, b FROM t1;
    ANALYZE;
  }

  # Should choose the t1a index since it is more specific than t1b.
  db eval {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=5 AND b IS NULL}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}}

# Verify that the t1b index shows that it does not narrow down the
# search any at all.
#
do_test analyze4-1.1 {
  db eval {
    SELECT idx, stat FROM sqlite_stat1 WHERE tbl='t1' ORDER BY idx;

Changes to test/between.test.

44
45
46
47
48
49
50
51
52
53
54
55
56
57
58










59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
...
103
104
105
106
107
108
109
110
111
112
113
    CREATE INDEX i1zyx ON t1(z,y,x);
    COMMIT;
  }
} {}

# This procedure executes the SQL.  Then it appends to the result the
# "sort" or "nosort" keyword depending on whether or not any sorting
# is done.  Then it appends the ::sqlite_query_plan variable.
#
proc queryplan {sql} {
  set ::sqlite_sort_count 0
  set data [execsql $sql]
  if {$::sqlite_sort_count} {set x sort} {set x nosort}
  lappend data $x
  return [concat $data $::sqlite_query_plan]










}

do_test between-1.1.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.1.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.2.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.2.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.3.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.3.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.4 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.5.1 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.2 {
  queryplan {
................................................................................
    SELECT * FROM t1 WHERE 26 BETWEEN +y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.3 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND +z ORDER BY +w
  }
} {4 2 25 27 sort t1 {}}


finish_test







|






|
>
>
>
>
>
>
>
>
>
>











|









|









|




|







 







|



44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
...
113
114
115
116
117
118
119
120
121
122
123
    CREATE INDEX i1zyx ON t1(z,y,x);
    COMMIT;
  }
} {}

# This procedure executes the SQL.  Then it appends to the result the
# "sort" or "nosort" keyword depending on whether or not any sorting
# is done.  Then it appends the names of the table and index used.
#
proc queryplan {sql} {
  set ::sqlite_sort_count 0
  set data [execsql $sql]
  if {$::sqlite_sort_count} {set x sort} {set x nosort}
  lappend data $x
  set eqp [execsql "EXPLAIN QUERY PLAN $sql"]
  # puts eqp=$eqp
  foreach {a b c x} $eqp {
    if {[regexp { TABLE (\w+ AS )?(\w+) USING.* INDEX (\w+)\y} \
        $x all as tab idx]} {
      lappend data $tab $idx
    } elseif {[regexp { TABLE (\w+ AS )?(\w+)\y} $x all as tab]} {
      lappend data $tab *
    }
  }
  return $data   
}

do_test between-1.1.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.1.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.2.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.2.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.3.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.3.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.4 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.5.1 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.2 {
  queryplan {
................................................................................
    SELECT * FROM t1 WHERE 26 BETWEEN +y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.3 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND +z ORDER BY +w
  }
} {4 2 25 27 sort t1 t1}


finish_test

Changes to test/collate4.test.

85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
...
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
...
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
...
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
...
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
  cksort {SELECT b FROM collate4t1 ORDER BY b}
} {{} A B a b nosort}
do_test collate4-1.1.5 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.6 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE NOCASE}
} {{} a A b B sort}

do_test collate4-1.1.7 {
  execsql {
    CREATE TABLE collate4t2(
      a PRIMARY KEY COLLATE NOCASE, 
      b UNIQUE COLLATE TEXT
    );
................................................................................
    INSERT INTO collate4t4 VALUES( 'A', 'A' );
    CREATE INDEX collate4i3 ON collate4t4(a COLLATE TEXT);
    CREATE INDEX collate4i4 ON collate4t4(b COLLATE NOCASE);
  }
} {}
do_test collate4-1.1.22 {
  cksort {SELECT a FROM collate4t4 ORDER BY a}
} {{} a A b B sort}
do_test collate4-1.1.23 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE NOCASE}
} {{} a A b B sort}
do_test collate4-1.1.24 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.25 {
  cksort {SELECT b FROM collate4t4 ORDER BY b}
} {{} A B a b sort}
do_test collate4-1.1.26 {
................................................................................
  cksort {SELECT a FROM collate4t1 ORDER BY a COLLATE text}
} {{} A B a b sort}
do_test collate4-1.2.4 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b}
} {{} A a B b nosort}
do_test collate4-1.2.5 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE nocase}
} {{} a A b B sort}
do_test collate4-1.2.6 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE text}
} {{} A a B b nosort}

do_test collate4-1.2.7 {
  execsql {
    CREATE TABLE collate4t2(
................................................................................
    INSERT INTO collate4t3 VALUES( 'B', 'B' );
    INSERT INTO collate4t3 VALUES( 'A', 'A' );
    CREATE INDEX collate4i2 ON collate4t3(a COLLATE TEXT, b COLLATE NOCASE);
  }
} {}
do_test collate4-1.2.15 {
  cksort {SELECT a FROM collate4t3 ORDER BY a}
} {{} a A b B sort}
do_test collate4-1.2.16 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE nocase}
} {{} a A b B sort}
do_test collate4-1.2.17 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text}
} {{} A B a b nosort}
do_test collate4-1.2.18 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text, b}
} {{} A B a b sort}
do_test collate4-1.2.19 {
................................................................................
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a COLLATE NUMERIC);
  }
  count {
    SELECT min(a) FROM collate4t1;
  }
} {10 5}
do_test collate4-4.6 {
  count {
    SELECT max(a) FROM collate4t1;
  }
} {20 5}
do_test collate4-4.7 {
  execsql {
    DROP TABLE collate4t1;
  }
} {}

# Also test the scalar min() and max() functions.







|







 







|


|







 







|







 







|


|







 







|




|







85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
...
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
...
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
...
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
...
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
  cksort {SELECT b FROM collate4t1 ORDER BY b}
} {{} A B a b nosort}
do_test collate4-1.1.5 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.6 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE NOCASE}
} {{} A a B b sort}

do_test collate4-1.1.7 {
  execsql {
    CREATE TABLE collate4t2(
      a PRIMARY KEY COLLATE NOCASE, 
      b UNIQUE COLLATE TEXT
    );
................................................................................
    INSERT INTO collate4t4 VALUES( 'A', 'A' );
    CREATE INDEX collate4i3 ON collate4t4(a COLLATE TEXT);
    CREATE INDEX collate4i4 ON collate4t4(b COLLATE NOCASE);
  }
} {}
do_test collate4-1.1.22 {
  cksort {SELECT a FROM collate4t4 ORDER BY a}
} {{} A a B b sort}
do_test collate4-1.1.23 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE NOCASE}
} {{} A a B b sort}
do_test collate4-1.1.24 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.25 {
  cksort {SELECT b FROM collate4t4 ORDER BY b}
} {{} A B a b sort}
do_test collate4-1.1.26 {
................................................................................
  cksort {SELECT a FROM collate4t1 ORDER BY a COLLATE text}
} {{} A B a b sort}
do_test collate4-1.2.4 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b}
} {{} A a B b nosort}
do_test collate4-1.2.5 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE nocase}
} {{} A a B b sort}
do_test collate4-1.2.6 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE text}
} {{} A a B b nosort}

do_test collate4-1.2.7 {
  execsql {
    CREATE TABLE collate4t2(
................................................................................
    INSERT INTO collate4t3 VALUES( 'B', 'B' );
    INSERT INTO collate4t3 VALUES( 'A', 'A' );
    CREATE INDEX collate4i2 ON collate4t3(a COLLATE TEXT, b COLLATE NOCASE);
  }
} {}
do_test collate4-1.2.15 {
  cksort {SELECT a FROM collate4t3 ORDER BY a}
} {{} A a B b sort}
do_test collate4-1.2.16 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE nocase}
} {{} A a B b sort}
do_test collate4-1.2.17 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text}
} {{} A B a b nosort}
do_test collate4-1.2.18 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text, b}
} {{} A B a b sort}
do_test collate4-1.2.19 {
................................................................................
  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a COLLATE NUMERIC);
  }
  count {
    SELECT min(a) FROM collate4t1;
  }
} {10 9}
do_test collate4-4.6 {
  count {
    SELECT max(a) FROM collate4t1;
  }
} {20 9}
do_test collate4-4.7 {
  execsql {
    DROP TABLE collate4t1;
  }
} {}

# Also test the scalar min() and max() functions.

Changes to test/descidx3.test.

107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
} {9 7 6 8 3 4 2 5}

ifcapable subquery {
  # If the subquery capability is not compiled in to the binary, then
  # the IN(...) operator is not available. Hence these tests cannot be 
  # run.
  do_test descidx3-4.1 {
    execsql {
      UPDATE t1 SET a=2 WHERE i<6;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }
  } {8 6 2 4 3}
  do_test descidx3-4.2 {
    execsql {
      UPDATE t1 SET a=1;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }
  } {2 4 3 8 6}
  do_test descidx3-4.3 {







|


|
|







107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
} {9 7 6 8 3 4 2 5}

ifcapable subquery {
  # If the subquery capability is not compiled in to the binary, then
  # the IN(...) operator is not available. Hence these tests cannot be 
  # run.
  do_test descidx3-4.1 {
    lsort [execsql {
      UPDATE t1 SET a=2 WHERE i<6;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }]
  } {2 3 4 6 8}
  do_test descidx3-4.2 {
    execsql {
      UPDATE t1 SET a=1;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }
  } {2 4 3 8 6}
  do_test descidx3-4.3 {

Changes to test/e_createtable.test.

1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
#
do_execsql_test 4.10.0 {
  CREATE TABLE t1(a, b PRIMARY KEY);
  CREATE TABLE t2(a, b, c, UNIQUE(b, c));
}
do_createtable_tests 4.10 {
  1    "EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b = 5" 
       {0 0 0 {SEARCH TABLE t1 USING PRIMARY KEY (b=?) (~1 rows)}}

  2    "EXPLAIN QUERY PLAN SELECT * FROM t2 ORDER BY b, c"
       {0 0 0 {SCAN TABLE t2 USING INDEX sqlite_t2_unique1 (~1000000 rows)}}

  3    "EXPLAIN QUERY PLAN SELECT * FROM t2 WHERE b=10 AND c>10"
       {0 0 0 {SEARCH TABLE t2 USING INDEX sqlite_t2_unique1 (b=? AND c>?) (~2 rows)}}
}

# EVIDENCE-OF: R-45493-35653 A CHECK constraint may be attached to a
# column definition or specified as a table constraint. In practice it
# makes no difference.
#
#   All the tests that deal with CHECK constraints below (4.11.* and 







|


|


|







1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
#
do_execsql_test 4.10.0 {
  CREATE TABLE t1(a, b PRIMARY KEY);
  CREATE TABLE t2(a, b, c, UNIQUE(b, c));
}
do_createtable_tests 4.10 {
  1    "EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b = 5" 
       {0 0 0 {SEARCH TABLE t1 USING INDEX t1 (b=?)}}

  2    "EXPLAIN QUERY PLAN SELECT * FROM t2 ORDER BY b, c"
       {0 0 0 {SCAN TABLE t2 USING INDEX sqlite_t2_unique1}}

  3    "EXPLAIN QUERY PLAN SELECT * FROM t2 WHERE b=10 AND c>10"
       {0 0 0 {SEARCH TABLE t2 USING INDEX sqlite_t2_unique1 (b=? AND c>?)}}
}

# EVIDENCE-OF: R-45493-35653 A CHECK constraint may be attached to a
# column definition or specified as a table constraint. In practice it
# makes no difference.
#
#   All the tests that deal with CHECK constraints below (4.11.* and 

Changes to test/e_fkey.test.

961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
....
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
  }
} {}
do_execsql_test e_fkey-25.2 {
  PRAGMA foreign_keys = OFF;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
  EXPLAIN QUERY PLAN SELECT rowid FROM track WHERE trackartist = ?;
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SCAN TABLE track (~100000 rows)}
}
do_execsql_test e_fkey-25.3 {
  PRAGMA foreign_keys = ON;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SCAN TABLE track (~100000 rows)}
}
do_test e_fkey-25.4 {
  execsql {
    INSERT INTO artist VALUES(5, 'artist 5');
    INSERT INTO artist VALUES(6, 'artist 6');
    INSERT INTO artist VALUES(7, 'artist 7');
    INSERT INTO track VALUES(1, 'track 1', 5);
................................................................................
} {}
do_test e_fkey-27.2 {
  eqp { INSERT INTO artist VALUES(?, ?) }
} {}
do_execsql_test e_fkey-27.3 {
  EXPLAIN QUERY PLAN UPDATE artist SET artistid = ?, artistname = ?
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?) (~10 rows)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?) (~10 rows)}
}
do_execsql_test e_fkey-27.4 {
  EXPLAIN QUERY PLAN DELETE FROM artist
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?) (~10 rows)}
}


###########################################################################
### SECTION 4.1: Composite Foreign Key Constraints
###########################################################################








|
|





|
|







 







|
|
|




|
|







961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
....
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
  }
} {}
do_execsql_test e_fkey-25.2 {
  PRAGMA foreign_keys = OFF;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
  EXPLAIN QUERY PLAN SELECT rowid FROM track WHERE trackartist = ?;
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist} 
  0 0 0 {SCAN TABLE track USING INDEX track}
}
do_execsql_test e_fkey-25.3 {
  PRAGMA foreign_keys = ON;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist}
  0 0 0 {SCAN TABLE track USING INDEX track}
}
do_test e_fkey-25.4 {
  execsql {
    INSERT INTO artist VALUES(5, 'artist 5');
    INSERT INTO artist VALUES(6, 'artist 6');
    INSERT INTO artist VALUES(7, 'artist 7');
    INSERT INTO track VALUES(1, 'track 1', 5);
................................................................................
} {}
do_test e_fkey-27.2 {
  eqp { INSERT INTO artist VALUES(?, ?) }
} {}
do_execsql_test e_fkey-27.3 {
  EXPLAIN QUERY PLAN UPDATE artist SET artistid = ?, artistname = ?
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist}
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?)}
}
do_execsql_test e_fkey-27.4 {
  EXPLAIN QUERY PLAN DELETE FROM artist
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?)}
}


###########################################################################
### SECTION 4.1: Composite Foreign Key Constraints
###########################################################################

Changes to test/like.test.

185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
...
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
...
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
...
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
# is performed.
#
do_test like-3.1 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {ABC {ABC abc xyz} abc abcd sort t1 *}
do_test like-3.2 {
  set sqlite_like_count
} {12}

# With an index on t1.x and case sensitivity on, optimize completely.
#
do_test like-3.3 {
................................................................................
  db eval {
    PRAGMA case_sensitive_like=on;
    DROP INDEX i1;
  }
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {abc abcd sort t1 *}
do_test like-3.16 {
  set sqlite_like_count
} 12

# No GLOB optimization without an index.
#
do_test like-3.17 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x GLOB 'abc*' ORDER BY 1;
  }
} {abc abcd sort t1 *}
do_test like-3.18 {
  set sqlite_like_count
} 12

# GLOB is optimized regardless of the case_sensitive_like setting.
#
do_test like-3.19 {
................................................................................
  }
} {12}
do_test like-11.1 {
  db eval {PRAGMA case_sensitive_like=OFF;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd ABC ABCD nosort t11 *}
do_test like-11.2 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 *}
do_test like-11.3 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    CREATE INDEX t11b ON t11(b);
  }
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY +a;
................................................................................
  }
} {abc abcd ABC ABCD sort t11 t11b}
do_test like-11.4 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 *}
do_test like-11.5 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    DROP INDEX t11b;
    CREATE INDEX t11bnc ON t11(b COLLATE nocase);
  }
  queryplan {







|







 







|











|







 







|





|







 







|







185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
...
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
...
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
...
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
# is performed.
#
do_test like-3.1 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {ABC {ABC abc xyz} abc abcd sort t1 t1}
do_test like-3.2 {
  set sqlite_like_count
} {12}

# With an index on t1.x and case sensitivity on, optimize completely.
#
do_test like-3.3 {
................................................................................
  db eval {
    PRAGMA case_sensitive_like=on;
    DROP INDEX i1;
  }
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {abc abcd sort t1 t1}
do_test like-3.16 {
  set sqlite_like_count
} 12

# No GLOB optimization without an index.
#
do_test like-3.17 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x GLOB 'abc*' ORDER BY 1;
  }
} {abc abcd sort t1 t1}
do_test like-3.18 {
  set sqlite_like_count
} 12

# GLOB is optimized regardless of the case_sensitive_like setting.
#
do_test like-3.19 {
................................................................................
  }
} {12}
do_test like-11.1 {
  db eval {PRAGMA case_sensitive_like=OFF;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd ABC ABCD nosort t11 t11}
do_test like-11.2 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 t11}
do_test like-11.3 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    CREATE INDEX t11b ON t11(b);
  }
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY +a;
................................................................................
  }
} {abc abcd ABC ABCD sort t11 t11b}
do_test like-11.4 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 t11}
do_test like-11.5 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    DROP INDEX t11b;
    CREATE INDEX t11bnc ON t11(b COLLATE nocase);
  }
  queryplan {

Changes to test/permutations.test.

127
128
129
130
131
132
133

134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
#   src4
#   veryquick
#   quick
#   full
#
lappend ::testsuitelist xxx


test_suite "src4" -prefix "" -description {
} -files {
  simple.test simple2.test
  lsm1.test lsm2.test lsm3.test lsm4.test lsm5.test
  csr1.test
  ckpt1.test
  mc1.test
  fts5expr1.test fts5query1.test fts5rnd1.test fts5create.test
  fts5snippet.test

  alter.test alter3.test alter4.test
  analyze.test analyze3.test analyze4.test analyze5.test 
  analyze6.test analyze7.test analyze8.test
  auth.test auth2.test auth3.test auth4.test
  aggerror.test
  attach.test attach3.test attach4.test







>







<
<







127
128
129
130
131
132
133
134
135
136
137
138
139
140
141


142
143
144
145
146
147
148
#   src4
#   veryquick
#   quick
#   full
#
lappend ::testsuitelist xxx

# fts5expr1.test fts5query1.test fts5rnd1.test fts5create.test fts5snippet.test
test_suite "src4" -prefix "" -description {
} -files {
  simple.test simple2.test
  lsm1.test lsm2.test lsm3.test lsm4.test lsm5.test
  csr1.test
  ckpt1.test
  mc1.test



  alter.test alter3.test alter4.test
  analyze.test analyze3.test analyze4.test analyze5.test 
  analyze6.test analyze7.test analyze8.test
  auth.test auth2.test auth3.test auth4.test
  aggerror.test
  attach.test attach3.test attach4.test

Changes to test/simple.test.

693
694
695
696
697
698
699



700


701
702
703
704
705
706
707
....
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
....
1611
1612
1613
1614
1615
1616
1617







1618







































1619
1620
1621
do_execsql_test 38.2 {
  CREATE VIEW v1 AS SELECT a, b FROM t1;
  CREATE TRIGGER tr1 INSTEAD OF DELETE ON v1 BEGIN
    INSERT INTO log VALUES(old.b, old.a);
  END;
}
do_execsql_test 38.3 {



  DELETE FROM v1 WHERE a = 3;


  SELECT * FROM log;
} {4 3}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 39.1 {
  CREATE TABLE t1(a PRIMARY KEY, b);
................................................................................
  CREATE INDEX joinme_id_int_idx on joinme(id_int);
}

do_catchsql_test 70.2 {
  select * from maintable as m inner join
    joinme as j indexed by joinme_id_text_idx
    on ( m.id  = j.id_int)
} {1 {cannot use index: joinme_id_text_idx}}

do_catchsql_test 70.3 {
  select * from maintable, joinme INDEXED by joinme_id_text_idx
} {1 {cannot use index: joinme_id_text_idx}}

#-------------------------------------------------------------------------
# This is testing that the "phantom" runs feature works.
#
# UPDATE: Said feature was dropped early in development. But the test 
# remains valid.
reset_db
................................................................................
  INSERT INTO t1(x,y) VALUES(2,CAST(x'02' AS TEXT));
  CREATE TABLE t3(x INT, y COLLATE NOCASE);
  INSERT INTO t3 SELECT x, 'abc' || y || 'xyz' FROM t1;
  CREATE INDEX i3 ON t3(y);
  SELECT x FROM t3 WHERE y LIKE 'abcX%';
} {}

















































finish_test








>
>
>

>
>







 







|



|







 







>
>
>
>
>
>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>



693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
....
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
....
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
do_execsql_test 38.2 {
  CREATE VIEW v1 AS SELECT a, b FROM t1;
  CREATE TRIGGER tr1 INSTEAD OF DELETE ON v1 BEGIN
    INSERT INTO log VALUES(old.b, old.a);
  END;
}
do_execsql_test 38.3 {
  SELECT * FROM v1;
} {3 4}
do_execsql_test 38.4 {
  DELETE FROM v1 WHERE a = 3;
} 
do_execsql_test 38.5 {
  SELECT * FROM log;
} {4 3}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 39.1 {
  CREATE TABLE t1(a PRIMARY KEY, b);
................................................................................
  CREATE INDEX joinme_id_int_idx on joinme(id_int);
}

do_catchsql_test 70.2 {
  select * from maintable as m inner join
    joinme as j indexed by joinme_id_text_idx
    on ( m.id  = j.id_int)
} {1 {no query solution}}

do_catchsql_test 70.3 {
  select * from maintable, joinme INDEXED by joinme_id_text_idx
} {1 {no query solution}}

#-------------------------------------------------------------------------
# This is testing that the "phantom" runs feature works.
#
# UPDATE: Said feature was dropped early in development. But the test 
# remains valid.
reset_db
................................................................................
  INSERT INTO t1(x,y) VALUES(2,CAST(x'02' AS TEXT));
  CREATE TABLE t3(x INT, y COLLATE NOCASE);
  INSERT INTO t3 SELECT x, 'abc' || y || 'xyz' FROM t1;
  CREATE INDEX i3 ON t3(y);
  SELECT x FROM t3 WHERE y LIKE 'abcX%';
} {}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 86.0 { 
  SELECT * FROM sqlite_master;
} {}
do_execsql_test 86.1 { 
  CREATE TABLE t1(a PRIMARY KEY, b);
}
do_execsql_test 86.2 { 
  INSERT INTO t1 VALUES(1, 'one');
}
do_execsql_test 86.3 { 
  SELECT * FROM t1;
} {1 one}
do_execsql_test 86.4 { 
  SELECT * FROM t1 WHERE a = 1;
} {1 one}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 87.1 {
  CREATE TABLE t6(a INTEGER PRIMARY KEY, b TEXT);
  CREATE INDEX t6i1 ON t6(b);
} {}
do_eqp_test 87.2 {
  SELECT * FROM t6 ORDER BY b, a;
} {0 0 0 {SCAN TABLE t6 USING INDEX t6i1}}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 88.1 {
  CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT);
  CREATE UNIQUE INDEX t8i ON t8(b);
}
do_eqp_test 88.2 {
  SELECT * FROM t8 x ORDER BY x.b, x.a, x.b||x.a
} {0 0 0 {SCAN TABLE t8 AS x USING INDEX t8i}}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 89.1 {
  CREATE TABLE t1(a COLLATE NOCASE);
  CREATE INDEX i1 ON t1(a);
}
do_eqp_test 89.2 {
  SELECT * FROM t1 ORDER BY a;
} {0 0 0 {SCAN TABLE t1 USING INDEX i1}}

finish_test

Changes to test/subquery.test.

237
238
239
240
241
242
243
244
245



246
247
248
249
250
251
252
...
326
327
328
329
330
331
332

333
334
335
336
337
338
339
340
341
342
343
344
345
346
  execsql {
    CREATE INDEX t4i ON t4(x);
    SELECT * FROM t4 WHERE x IN (SELECT a FROM t3);
  }
} {10.0}
do_test subquery-2.5.3.2 {
  # Verify that the t4i index was not used in the previous query
  set ::sqlite_query_plan
} {t4 {}}



do_test subquery-2.5.4 {
  execsql {
    DROP TABLE t3;
    DROP TABLE t4;
  }
} {}

................................................................................
  }
} {1 one 2 two}
do_test subquery-3.3.5 {
  execsql {
    SELECT a, (SELECT count(*) FROM t2 WHERE a=c) FROM t1;
  }
} {1 1 2 1}


#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite4_reset().
#
# One problem was that VDBE memory cells were not being initialised
# to NULL on the second and subsequent executions.
#
do_test subquery-4.1.1 {
  execsql {
    SELECT (SELECT a FROM t1);
  }
} {1}







|
|
>
>
>







 







>






|







237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
...
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
  execsql {
    CREATE INDEX t4i ON t4(x);
    SELECT * FROM t4 WHERE x IN (SELECT a FROM t3);
  }
} {10.0}
do_test subquery-2.5.3.2 {
  # Verify that the t4i index was not used in the previous query
  execsql {
    EXPLAIN QUERY PLAN
    SELECT * FROM t4 WHERE x IN (SELECT a FROM t3);
  }
} {/SCAN TABLE t4 /}
do_test subquery-2.5.4 {
  execsql {
    DROP TABLE t3;
    DROP TABLE t4;
  }
} {}

................................................................................
  }
} {1 one 2 two}
do_test subquery-3.3.5 {
  execsql {
    SELECT a, (SELECT count(*) FROM t2 WHERE a=c) FROM t1;
  }
} {1 1 2 1}


#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite4_reset().
#
# One problem was that VDBE memory cells were not being initialized
# to NULL on the second and subsequent executions.
#
do_test subquery-4.1.1 {
  execsql {
    SELECT (SELECT a FROM t1);
  }
} {1}

Changes to test/test_main.c.

1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
....
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
....
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
....
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
  Tcl_Interp *interp;
  Tcl_Obj *pNeeded;
  Tcl_Obj *pDel;
};
typedef struct TestNeededX TestNeededX;

static void testCollationNeeded(void *pCtx, sqlite4 *db, const char *zReq){
  TestNeededX *p = (TestCollationX *)pCtx;
  Tcl_Obj *pScript;
  int rc;

  pScript = Tcl_DuplicateObj(p->pNeeded);
  Tcl_IncrRefCount(pScript);
  Tcl_ListObjAppendElement(0, pScript, Tcl_NewStringObj(zReq, -1));
  rc = Tcl_EvalObjEx(p->interp, pScript, TCL_EVAL_DIRECT|TCL_EVAL_GLOBAL);
................................................................................
  sqlite4_stmt *pStmt;
  int col;
  Tcl_Obj *pRet;
  const void *zName16;
  const void *(*xFunc)(sqlite4_stmt*, int, int*);
  int dummy;

  xFunc = (const void *(*)(sqlite4_stmt*, int))clientData;
  if( objc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"",
       Tcl_GetString(objv[0]), " STMT column", 0);
    return TCL_ERROR;
  }

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
................................................................................
  extern int sqlite4_os_type;
#endif
#ifdef SQLITE4_DEBUG
  extern int sqlite4WhereTrace;
  extern int sqlite4OSTrace;
#endif
#ifdef SQLITE4_TEST
  extern char sqlite4_query_plan[];
  static char *query_plan = sqlite4_query_plan;
#ifdef SQLITE4_ENABLE_FTS3
  extern int sqlite4_fts3_enable_parentheses;
#endif
#endif

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
................................................................................
#endif
  Tcl_LinkVar(interp, "sqlite4_xferopt_count",
      (char*)&sqlite4_xferopt_count, TCL_LINK_INT);
#if SQLITE4_OS_WIN
  Tcl_LinkVar(interp, "sqlite_os_type",
      (char*)&sqlite4_os_type, TCL_LINK_INT);
#endif
#ifdef SQLITE4_TEST
  Tcl_LinkVar(interp, "sqlite_query_plan",
      (char*)&query_plan, TCL_LINK_STRING|TCL_LINK_READ_ONLY);
#endif
#ifdef SQLITE4_DEBUG
  Tcl_LinkVar(interp, "sqlite_where_trace",
      (char*)&sqlite4WhereTrace, TCL_LINK_INT);
#endif
  Tcl_LinkVar(interp, "sqlite_static_bind_value",
      (char*)&sqlite_static_bind_value, TCL_LINK_STRING);
  Tcl_LinkVar(interp, "sqlite_static_bind_nbyte",







|







 







|







 







<
<







 







<
<
<
<







1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
....
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
....
4310
4311
4312
4313
4314
4315
4316


4317
4318
4319
4320
4321
4322
4323
....
4347
4348
4349
4350
4351
4352
4353




4354
4355
4356
4357
4358
4359
4360
  Tcl_Interp *interp;
  Tcl_Obj *pNeeded;
  Tcl_Obj *pDel;
};
typedef struct TestNeededX TestNeededX;

static void testCollationNeeded(void *pCtx, sqlite4 *db, const char *zReq){
  TestNeededX *p = (TestNeededX *)pCtx;
  Tcl_Obj *pScript;
  int rc;

  pScript = Tcl_DuplicateObj(p->pNeeded);
  Tcl_IncrRefCount(pScript);
  Tcl_ListObjAppendElement(0, pScript, Tcl_NewStringObj(zReq, -1));
  rc = Tcl_EvalObjEx(p->interp, pScript, TCL_EVAL_DIRECT|TCL_EVAL_GLOBAL);
................................................................................
  sqlite4_stmt *pStmt;
  int col;
  Tcl_Obj *pRet;
  const void *zName16;
  const void *(*xFunc)(sqlite4_stmt*, int, int*);
  int dummy;

  xFunc = (const void *(*)(sqlite4_stmt*, int, int*))clientData;
  if( objc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"",
       Tcl_GetString(objv[0]), " STMT column", 0);
    return TCL_ERROR;
  }

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
................................................................................
  extern int sqlite4_os_type;
#endif
#ifdef SQLITE4_DEBUG
  extern int sqlite4WhereTrace;
  extern int sqlite4OSTrace;
#endif
#ifdef SQLITE4_TEST


#ifdef SQLITE4_ENABLE_FTS3
  extern int sqlite4_fts3_enable_parentheses;
#endif
#endif

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
................................................................................
#endif
  Tcl_LinkVar(interp, "sqlite4_xferopt_count",
      (char*)&sqlite4_xferopt_count, TCL_LINK_INT);
#if SQLITE4_OS_WIN
  Tcl_LinkVar(interp, "sqlite_os_type",
      (char*)&sqlite4_os_type, TCL_LINK_INT);
#endif




#ifdef SQLITE4_DEBUG
  Tcl_LinkVar(interp, "sqlite_where_trace",
      (char*)&sqlite4WhereTrace, TCL_LINK_INT);
#endif
  Tcl_LinkVar(interp, "sqlite_static_bind_value",
      (char*)&sqlite_static_bind_value, TCL_LINK_STRING);
  Tcl_LinkVar(interp, "sqlite_static_bind_nbyte",

Changes to test/test_mem.c.

12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
#include <stdio.h>
#include <assert.h>
#include <string.h>

#include "sqliteInt.h"
#include "testInt.h"

#define MIN(x,y) ((x)<(y) ? (x) : (y))

#if defined(__GLIBC__)
  extern int backtrace(void**,int);
  extern void backtrace_symbols_fd(void*const*,int,int);
# define TM_BACKTRACE 12
#else
# define backtrace(A,B) 1
# define backtrace_symbols_fd(A,B,C)







<
<







12
13
14
15
16
17
18


19
20
21
22
23
24
25
#include <stdio.h>
#include <assert.h>
#include <string.h>

#include "sqliteInt.h"
#include "testInt.h"



#if defined(__GLIBC__)
  extern int backtrace(void**,int);
  extern void backtrace_symbols_fd(void*const*,int,int);
# define TM_BACKTRACE 12
#else
# define backtrace(A,B) 1
# define backtrace_symbols_fd(A,B,C)

Changes to test/tester.tcl.

491
492
493
494
495
496
497



498
499
500
501
502
503










504
505
506
507
508
509
510

  if {![info exists ::G(match)] || [string match $::G(match) $name]} {
    if {[catch {uplevel #0 "$cmd;\n"} result]} {
      puts "\nError: $result"
      fail_test $name
    } else {
      if {[regexp {^~?/.*/$} $expected]} {



        if {[string index $expected 0]=="~"} {
          set re [string map {# {[-0-9.]+}} [string range $expected 2 end-1]]
          set ok [expr {![regexp $re $result]}]
        } else {
          set re [string map {# {[-0-9.]+}} [string range $expected 1 end-1]]
          set ok [regexp $re $result]










        }
      } else {
        set ok [expr {[string compare $result $expected]==0}]
      }
      if {!$ok} {
        # if {![info exists ::testprefix] || $::testprefix eq ""} {
        #   error "no test prefix"







>
>
>






>
>
>
>
>
>
>
>
>
>







491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523

  if {![info exists ::G(match)] || [string match $::G(match) $name]} {
    if {[catch {uplevel #0 "$cmd;\n"} result]} {
      puts "\nError: $result"
      fail_test $name
    } else {
      if {[regexp {^~?/.*/$} $expected]} {
        # "expected" is of the form "/PATTERN/" then the result if correct if
        # regular expression PATTERN matches the result.  "~/PATTERN/" means
        # the regular expression must not match.
        if {[string index $expected 0]=="~"} {
          set re [string map {# {[-0-9.]+}} [string range $expected 2 end-1]]
          set ok [expr {![regexp $re $result]}]
        } else {
          set re [string map {# {[-0-9.]+}} [string range $expected 1 end-1]]
          set ok [regexp $re $result]
        }
      } elseif {[regexp {^~?\*.*\*$} $expected]} {
        # "expected" is of the form "*GLOB*" then the result if correct if
        # glob pattern GLOB matches the result.  "~/GLOB/" means
        # the glob must not match.
        if {[string index $expected 0]=="~"} {
          set e [string range $expected 1 end]
          set ok [expr {![string match $e $result]}]
        } else {
          set ok [string match $expected $result]
        }
      } else {
        set ok [expr {[string compare $result $expected]==0}]
      }
      if {!$ok} {
        # if {![info exists ::testprefix] || $::testprefix eq ""} {
        #   error "no test prefix"

Changes to test/tkt3442.test.

45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
# These tests perform an EXPLAIN QUERY PLAN on both versions of the 
# SELECT referenced in ticket #3442 (both '5000' and "5000") 
# and verify that the query plan is the same.
#
ifcapable explain {
  do_test tkt3442-1.2 {
    EQP { SELECT node FROM listhash WHERE id='5000' LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?) (~1 rows)}}
}


# Some extra tests testing other permutations of 5000.
#
ifcapable explain {
  do_test tkt3442-1.4 {
    EQP { SELECT node FROM listhash WHERE id=5000 LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?) (~1 rows)}}
}
do_test tkt3442-1.5 {
  catchsql {
    SELECT node FROM listhash WHERE id=[5000] LIMIT 1;
  }
} {1 {no such column: 5000}}

finish_test







|








|








45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
# These tests perform an EXPLAIN QUERY PLAN on both versions of the 
# SELECT referenced in ticket #3442 (both '5000' and "5000") 
# and verify that the query plan is the same.
#
ifcapable explain {
  do_test tkt3442-1.2 {
    EQP { SELECT node FROM listhash WHERE id='5000' LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?)}}
}


# Some extra tests testing other permutations of 5000.
#
ifcapable explain {
  do_test tkt3442-1.4 {
    EQP { SELECT node FROM listhash WHERE id=5000 LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?)}}
}
do_test tkt3442-1.5 {
  catchsql {
    SELECT node FROM listhash WHERE id=[5000] LIMIT 1;
  }
} {1 {no such column: 5000}}

finish_test

Changes to test/where.test.

59
60
61
62
63
64
65
66
67
68
69

70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
...
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152

153
154
155
156
157
158
159
...
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
....
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
proc count sql {
  kvwrap reset
  set res [execsql $sql]
  #puts "sql={$sql} seek=[kvwrap seek] step=[kvwrap step]"
  return [concat $res [expr [kvwrap step] + [kvwrap seek]]]
}

# Verify that queries use an index.  We are using the special variable
# "sqlite_search_count" which tallys the number of executions of MoveTo
# and Next operators in the VDBE.  By verifing that the search count is
# small we can be assured that indices are being used properly.

#
do_test where-1.1.1 {
  count {SELECT x, y, w FROM t1 WHERE w=10}
} {3 121 10 3}
do_test where-1.1.2 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.1.3 {
  db status step
} {0}
do_test where-1.1.4 {
  db eval {SELECT x, y, w FROM t1 WHERE +w=10}
} {3 121 10}
do_test where-1.1.5 {
  db status step
} {99}
do_test where-1.1.6 {
  set sqlite_query_plan
} {t1 {}}
do_test where-1.1.7 {
  count {SELECT x, y, w AS abc FROM t1 WHERE abc=10}
} {3 121 10 3}
do_test where-1.1.8 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.1.9 {
  db status step
} {0}
do_test where-1.2.1 {
  count {SELECT x, y, w FROM t1 WHERE w=11}
} {3 144 11 3}
do_test where-1.2.2 {
................................................................................
} {3 144 11 3}
do_test where-1.3.2 {
  count {SELECT x, y, w AS abc FROM t1 WHERE 11=abc}
} {3 144 11 3}
do_test where-1.4.1 {
  count {SELECT w, x, y FROM t1 WHERE 11=w AND x>2}
} {11 3 144 3}
do_test where-1.4.2 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.4.3 {
  count {SELECT w AS a, x AS b, y FROM t1 WHERE 11=a AND b>2}
} {11 3 144 3}
do_test where-1.4.4 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.5 {
  count {SELECT x, y FROM t1 WHERE y<200 AND w=11 AND x>2}
} {3 144 3}
do_test where-1.5.2 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.6 {
  count {SELECT x, y FROM t1 WHERE y<200 AND x>2 AND w=11}
} {3 144 3}
do_test where-1.7 {
  count {SELECT x, y FROM t1 WHERE w=11 AND y<200 AND x>2}
} {3 144 3}
do_test where-1.8 {
  count {SELECT x, y FROM t1 WHERE w>10 AND y=144 AND x=3}
} {3 144 3}
do_test where-1.8.2 {
  set sqlite_query_plan
} {t1 i1xy}
do_test where-1.8.3 {
  count {SELECT x, y FROM t1 WHERE y=144 AND x=3}
  set sqlite_query_plan
} {t1 i1xy}
do_test where-1.9 {
  count {SELECT x, y FROM t1 WHERE y=144 AND w>10 AND x=3}
} {3 144 3}
do_test where-1.10 {
  count {SELECT x, y FROM t1 WHERE x=3 AND w>=10 AND y=121}
} {3 121 3}
do_test where-1.11 {
  count {SELECT x, y FROM t1 WHERE x=3 AND y=100 AND w<10}
} {3 100 3}


# New for SQLite version 2.1: Verify that that inequality constraints
# are used correctly.
#
do_test where-1.12 {
  count {SELECT w FROM t1 WHERE x=3 AND y<100}
} {8 3}
................................................................................
do_test where-6.6 {
  cksort {
    SELECT * FROM t3 WHERE a>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.7 {
  # UPDATE: src4 does a sort here. It picks a different index because it
  # does not support the covering index optimization.
  cksort {
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 sort}

ifcapable subquery {
  do_test where-6.8 {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
    }
  } {1 100 4 2 99 9 3 98 16 sort}
}
do_test where-6.9.1 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.1.1 {
................................................................................
    CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT UNIQUE);
    INSERT INTO t8 VALUES(1,'one');
    INSERT INTO t8 VALUES(4,'four');
  }
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b
  } 
} {1/4 1/1 4/4 4/1 sort}
do_test where-14.2 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b DESC
  } 
} {1/1 1/4 4/1 4/4 sort}
do_test where-14.3 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, x.b
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.4 {
  cksort {







|
<
<
|
>




|
|
|









|
|
|



|
|
|







 







|
|
|



|
|
|



|
|
|









|
|
|
|
|
|
<









>







 







<
<



|






|







 







|




|







59
60
61
62
63
64
65
66


67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
...
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141

142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
...
509
510
511
512
513
514
515


516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
....
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
proc count sql {
  kvwrap reset
  set res [execsql $sql]
  #puts "sql={$sql} seek=[kvwrap seek] step=[kvwrap step]"
  return [concat $res [expr [kvwrap step] + [kvwrap seek]]]
}

# Verify that queries use an index. By verifing that the KVWrap layer


# xNext/xPrev/xSeek count is small we can be assured that indices are 
# being used properly.
#
do_test where-1.1.1 {
  count {SELECT x, y, w FROM t1 WHERE w=10}
} {3 121 10 3}
do_eqp_test where-1.1.2 {
  SELECT x, y, w FROM t1 WHERE w=10
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.1.3 {
  db status step
} {0}
do_test where-1.1.4 {
  db eval {SELECT x, y, w FROM t1 WHERE +w=10}
} {3 121 10}
do_test where-1.1.5 {
  db status step
} {99}
do_eqp_test where-1.1.6 {
  SELECT x, y, w FROM t1 WHERE +w=10
} {*SCAN TABLE t1*}
do_test where-1.1.7 {
  count {SELECT x, y, w AS abc FROM t1 WHERE abc=10}
} {3 121 10 3}
do_eqp_test where-1.1.8 {
  SELECT x, y, w AS abc FROM t1 WHERE abc=10
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.1.9 {
  db status step
} {0}
do_test where-1.2.1 {
  count {SELECT x, y, w FROM t1 WHERE w=11}
} {3 144 11 3}
do_test where-1.2.2 {
................................................................................
} {3 144 11 3}
do_test where-1.3.2 {
  count {SELECT x, y, w AS abc FROM t1 WHERE 11=abc}
} {3 144 11 3}
do_test where-1.4.1 {
  count {SELECT w, x, y FROM t1 WHERE 11=w AND x>2}
} {11 3 144 3}
do_eqp_test where-1.4.2 {
  SELECT w, x, y FROM t1 WHERE 11=w AND x>2
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.4.3 {
  count {SELECT w AS a, x AS b, y FROM t1 WHERE 11=a AND b>2}
} {11 3 144 3}
do_eqp_test where-1.4.4 {
  SELECT w AS a, x AS b, y FROM t1 WHERE 11=a AND b>2
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.5 {
  count {SELECT x, y FROM t1 WHERE y<200 AND w=11 AND x>2}
} {3 144 3}
do_eqp_test where-1.5.2 {
  SELECT x, y FROM t1 WHERE y<200 AND w=11 AND x>2
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.6 {
  count {SELECT x, y FROM t1 WHERE y<200 AND x>2 AND w=11}
} {3 144 3}
do_test where-1.7 {
  count {SELECT x, y FROM t1 WHERE w=11 AND y<200 AND x>2}
} {3 144 3}
do_test where-1.8 {
  count {SELECT x, y FROM t1 WHERE w>10 AND y=144 AND x=3}
} {3 144 3}
do_eqp_test where-1.8.2 {
  SELECT x, y FROM t1 WHERE w>10 AND y=144 AND x=3
} {*SEARCH TABLE t1 USING INDEX i1xy (x=? AND y=?)*}
do_eqp_test where-1.8.3 {
  SELECT x, y FROM t1 WHERE y=144 AND x=3
} {*SEARCH TABLE t1 USING INDEX i1xy (x=? AND y=?)*}

do_test where-1.9 {
  count {SELECT x, y FROM t1 WHERE y=144 AND w>10 AND x=3}
} {3 144 3}
do_test where-1.10 {
  count {SELECT x, y FROM t1 WHERE x=3 AND w>=10 AND y=121}
} {3 121 3}
do_test where-1.11 {
  count {SELECT x, y FROM t1 WHERE x=3 AND y=100 AND w<10}
} {3 100 3}


# New for SQLite version 2.1: Verify that that inequality constraints
# are used correctly.
#
do_test where-1.12 {
  count {SELECT w FROM t1 WHERE x=3 AND y<100}
} {8 3}
................................................................................
do_test where-6.6 {
  cksort {
    SELECT * FROM t3 WHERE a>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.7 {


  cksort {
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

ifcapable subquery {
  do_test where-6.8 {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
    }
  } {1 100 4 2 99 9 3 98 16 nosort}
}
do_test where-6.9.1 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.1.1 {
................................................................................
    CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT UNIQUE);
    INSERT INTO t8 VALUES(1,'one');
    INSERT INTO t8 VALUES(4,'four');
  }
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b
  } 
} {1/4 1/1 4/4 4/1 nosort}
do_test where-14.2 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b DESC
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.3 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, x.b
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.4 {
  cksort {

Changes to test/where7.test.

23328
23329
23330
23331
23332
23333
23334
23335
23336
23337
23338
23339
23340
23341
23342
23343
23344
23345
23346
23347
23348
  );
  CREATE INDEX t302_c3 on t302(c3);
  CREATE INDEX t302_c8_c3 on t302(c8, c3);
  CREATE INDEX t302_c5 on t302(c5);
  
  EXPLAIN QUERY PLAN
  SELECT t302.c1 
    FROM t302 JOIN t301 ON t302.c8 = t301.c8
    WHERE t302.c2 = 19571
      AND t302.c3 > 1287603136
      AND (t301.c4 = 1407449685622784
           OR t301.c8 = 1407424651264000)
   ORDER BY t302.c5 LIMIT 200;
} {
  0 0 1 {SEARCH TABLE t301 USING INDEX t301_c4 (c4=?) (~5 rows)} 
  0 0 1 {SEARCH TABLE t301 USING PRIMARY KEY (c8=?) (~1 rows)} 
  0 1 0 {SEARCH TABLE t302 USING INDEX t302_c8_c3 (c8=? AND c3>?) (~2 rows)} 
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}

finish_test







|






|
|
|




23328
23329
23330
23331
23332
23333
23334
23335
23336
23337
23338
23339
23340
23341
23342
23343
23344
23345
23346
23347
23348
  );
  CREATE INDEX t302_c3 on t302(c3);
  CREATE INDEX t302_c8_c3 on t302(c8, c3);
  CREATE INDEX t302_c5 on t302(c5);
  
  EXPLAIN QUERY PLAN
  SELECT t302.c1 
    FROM t302 JOIN t301 ON t302.c8 = +t301.c8
    WHERE t302.c2 = 19571
      AND t302.c3 > 1287603136
      AND (t301.c4 = 1407449685622784
           OR t301.c8 = 1407424651264000)
   ORDER BY t302.c5 LIMIT 200;
} {
  0 0 1 {SEARCH TABLE t301 USING INDEX t301_c4 (c4=?)}
  0 0 1 {SEARCH TABLE t301 USING INDEX t301 (c8=?)}
  0 1 0 {SEARCH TABLE t302 USING INDEX t302_c8_c3 (c8=? AND c3>?)}
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}

finish_test

Changes to test/where8.test.

252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
...
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
  # The "OR c = 'IX'" term forces a linear scan.
  execsql_status2 {
    SELECT a, d 
    FROM t1, t2 
    WHERE (a = 2 OR b = 'three' OR c = 'IX') AND (d = a OR e = 'sixteen')
    ORDER BY t1.rowid
  }
} {2 2 2 4 3 3 3 4 9 9 9 4 0 0 seek=13 step=16}
do_test where8-3.10 {
  execsql_status {
    SELECT d FROM t2 WHERE e IS NULL OR e = 'four'
  }
} {1 3 5 10 2 0 0}

do_test where8-3.11 {
................................................................................
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 0 0}
do_test where8-3.12 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 0 0}
do_test where8-3.13 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5
  }
} {1 1 2 2 3 3 4 2 4 4 9 0}

do_test where8-3.14 {







|







 







|







252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
...
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
  # The "OR c = 'IX'" term forces a linear scan.
  execsql_status2 {
    SELECT a, d 
    FROM t1, t2 
    WHERE (a = 2 OR b = 'three' OR c = 'IX') AND (d = a OR e = 'sixteen')
    ORDER BY t1.rowid
  }
} {2 2 2 4 3 3 3 4 9 9 9 4 9 0 seek=13 step=16}
do_test where8-3.10 {
  execsql_status {
    SELECT d FROM t2 WHERE e IS NULL OR e = 'four'
  }
} {1 3 5 10 2 0 0}

do_test where8-3.11 {
................................................................................
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 0 0}
do_test where8-3.12 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 9 0}
do_test where8-3.13 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5
  }
} {1 1 2 2 3 3 4 2 4 4 9 0}

do_test where8-3.14 {