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Overview
Comment:Add the ability to use indices for the first few terms of an ORDER BY clause, then sort in batches to handle the later terms.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:fa06a6fed9f48322d9b89721799ba12c46efa898
User & Date: drh 2014-03-21 20:58:42
Context
2014-03-22
00:27
Fix the ORDER BY optimization logic so that it will do a block-sort on a partial DESC ORDER BY. This enhancement uncovered a memory leak in pushUntoSorter() which is also fixed. check-in: c36f7461 user: drh tags: trunk
2014-03-21
20:58
Add the ability to use indices for the first few terms of an ORDER BY clause, then sort in batches to handle the later terms. check-in: fa06a6fe user: drh tags: trunk
19:56
Change the names of SRT_DistTable and SRT_Table used by CTE to more meaningful SRT_DistFifo and SRT_Fifo, respectively. Simplify the IgnorableOrderby() macro in the process. check-in: 45d8cc67 user: drh tags: trunk
18:45
Merge the OFFSET-on-query-without-FROM fix from trunk. check-in: 71e9ae72 user: drh tags: orderby-planning
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/btree.c.

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    ** a no-op).  */
    invalidateIncrblobCursors(p, 0, 1);
    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
  }
  sqlite3BtreeLeave(p);
  return rc;
}










/*
** Erase all information in a table and add the root of the table to
** the freelist.  Except, the root of the principle table (the one on
** page 1) is never added to the freelist.
**
** This routine will fail with SQLITE_LOCKED if there are any open







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    ** a no-op).  */
    invalidateIncrblobCursors(p, 0, 1);
    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Delete all information from the single table that pCur is open on.
**
** This routine only work for pCur on an ephemeral table.
*/
int sqlite3BtreeClearTableOfCursor(BtCursor *pCur){
  return sqlite3BtreeClearTable(pCur->pBtree, pCur->pgnoRoot, 0);
}

/*
** Erase all information in a table and add the root of the table to
** the freelist.  Except, the root of the principle table (the one on
** page 1) is never added to the freelist.
**
** This routine will fail with SQLITE_LOCKED if there are any open

Changes to src/btree.h.

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** indices.)
*/
#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
#define BTREE_BLOBKEY    2    /* Table has keys only - no data */

int sqlite3BtreeDropTable(Btree*, int, int*);
int sqlite3BtreeClearTable(Btree*, int, int*);

void sqlite3BtreeTripAllCursors(Btree*, int);

void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);

int sqlite3BtreeNewDb(Btree *p);








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** indices.)
*/
#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
#define BTREE_BLOBKEY    2    /* Table has keys only - no data */

int sqlite3BtreeDropTable(Btree*, int, int*);
int sqlite3BtreeClearTable(Btree*, int, int*);
int sqlite3BtreeClearTableOfCursor(BtCursor*);
void sqlite3BtreeTripAllCursors(Btree*, int);

void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);

int sqlite3BtreeNewDb(Btree *p);

Changes to src/expr.c.

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ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
  ExprList *pNew;
  struct ExprList_item *pItem, *pOldItem;
  int i;
  if( p==0 ) return 0;
  pNew = sqlite3DbMallocRaw(db, sizeof(*pNew) );
  if( pNew==0 ) return 0;
  pNew->iECursor = 0;
  pNew->nExpr = i = p->nExpr;
  if( (flags & EXPRDUP_REDUCE)==0 ) for(i=1; i<p->nExpr; i+=i){}
  pNew->a = pItem = sqlite3DbMallocRaw(db,  i*sizeof(p->a[0]) );
  if( pItem==0 ){
    sqlite3DbFree(db, pNew);
    return 0;
  } 
................................................................................
  pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
  pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);
  return pNew;
}
#else
Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
  assert( p==0 );
................................................................................
** Generate code to move content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
*/
void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
  int i;
  struct yColCache *p;
  assert( iFrom>=iTo+nReg || iFrom+nReg<=iTo );
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg-1);
  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
    int x = p->iReg;
    if( x>=iFrom && x<iFrom+nReg ){
      p->iReg += iTo-iFrom;
    }
  }
}
................................................................................
            testcase( pDef->funcFlags & OPFLAG_LENGTHARG );
            pFarg->a[0].pExpr->op2 = 
                  pDef->funcFlags & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG);
          }
        }

        sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
        sqlite3ExprCodeExprList(pParse, pFarg, r1, 
                                SQLITE_ECEL_DUP|SQLITE_ECEL_FACTOR);
        sqlite3ExprCachePop(pParse, 1);   /* Ticket 2ea2425d34be */
      }else{
        r1 = 0;
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is







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ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
  ExprList *pNew;
  struct ExprList_item *pItem, *pOldItem;
  int i;
  if( p==0 ) return 0;
  pNew = sqlite3DbMallocRaw(db, sizeof(*pNew) );
  if( pNew==0 ) return 0;

  pNew->nExpr = i = p->nExpr;
  if( (flags & EXPRDUP_REDUCE)==0 ) for(i=1; i<p->nExpr; i+=i){}
  pNew->a = pItem = sqlite3DbMallocRaw(db,  i*sizeof(p->a[0]) );
  if( pItem==0 ){
    sqlite3DbFree(db, pNew);
    return 0;
  } 
................................................................................
  pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
  pNew->pOffset = sqlite3ExprDup(db, p->pOffset, flags);
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;

  pNew->nSelectRow = p->nSelectRow;
  pNew->pWith = withDup(db, p->pWith);
  return pNew;
}
#else
Select *sqlite3SelectDup(sqlite3 *db, Select *p, int flags){
  assert( p==0 );
................................................................................
** Generate code to move content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
*/
void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
  int i;
  struct yColCache *p;
  assert( iFrom>=iTo+nReg || iFrom+nReg<=iTo );
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
    int x = p->iReg;
    if( x>=iFrom && x<iFrom+nReg ){
      p->iReg += iTo-iFrom;
    }
  }
}
................................................................................
            testcase( pDef->funcFlags & OPFLAG_LENGTHARG );
            pFarg->a[0].pExpr->op2 = 
                  pDef->funcFlags & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG);
          }
        }

        sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
        sqlite3ExprCodeExprList(pParse, pFarg, r1,
                                SQLITE_ECEL_DUP|SQLITE_ECEL_FACTOR);
        sqlite3ExprCachePop(pParse, 1);   /* Ticket 2ea2425d34be */
      }else{
        r1 = 0;
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is

Changes to src/pragma.c.

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      /* Do the b-tree integrity checks */
      sqlite3VdbeAddOp3(v, OP_IntegrityCk, 2, cnt, 1);
      sqlite3VdbeChangeP5(v, (u8)i);
      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2); VdbeCoverage(v);
      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zName),
         P4_DYNAMIC);
      sqlite3VdbeAddOp2(v, OP_Move, 2, 4);
      sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 2);
      sqlite3VdbeAddOp2(v, OP_ResultRow, 2, 1);
      sqlite3VdbeJumpHere(v, addr);

      /* Make sure all the indices are constructed correctly.
      */
      for(x=sqliteHashFirst(pTbls); x && !isQuick; x=sqliteHashNext(x)){







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      /* Do the b-tree integrity checks */
      sqlite3VdbeAddOp3(v, OP_IntegrityCk, 2, cnt, 1);
      sqlite3VdbeChangeP5(v, (u8)i);
      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2); VdbeCoverage(v);
      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zName),
         P4_DYNAMIC);
      sqlite3VdbeAddOp3(v, OP_Move, 2, 4, 1);
      sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 2);
      sqlite3VdbeAddOp2(v, OP_ResultRow, 2, 1);
      sqlite3VdbeJumpHere(v, addr);

      /* Make sure all the indices are constructed correctly.
      */
      for(x=sqliteHashFirst(pTbls); x && !isQuick; x=sqliteHashNext(x)){

Changes to src/select.c.

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**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
*/
#include "sqliteInt.h"






























/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
*/
static void clearSelect(sqlite3 *db, Select *p){
  sqlite3ExprListDelete(db, p->pEList);
................................................................................
  pNew->selFlags = selFlags;
  pNew->op = TK_SELECT;
  pNew->pLimit = pLimit;
  pNew->pOffset = pOffset;
  assert( pOffset==0 || pLimit!=0 );
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  if( db->mallocFailed ) {
    clearSelect(db, pNew);
    if( pNew!=&standin ) sqlite3DbFree(db, pNew);
    pNew = 0;
  }else{
    assert( pNew->pSrc!=0 || pParse->nErr>0 );
  }
................................................................................
                     isOuter, &p->pWhere);
      }
    }
  }
  return 0;
}









/*
** Insert code into "v" that will push the record on the top of the
** stack into the sorter.
*/
static void pushOntoSorter(
  Parse *pParse,         /* Parser context */
  ExprList *pOrderBy,    /* The ORDER BY clause */
  Select *pSelect,       /* The whole SELECT statement */
  int regData            /* Register holding data to be sorted */
){
  Vdbe *v = pParse->pVdbe;
  int nExpr = pOrderBy->nExpr;
  int regBase = sqlite3GetTempRange(pParse, nExpr+2);
  int regRecord = sqlite3GetTempReg(pParse);

  int op;
  sqlite3ExprCacheClear(pParse);
  sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
  sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
  if( pSelect->selFlags & SF_UseSorter ){



























    op = OP_SorterInsert;
  }else{
    op = OP_IdxInsert;
  }
  sqlite3VdbeAddOp2(v, op, pOrderBy->iECursor, regRecord);

  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);

  if( pSelect->iLimit ){
    int addr1, addr2;
    int iLimit;
    if( pSelect->iOffset ){
      iLimit = pSelect->iOffset+1;
    }else{
      iLimit = pSelect->iLimit;
    }
    addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit); VdbeCoverage(v);
    sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
    addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
    sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
    sqlite3VdbeJumpHere(v, addr2);
  }
}

/*
** Add code to implement the OFFSET
*/
................................................................................
    return 1;
  }else{
    return 0;
  }
}
#endif

/*
** An instance of the following object is used to record information about
** how to process the DISTINCT keyword, to simplify passing that information
** into the selectInnerLoop() routine.
*/
typedef struct DistinctCtx DistinctCtx;
struct DistinctCtx {
  u8 isTnct;      /* True if the DISTINCT keyword is present */
  u8 eTnctType;   /* One of the WHERE_DISTINCT_* operators */
  int tabTnct;    /* Ephemeral table used for DISTINCT processing */
  int addrTnct;   /* Address of OP_OpenEphemeral opcode for tabTnct */
};

/*
** This routine generates the code for the inside of the inner loop
** of a SELECT.
**
** If srcTab is negative, then the pEList expressions
** are evaluated in order to get the data for this row.  If srcTab is
** zero or more, then data is pulled from srcTab and pEList is used only 
................................................................................
** to get number columns and the datatype for each column.
*/
static void selectInnerLoop(
  Parse *pParse,          /* The parser context */
  Select *p,              /* The complete select statement being coded */
  ExprList *pEList,       /* List of values being extracted */
  int srcTab,             /* Pull data from this table */
  ExprList *pOrderBy,     /* If not NULL, sort results using this key */
  DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */
  SelectDest *pDest,      /* How to dispose of the results */
  int iContinue,          /* Jump here to continue with next row */
  int iBreak              /* Jump here to break out of the inner loop */
){
  Vdbe *v = pParse->pVdbe;
  int i;
................................................................................
  int eDest = pDest->eDest;   /* How to dispose of results */
  int iParm = pDest->iSDParm; /* First argument to disposal method */
  int nResultCol;             /* Number of result columns */

  assert( v );
  assert( pEList!=0 );
  hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP;

  if( pOrderBy==0 && !hasDistinct ){
    assert( iContinue!=0 );
    codeOffset(v, p->iOffset, iContinue);
  }

  /* Pull the requested columns.
  */
  nResultCol = pEList->nExpr;
................................................................................

      default: {
        assert( pDistinct->eTnctType==WHERE_DISTINCT_UNORDERED );
        codeDistinct(pParse, pDistinct->tabTnct, iContinue, nResultCol, regResult);
        break;
      }
    }
    if( pOrderBy==0 ){
      codeOffset(v, p->iOffset, iContinue);
    }
  }

  switch( eDest ){
    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
................................................................................
        ** on an ephemeral index. If the current row is already present
        ** in the index, do not write it to the output. If not, add the
        ** current row to the index and proceed with writing it to the
        ** output table as well.  */
        int addr = sqlite3VdbeCurrentAddr(v) + 4;
        sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0); VdbeCoverage(v);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r1);
        assert( pOrderBy==0 );
      }
#endif
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p, r1);
      }else{
        int r2 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
        sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
        sqlite3ReleaseTempReg(pParse, r2);
      }
................................................................................
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      assert( nResultCol==1 );
      pDest->affSdst =
                  sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst);
      if( pOrderBy ){
        /* At first glance you would think we could optimize out the
        ** ORDER BY in this case since the order of entries in the set
        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */
        pushOntoSorter(pParse, pOrderBy, p, regResult);
      }else{
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult,1,r1, &pDest->affSdst, 1);
        sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }
................................................................................

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell and break out
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( nResultCol==1 );
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p, regResult);
      }else{
        sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    case SRT_Coroutine:       /* Send data to a co-routine */
    case SRT_Output: {        /* Return the results */
      testcase( eDest==SRT_Coroutine );
      testcase( eDest==SRT_Output );
      if( pOrderBy ){
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
        pushOntoSorter(pParse, pOrderBy, p, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }else if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
      }else{
        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol);
        sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol);
      }
................................................................................
#endif
  }

  /* Jump to the end of the loop if the LIMIT is reached.  Except, if
  ** there is a sorter, in which case the sorter has already limited
  ** the output for us.
  */
  if( pOrderBy==0 && p->iLimit ){
    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1); VdbeCoverage(v);
  }
}

/*
** Allocate a KeyInfo object sufficient for an index of N key columns and
** X extra columns.
................................................................................
** then the KeyInfo structure is appropriate for initializing a virtual
** index to implement a DISTINCT test.
**
** Space to hold the KeyInfo structure is obtain from malloc.  The calling
** function is responsible for seeing that this structure is eventually
** freed.
*/
static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList, int nExtra){





  int nExpr;
  KeyInfo *pInfo;
  struct ExprList_item *pItem;
  sqlite3 *db = pParse->db;
  int i;

  nExpr = pList->nExpr;
  pInfo = sqlite3KeyInfoAlloc(db, nExpr+nExtra, 1);
  if( pInfo ){
    assert( sqlite3KeyInfoIsWriteable(pInfo) );
    for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
      CollSeq *pColl;
      pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
      if( !pColl ) pColl = db->pDfltColl;
      pInfo->aColl[i] = pColl;
      pInfo->aSortOrder[i] = pItem->sortOrder;
    }
  }
  return pInfo;
}

#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
................................................................................
** then the results were placed in a sorter.  After the loop is terminated
** we need to run the sorter and output the results.  The following
** routine generates the code needed to do that.
*/
static void generateSortTail(
  Parse *pParse,    /* Parsing context */
  Select *p,        /* The SELECT statement */
  Vdbe *v,          /* Generate code into this VDBE */
  int nColumn,      /* Number of columns of data */
  SelectDest *pDest /* Write the sorted results here */
){

  int addrBreak = sqlite3VdbeMakeLabel(v);     /* Jump here to exit loop */
  int addrContinue = sqlite3VdbeMakeLabel(v);  /* Jump here for next cycle */
  int addr;

  int iTab;
  int pseudoTab = 0;
  ExprList *pOrderBy = p->pOrderBy;

  int eDest = pDest->eDest;
  int iParm = pDest->iSDParm;

  int regRow;
  int regRowid;








  iTab = pOrderBy->iECursor;
  regRow = sqlite3GetTempReg(pParse);
  if( eDest==SRT_Output || eDest==SRT_Coroutine ){
    pseudoTab = pParse->nTab++;
    sqlite3VdbeAddOp3(v, OP_OpenPseudo, pseudoTab, regRow, nColumn);
    regRowid = 0;
  }else{
    regRowid = sqlite3GetTempReg(pParse);
  }
  if( p->selFlags & SF_UseSorter ){

    int regSortOut = ++pParse->nMem;
    int ptab2 = pParse->nTab++;
    sqlite3VdbeAddOp3(v, OP_OpenPseudo, ptab2, regSortOut, pOrderBy->nExpr+2);

    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
    VdbeCoverage(v);
    codeOffset(v, p->iOffset, addrContinue);
    sqlite3VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
    sqlite3VdbeAddOp3(v, OP_Column, ptab2, pOrderBy->nExpr+1, regRow);
    sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
  }else{

    addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak); VdbeCoverage(v);
    codeOffset(v, p->iOffset, addrContinue);
    sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr+1, regRow);
  }
  switch( eDest ){
    case SRT_Table:
    case SRT_EphemTab: {
      testcase( eDest==SRT_Table );
      testcase( eDest==SRT_EphemTab );
      sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
................................................................................
  }
  sqlite3ReleaseTempReg(pParse, regRow);
  sqlite3ReleaseTempReg(pParse, regRowid);

  /* The bottom of the loop
  */
  sqlite3VdbeResolveLabel(v, addrContinue);
  if( p->selFlags & SF_UseSorter ){
    sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr); VdbeCoverage(v);
  }else{
    sqlite3VdbeAddOp2(v, OP_Next, iTab, addr); VdbeCoverage(v);
  }

  sqlite3VdbeResolveLabel(v, addrBreak);
  if( eDest==SRT_Output || eDest==SRT_Coroutine ){
    sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
  }
}

/*
................................................................................
      Expr *pE = pFunc->pExpr;
      assert( !ExprHasProperty(pE, EP_xIsSelect) );
      if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
        sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
           "argument");
        pFunc->iDistinct = -1;
      }else{
        KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList, 0);
        sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
                          (char*)pKeyInfo, P4_KEYINFO);
      }
    }
  }
}

................................................................................
  int i, j;              /* Loop counters */
  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
  Vdbe *v;               /* The virtual machine under construction */
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int rc = 1;            /* Value to return from this function */
  int addrSortIndex;     /* Address of an OP_OpenEphemeral instruction */
  DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */

  AggInfo sAggInfo;      /* Information used by aggregate queries */
  int iEnd;              /* Address of the end of the query */
  sqlite3 *db;           /* The database connection */

#ifndef SQLITE_OMIT_EXPLAIN
  int iRestoreSelectId = pParse->iSelectId;
  pParse->iSelectId = pParse->iNextSelectId++;
................................................................................
    /* If ORDER BY makes no difference in the output then neither does
    ** DISTINCT so it can be removed too. */
    sqlite3ExprListDelete(db, p->pOrderBy);
    p->pOrderBy = 0;
    p->selFlags &= ~SF_Distinct;
  }
  sqlite3SelectPrep(pParse, p, 0);

  pOrderBy = p->pOrderBy;
  pTabList = p->pSrc;
  pEList = p->pEList;
  if( pParse->nErr || db->mallocFailed ){
    goto select_end;
  }
  isAgg = (p->selFlags & SF_Aggregate)!=0;
  assert( pEList!=0 );
................................................................................
    }
    if( /*pParse->nErr ||*/ db->mallocFailed ){
      goto select_end;
    }
    pParse->nHeight -= sqlite3SelectExprHeight(p);
    pTabList = p->pSrc;
    if( !IgnorableOrderby(pDest) ){
      pOrderBy = p->pOrderBy;
    }
  }
  pEList = p->pEList;
#endif
  pWhere = p->pWhere;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
................................................................................
  /* If there is both a GROUP BY and an ORDER BY clause and they are
  ** identical, then disable the ORDER BY clause since the GROUP BY
  ** will cause elements to come out in the correct order.  This is
  ** an optimization - the correct answer should result regardless.
  ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER
  ** to disable this optimization for testing purposes.
  */
  if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy, -1)==0
         && OptimizationEnabled(db, SQLITE_GroupByOrder) ){
    pOrderBy = 0;
  }

  /* If the query is DISTINCT with an ORDER BY but is not an aggregate, and 
  ** if the select-list is the same as the ORDER BY list, then this query
  ** can be rewritten as a GROUP BY. In other words, this:
  **
  **     SELECT DISTINCT xyz FROM ... ORDER BY xyz
................................................................................
  **
  ** The second form is preferred as a single index (or temp-table) may be 
  ** used for both the ORDER BY and DISTINCT processing. As originally 
  ** written the query must use a temp-table for at least one of the ORDER 
  ** BY and DISTINCT, and an index or separate temp-table for the other.
  */
  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct 
   && sqlite3ExprListCompare(pOrderBy, p->pEList, -1)==0
  ){
    p->selFlags &= ~SF_Distinct;
    p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
    pGroupBy = p->pGroupBy;
    pOrderBy = 0;
    /* Notice that even thought SF_Distinct has been cleared from p->selFlags,
    ** the sDistinct.isTnct is still set.  Hence, isTnct represents the
    ** original setting of the SF_Distinct flag, not the current setting */
    assert( sDistinct.isTnct );
  }

  /* If there is an ORDER BY clause, then this sorting
  ** index might end up being unused if the data can be 
  ** extracted in pre-sorted order.  If that is the case, then the
  ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
  ** we figure out that the sorting index is not needed.  The addrSortIndex
  ** variable is used to facilitate that change.
  */
  if( pOrderBy ){
    KeyInfo *pKeyInfo;
    pKeyInfo = keyInfoFromExprList(pParse, pOrderBy, 0);
    pOrderBy->iECursor = pParse->nTab++;
    p->addrOpenEphm[2] = addrSortIndex =
      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
                           pOrderBy->iECursor, pOrderBy->nExpr+2, 0,
                           (char*)pKeyInfo, P4_KEYINFO);
  }else{
    addrSortIndex = -1;
  }

  /* If the output is destined for a temporary table, open that table.
  */
  if( pDest->eDest==SRT_EphemTab ){
    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr);
  }

  /* Set the limiter.
  */
  iEnd = sqlite3VdbeMakeLabel(v);
  p->nSelectRow = LARGEST_INT64;
  computeLimitRegisters(pParse, p, iEnd);
  if( p->iLimit==0 && addrSortIndex>=0 ){
    sqlite3VdbeGetOp(v, addrSortIndex)->opcode = OP_SorterOpen;
    p->selFlags |= SF_UseSorter;
  }

  /* Open a virtual index to use for the distinct set.
  */
  if( p->selFlags & SF_Distinct ){
    sDistinct.tabTnct = pParse->nTab++;
    sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
                                sDistinct.tabTnct, 0, 0,
                                (char*)keyInfoFromExprList(pParse, p->pEList, 0),
                                P4_KEYINFO);
    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
    sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED;
  }else{
    sDistinct.eTnctType = WHERE_DISTINCT_NOOP;
  }

  if( !isAgg && pGroupBy==0 ){
    /* No aggregate functions and no GROUP BY clause */
    u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0);

    /* Begin the database scan. */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pOrderBy, p->pEList,
                               wctrlFlags, 0);
    if( pWInfo==0 ) goto select_end;
    if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
      p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
    }
    if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){
      sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo);
    }

    if( pOrderBy && sqlite3WhereIsOrdered(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 ){
      sqlite3VdbeChangeToNoop(v, addrSortIndex);
      p->addrOpenEphm[2] = -1;
    }

    /* Use the standard inner loop. */
    selectInnerLoop(pParse, p, pEList, -1, pOrderBy, &sDistinct, pDest,
                    sqlite3WhereContinueLabel(pWInfo),
                    sqlite3WhereBreakLabel(pWInfo));

    /* End the database scan loop.
    */
    sqlite3WhereEnd(pWInfo);
  }else{
................................................................................
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;
    sNC.pAggInfo = &sAggInfo;
    sAggInfo.mnReg = pParse->nMem+1;
    sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
    sAggInfo.pGroupBy = pGroupBy;
    sqlite3ExprAnalyzeAggList(&sNC, pEList);
    sqlite3ExprAnalyzeAggList(&sNC, pOrderBy);
    if( pHaving ){
      sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
    }
    sAggInfo.nAccumulator = sAggInfo.nColumn;
    for(i=0; i<sAggInfo.nFunc; i++){
      assert( !ExprHasProperty(sAggInfo.aFunc[i].pExpr, EP_xIsSelect) );
      sNC.ncFlags |= NC_InAggFunc;
................................................................................

      /* If there is a GROUP BY clause we might need a sorting index to
      ** implement it.  Allocate that sorting index now.  If it turns out
      ** that we do not need it after all, the OP_SorterOpen instruction
      ** will be converted into a Noop.  
      */
      sAggInfo.sortingIdx = pParse->nTab++;
      pKeyInfo = keyInfoFromExprList(pParse, pGroupBy, 0);
      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen, 
          sAggInfo.sortingIdx, sAggInfo.nSortingColumn, 
          0, (char*)pKeyInfo, P4_KEYINFO);

      /* Initialize memory locations used by GROUP BY aggregate processing
      */
      iUseFlag = ++pParse->nMem;
................................................................................

      /* 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.
      */
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, 0, 
                                 WHERE_GROUPBY, 0);
      if( pWInfo==0 ) goto select_end;
      if( sqlite3WhereIsOrdered(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;
      }else{
        /* Rows are coming out in undetermined order.  We have to push
................................................................................
      sqlite3VdbeResolveLabel(v, addrOutputRow);
      addrOutputRow = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2); VdbeCoverage(v);
      VdbeComment((v, "Groupby result generator entry point"));
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      finalizeAggFunctions(pParse, &sAggInfo);
      sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
      selectInnerLoop(pParse, p, p->pEList, -1, pOrderBy,
                      &sDistinct, pDest,
                      addrOutputRow+1, addrSetAbort);
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      VdbeComment((v, "end groupby result generator"));

      /* Generate a subroutine that will reset the group-by accumulator
      */
................................................................................
        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMax,0,flag,0);
        if( pWInfo==0 ){
          sqlite3ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        assert( pMinMax==0 || pMinMax->nExpr==1 );
        if( sqlite3WhereIsOrdered(pWInfo) ){
          sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3WhereBreakLabel(pWInfo));
          VdbeComment((v, "%s() by index",
                (flag==WHERE_ORDERBY_MIN?"min":"max")));
        }
        sqlite3WhereEnd(pWInfo);
        finalizeAggFunctions(pParse, &sAggInfo);
      }

      pOrderBy = 0;
      sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
      selectInnerLoop(pParse, p, p->pEList, -1, 0, 0, 
                      pDest, addrEnd, addrEnd);
      sqlite3ExprListDelete(db, pDel);
    }
    sqlite3VdbeResolveLabel(v, addrEnd);
    
................................................................................
  if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){
    explainTempTable(pParse, "DISTINCT");
  }

  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( pOrderBy ){
    explainTempTable(pParse, "ORDER BY");
    generateSortTail(pParse, p, v, pEList->nExpr, pDest);
  }

  /* Jump here to skip this query
  */
  sqlite3VdbeResolveLabel(v, iEnd);

  /* The SELECT was successfully coded.   Set the return code to 0







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**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
*/
#include "sqliteInt.h"

/*
** An instance of the following object is used to record information about
** how to process the DISTINCT keyword, to simplify passing that information
** into the selectInnerLoop() routine.
*/
typedef struct DistinctCtx DistinctCtx;
struct DistinctCtx {
  u8 isTnct;      /* True if the DISTINCT keyword is present */
  u8 eTnctType;   /* One of the WHERE_DISTINCT_* operators */
  int tabTnct;    /* Ephemeral table used for DISTINCT processing */
  int addrTnct;   /* Address of OP_OpenEphemeral opcode for tabTnct */
};

/*
** An instance of the following object is used to record information about
** the ORDER BY (or GROUP BY) clause of query is being coded.
*/
typedef struct SortCtx SortCtx;
struct SortCtx {
  ExprList *pOrderBy;   /* The ORDER BY (or GROUP BY clause) */
  int nOBSat;           /* Number of ORDER BY terms satisfied by indices */
  int iECursor;         /* Cursor number for the sorter */
  int regReturn;        /* Register holding block-output return address */
  int labelBkOut;       /* Start label for the block-output subroutine */
  int addrSortIndex;    /* Address of the OP_SorterOpen or OP_OpenEphemeral */
  u8 sortFlags;         /* Zero or more SORTFLAG_* bits */
};
#define SORTFLAG_UseSorter  0x01   /* Use SorterOpen instead of OpenEphemeral */

/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
*/
static void clearSelect(sqlite3 *db, Select *p){
  sqlite3ExprListDelete(db, p->pEList);
................................................................................
  pNew->selFlags = selFlags;
  pNew->op = TK_SELECT;
  pNew->pLimit = pLimit;
  pNew->pOffset = pOffset;
  assert( pOffset==0 || pLimit!=0 );
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;

  if( db->mallocFailed ) {
    clearSelect(db, pNew);
    if( pNew!=&standin ) sqlite3DbFree(db, pNew);
    pNew = 0;
  }else{
    assert( pNew->pSrc!=0 || pParse->nErr>0 );
  }
................................................................................
                     isOuter, &p->pWhere);
      }
    }
  }
  return 0;
}

/* Forward reference */
static KeyInfo *keyInfoFromExprList(
  Parse *pParse,       /* Parsing context */
  ExprList *pList,     /* Form the KeyInfo object from this ExprList */
  int iStart,          /* Begin with this column of pList */
  int nExtra           /* Add this many extra columns to the end */
);

/*
** Insert code into "v" that will push the record in register regData
** into the sorter.
*/
static void pushOntoSorter(
  Parse *pParse,         /* Parser context */
  SortCtx *pSort,        /* Information about the ORDER BY clause */
  Select *pSelect,       /* The whole SELECT statement */
  int regData            /* Register holding data to be sorted */
){
  Vdbe *v = pParse->pVdbe;
  int nExpr = pSort->pOrderBy->nExpr;
  int regBase = sqlite3GetTempRange(pParse, nExpr+2);
  int regRecord = sqlite3GetTempReg(pParse);
  int nOBSat = pSort->nOBSat;
  int op;
  sqlite3ExprCacheClear(pParse);
  sqlite3ExprCodeExprList(pParse, pSort->pOrderBy, regBase, 0);
  sqlite3VdbeAddOp2(v, OP_Sequence, pSort->iECursor, regBase+nExpr);
  sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nExpr+2-nOBSat, regRecord);

  if( nOBSat>0 ){
    int regPrevKey;   /* The first nOBSat columns of the previous row */
    int addrFirst;    /* Address of the OP_IfNot opcode */
    int addrJmp;      /* Address of the OP_Jump opcode */
    VdbeOp *pOp;      /* Opcode that opens the sorter */
    int nKey;         /* Number of sorting key columns, including OP_Sequence */

    regPrevKey = pParse->nMem+1;
    pParse->nMem += pSort->nOBSat;
    nKey = nExpr - pSort->nOBSat + 1;
    addrFirst = sqlite3VdbeAddOp1(v, OP_IfNot, regBase+nExpr); VdbeCoverage(v);
    sqlite3VdbeAddOp3(v, OP_Compare, regPrevKey, regBase, pSort->nOBSat);
    pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex);
    pOp->p2 = nKey + 1;
    sqlite3VdbeChangeP4(v, -1, (char*)pOp->p4.pKeyInfo, P4_KEYINFO);
    pOp->p4.pKeyInfo = keyInfoFromExprList(pParse, pSort->pOrderBy, nOBSat, 1);
    addrJmp = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp3(v, OP_Jump, addrJmp+1, 0, addrJmp+1); VdbeCoverage(v);
    pSort->labelBkOut = sqlite3VdbeMakeLabel(v);
    pSort->regReturn = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
    sqlite3VdbeAddOp1(v, OP_ResetSorter, pSort->iECursor);
    sqlite3VdbeJumpHere(v, addrFirst);
    sqlite3VdbeAddOp3(v, OP_Move, regBase, regPrevKey, pSort->nOBSat);
    sqlite3VdbeJumpHere(v, addrJmp);
  }
  if( pSort->sortFlags & SORTFLAG_UseSorter ){
    op = OP_SorterInsert;
  }else{
    op = OP_IdxInsert;
  }
  sqlite3VdbeAddOp2(v, op, pSort->iECursor, regRecord);
  if( nOBSat==0 ){
    sqlite3ReleaseTempReg(pParse, regRecord);
    sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
  }
  if( pSelect->iLimit ){
    int addr1, addr2;
    int iLimit;
    if( pSelect->iOffset ){
      iLimit = pSelect->iOffset+1;
    }else{
      iLimit = pSelect->iLimit;
    }
    addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit); VdbeCoverage(v);
    sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
    addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp1(v, OP_Last, pSort->iECursor);
    sqlite3VdbeAddOp1(v, OP_Delete, pSort->iECursor);
    sqlite3VdbeJumpHere(v, addr2);
  }
}

/*
** Add code to implement the OFFSET
*/
................................................................................
    return 1;
  }else{
    return 0;
  }
}
#endif














/*
** This routine generates the code for the inside of the inner loop
** of a SELECT.
**
** If srcTab is negative, then the pEList expressions
** are evaluated in order to get the data for this row.  If srcTab is
** zero or more, then data is pulled from srcTab and pEList is used only 
................................................................................
** to get number columns and the datatype for each column.
*/
static void selectInnerLoop(
  Parse *pParse,          /* The parser context */
  Select *p,              /* The complete select statement being coded */
  ExprList *pEList,       /* List of values being extracted */
  int srcTab,             /* Pull data from this table */
  SortCtx *pSort,         /* If not NULL, info on how to process ORDER BY */
  DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */
  SelectDest *pDest,      /* How to dispose of the results */
  int iContinue,          /* Jump here to continue with next row */
  int iBreak              /* Jump here to break out of the inner loop */
){
  Vdbe *v = pParse->pVdbe;
  int i;
................................................................................
  int eDest = pDest->eDest;   /* How to dispose of results */
  int iParm = pDest->iSDParm; /* First argument to disposal method */
  int nResultCol;             /* Number of result columns */

  assert( v );
  assert( pEList!=0 );
  hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP;
  if( pSort && pSort->pOrderBy==0 ) pSort = 0;
  if( pSort==0 && !hasDistinct ){
    assert( iContinue!=0 );
    codeOffset(v, p->iOffset, iContinue);
  }

  /* Pull the requested columns.
  */
  nResultCol = pEList->nExpr;
................................................................................

      default: {
        assert( pDistinct->eTnctType==WHERE_DISTINCT_UNORDERED );
        codeDistinct(pParse, pDistinct->tabTnct, iContinue, nResultCol, regResult);
        break;
      }
    }
    if( pSort==0 ){
      codeOffset(v, p->iOffset, iContinue);
    }
  }

  switch( eDest ){
    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
................................................................................
        ** on an ephemeral index. If the current row is already present
        ** in the index, do not write it to the output. If not, add the
        ** current row to the index and proceed with writing it to the
        ** output table as well.  */
        int addr = sqlite3VdbeCurrentAddr(v) + 4;
        sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0); VdbeCoverage(v);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r1);
        assert( pSort==0 );
      }
#endif
      if( pSort ){
        pushOntoSorter(pParse, pSort, p, r1);
      }else{
        int r2 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
        sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
        sqlite3ReleaseTempReg(pParse, r2);
      }
................................................................................
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      assert( nResultCol==1 );
      pDest->affSdst =
                  sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst);
      if( pSort ){
        /* At first glance you would think we could optimize out the
        ** ORDER BY in this case since the order of entries in the set
        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */
        pushOntoSorter(pParse, pSort, p, regResult);
      }else{
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult,1,r1, &pDest->affSdst, 1);
        sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }
................................................................................

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell and break out
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( nResultCol==1 );
      if( pSort ){
        pushOntoSorter(pParse, pSort, p, regResult);
      }else{
        sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    case SRT_Coroutine:       /* Send data to a co-routine */
    case SRT_Output: {        /* Return the results */
      testcase( eDest==SRT_Coroutine );
      testcase( eDest==SRT_Output );
      if( pSort ){
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
        pushOntoSorter(pParse, pSort, p, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }else if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
      }else{
        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol);
        sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol);
      }
................................................................................
#endif
  }

  /* Jump to the end of the loop if the LIMIT is reached.  Except, if
  ** there is a sorter, in which case the sorter has already limited
  ** the output for us.
  */
  if( pSort==0 && p->iLimit ){
    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1); VdbeCoverage(v);
  }
}

/*
** Allocate a KeyInfo object sufficient for an index of N key columns and
** X extra columns.
................................................................................
** then the KeyInfo structure is appropriate for initializing a virtual
** index to implement a DISTINCT test.
**
** Space to hold the KeyInfo structure is obtain from malloc.  The calling
** function is responsible for seeing that this structure is eventually
** freed.
*/
static KeyInfo *keyInfoFromExprList(
  Parse *pParse,       /* Parsing context */
  ExprList *pList,     /* Form the KeyInfo object from this ExprList */
  int iStart,          /* Begin with this column of pList */
  int nExtra           /* Add this many extra columns to the end */
){
  int nExpr;
  KeyInfo *pInfo;
  struct ExprList_item *pItem;
  sqlite3 *db = pParse->db;
  int i;

  nExpr = pList->nExpr;
  pInfo = sqlite3KeyInfoAlloc(db, nExpr+nExtra-iStart, 1);
  if( pInfo ){
    assert( sqlite3KeyInfoIsWriteable(pInfo) );
    for(i=iStart, pItem=pList->a+iStart; i<nExpr; i++, pItem++){
      CollSeq *pColl;
      pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
      if( !pColl ) pColl = db->pDfltColl;
      pInfo->aColl[i-iStart] = pColl;
      pInfo->aSortOrder[i-iStart] = pItem->sortOrder;
    }
  }
  return pInfo;
}

#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
................................................................................
** then the results were placed in a sorter.  After the loop is terminated
** we need to run the sorter and output the results.  The following
** routine generates the code needed to do that.
*/
static void generateSortTail(
  Parse *pParse,    /* Parsing context */
  Select *p,        /* The SELECT statement */
  SortCtx *pSort,   /* Information on the ORDER BY clause */
  int nColumn,      /* Number of columns of data */
  SelectDest *pDest /* Write the sorted results here */
){
  Vdbe *v = pParse->pVdbe;                     /* The prepared statement */
  int addrBreak = sqlite3VdbeMakeLabel(v);     /* Jump here to exit loop */
  int addrContinue = sqlite3VdbeMakeLabel(v);  /* Jump here for next cycle */
  int addr;
  int addrOnce = 0;
  int iTab;
  int pseudoTab = 0;
  ExprList *pOrderBy = pSort->pOrderBy;

  int eDest = pDest->eDest;
  int iParm = pDest->iSDParm;

  int regRow;
  int regRowid;
  int nKey;

  if( pSort->labelBkOut ){
    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrBreak);
    sqlite3VdbeResolveLabel(v, pSort->labelBkOut);
    addrOnce = sqlite3CodeOnce(pParse); VdbeCoverage(v);
  }
  iTab = pSort->iECursor;
  regRow = sqlite3GetTempReg(pParse);
  if( eDest==SRT_Output || eDest==SRT_Coroutine ){
    pseudoTab = pParse->nTab++;
    sqlite3VdbeAddOp3(v, OP_OpenPseudo, pseudoTab, regRow, nColumn);
    regRowid = 0;
  }else{
    regRowid = sqlite3GetTempReg(pParse);
  }
  nKey = pOrderBy->nExpr - pSort->nOBSat;
  if( pSort->sortFlags & SORTFLAG_UseSorter ){
    int regSortOut = ++pParse->nMem;
    int ptab2 = pParse->nTab++;
    sqlite3VdbeAddOp3(v, OP_OpenPseudo, ptab2, regSortOut, nKey+2);
    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
    VdbeCoverage(v);
    codeOffset(v, p->iOffset, addrContinue);
    sqlite3VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
    sqlite3VdbeAddOp3(v, OP_Column, ptab2, nKey+1, regRow);
    sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
  }else{
    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
    addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak); VdbeCoverage(v);
    codeOffset(v, p->iOffset, addrContinue);
    sqlite3VdbeAddOp3(v, OP_Column, iTab, nKey+1, regRow);
  }
  switch( eDest ){
    case SRT_Table:
    case SRT_EphemTab: {
      testcase( eDest==SRT_Table );
      testcase( eDest==SRT_EphemTab );
      sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
................................................................................
  }
  sqlite3ReleaseTempReg(pParse, regRow);
  sqlite3ReleaseTempReg(pParse, regRowid);

  /* The bottom of the loop
  */
  sqlite3VdbeResolveLabel(v, addrContinue);
  if( pSort->sortFlags & SORTFLAG_UseSorter ){
    sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr); VdbeCoverage(v);
  }else{
    sqlite3VdbeAddOp2(v, OP_Next, iTab, addr); VdbeCoverage(v);
  }
  if( pSort->regReturn ) sqlite3VdbeAddOp1(v, OP_Return, pSort->regReturn);
  sqlite3VdbeResolveLabel(v, addrBreak);
  if( eDest==SRT_Output || eDest==SRT_Coroutine ){
    sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
  }
}

/*
................................................................................
      Expr *pE = pFunc->pExpr;
      assert( !ExprHasProperty(pE, EP_xIsSelect) );
      if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
        sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
           "argument");
        pFunc->iDistinct = -1;
      }else{
        KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList, 0, 0);
        sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
                          (char*)pKeyInfo, P4_KEYINFO);
      }
    }
  }
}

................................................................................
  int i, j;              /* Loop counters */
  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
  Vdbe *v;               /* The virtual machine under construction */
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */

  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int rc = 1;            /* Value to return from this function */

  DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */
  SortCtx sSort;         /* Info on how to code the ORDER BY clause */
  AggInfo sAggInfo;      /* Information used by aggregate queries */
  int iEnd;              /* Address of the end of the query */
  sqlite3 *db;           /* The database connection */

#ifndef SQLITE_OMIT_EXPLAIN
  int iRestoreSelectId = pParse->iSelectId;
  pParse->iSelectId = pParse->iNextSelectId++;
................................................................................
    /* If ORDER BY makes no difference in the output then neither does
    ** DISTINCT so it can be removed too. */
    sqlite3ExprListDelete(db, p->pOrderBy);
    p->pOrderBy = 0;
    p->selFlags &= ~SF_Distinct;
  }
  sqlite3SelectPrep(pParse, p, 0);
  memset(&sSort, 0, sizeof(sSort));
  sSort.pOrderBy = p->pOrderBy;
  pTabList = p->pSrc;
  pEList = p->pEList;
  if( pParse->nErr || db->mallocFailed ){
    goto select_end;
  }
  isAgg = (p->selFlags & SF_Aggregate)!=0;
  assert( pEList!=0 );
................................................................................
    }
    if( /*pParse->nErr ||*/ db->mallocFailed ){
      goto select_end;
    }
    pParse->nHeight -= sqlite3SelectExprHeight(p);
    pTabList = p->pSrc;
    if( !IgnorableOrderby(pDest) ){
      sSort.pOrderBy = p->pOrderBy;
    }
  }
  pEList = p->pEList;
#endif
  pWhere = p->pWhere;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
................................................................................
  /* If there is both a GROUP BY and an ORDER BY clause and they are
  ** identical, then disable the ORDER BY clause since the GROUP BY
  ** will cause elements to come out in the correct order.  This is
  ** an optimization - the correct answer should result regardless.
  ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER
  ** to disable this optimization for testing purposes.
  */
  if( sqlite3ExprListCompare(p->pGroupBy, sSort.pOrderBy, -1)==0
         && OptimizationEnabled(db, SQLITE_GroupByOrder) ){
    sSort.pOrderBy = 0;
  }

  /* If the query is DISTINCT with an ORDER BY but is not an aggregate, and 
  ** if the select-list is the same as the ORDER BY list, then this query
  ** can be rewritten as a GROUP BY. In other words, this:
  **
  **     SELECT DISTINCT xyz FROM ... ORDER BY xyz
................................................................................
  **
  ** The second form is preferred as a single index (or temp-table) may be 
  ** used for both the ORDER BY and DISTINCT processing. As originally 
  ** written the query must use a temp-table for at least one of the ORDER 
  ** BY and DISTINCT, and an index or separate temp-table for the other.
  */
  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct 
   && sqlite3ExprListCompare(sSort.pOrderBy, p->pEList, -1)==0
  ){
    p->selFlags &= ~SF_Distinct;
    p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
    pGroupBy = p->pGroupBy;
    sSort.pOrderBy = 0;
    /* Notice that even thought SF_Distinct has been cleared from p->selFlags,
    ** the sDistinct.isTnct is still set.  Hence, isTnct represents the
    ** original setting of the SF_Distinct flag, not the current setting */
    assert( sDistinct.isTnct );
  }

  /* If there is an ORDER BY clause, then this sorting
  ** index might end up being unused if the data can be 
  ** extracted in pre-sorted order.  If that is the case, then the
  ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
  ** we figure out that the sorting index is not needed.  The addrSortIndex
  ** variable is used to facilitate that change.
  */
  if( sSort.pOrderBy ){
    KeyInfo *pKeyInfo;
    pKeyInfo = keyInfoFromExprList(pParse, sSort.pOrderBy, 0, 0);
    sSort.iECursor = pParse->nTab++;
    sSort.addrSortIndex =
      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
                           sSort.iECursor, sSort.pOrderBy->nExpr+2, 0,
                           (char*)pKeyInfo, P4_KEYINFO);
  }else{
    sSort.addrSortIndex = -1;
  }

  /* If the output is destined for a temporary table, open that table.
  */
  if( pDest->eDest==SRT_EphemTab ){
    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr);
  }

  /* Set the limiter.
  */
  iEnd = sqlite3VdbeMakeLabel(v);
  p->nSelectRow = LARGEST_INT64;
  computeLimitRegisters(pParse, p, iEnd);
  if( p->iLimit==0 && sSort.addrSortIndex>=0 ){
    sqlite3VdbeGetOp(v, sSort.addrSortIndex)->opcode = OP_SorterOpen;
    sSort.sortFlags |= SORTFLAG_UseSorter;
  }

  /* Open a virtual index to use for the distinct set.
  */
  if( p->selFlags & SF_Distinct ){
    sDistinct.tabTnct = pParse->nTab++;
    sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
                                sDistinct.tabTnct, 0, 0,
                                (char*)keyInfoFromExprList(pParse, p->pEList,0,0),
                                P4_KEYINFO);
    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
    sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED;
  }else{
    sDistinct.eTnctType = WHERE_DISTINCT_NOOP;
  }

  if( !isAgg && pGroupBy==0 ){
    /* No aggregate functions and no GROUP BY clause */
    u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0);

    /* Begin the database scan. */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, sSort.pOrderBy,
                               p->pEList, wctrlFlags, 0);
    if( pWInfo==0 ) goto select_end;
    if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
      p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
    }
    if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){
      sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo);
    }
    if( sSort.pOrderBy ){
      sSort.nOBSat = sqlite3WhereIsOrdered(pWInfo);
      if( sSort.nOBSat==sSort.pOrderBy->nExpr ){
        sSort.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( sSort.addrSortIndex>=0 && sSort.pOrderBy==0 ){
      sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex);

    }

    /* Use the standard inner loop. */
    selectInnerLoop(pParse, p, pEList, -1, &sSort, &sDistinct, pDest,
                    sqlite3WhereContinueLabel(pWInfo),
                    sqlite3WhereBreakLabel(pWInfo));

    /* End the database scan loop.
    */
    sqlite3WhereEnd(pWInfo);
  }else{
................................................................................
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;
    sNC.pAggInfo = &sAggInfo;
    sAggInfo.mnReg = pParse->nMem+1;
    sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
    sAggInfo.pGroupBy = pGroupBy;
    sqlite3ExprAnalyzeAggList(&sNC, pEList);
    sqlite3ExprAnalyzeAggList(&sNC, sSort.pOrderBy);
    if( pHaving ){
      sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
    }
    sAggInfo.nAccumulator = sAggInfo.nColumn;
    for(i=0; i<sAggInfo.nFunc; i++){
      assert( !ExprHasProperty(sAggInfo.aFunc[i].pExpr, EP_xIsSelect) );
      sNC.ncFlags |= NC_InAggFunc;
................................................................................

      /* If there is a GROUP BY clause we might need a sorting index to
      ** implement it.  Allocate that sorting index now.  If it turns out
      ** that we do not need it after all, the OP_SorterOpen instruction
      ** will be converted into a Noop.  
      */
      sAggInfo.sortingIdx = pParse->nTab++;
      pKeyInfo = keyInfoFromExprList(pParse, pGroupBy, 0, 0);
      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen, 
          sAggInfo.sortingIdx, sAggInfo.nSortingColumn, 
          0, (char*)pKeyInfo, P4_KEYINFO);

      /* Initialize memory locations used by GROUP BY aggregate processing
      */
      iUseFlag = ++pParse->nMem;
................................................................................

      /* 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.
      */
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, 0,
                                 WHERE_GROUPBY, 0);
      if( pWInfo==0 ) goto select_end;
      if( sqlite3WhereIsOrdered(pWInfo)==pGroupBy->nExpr ){
        /* 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;
      }else{
        /* Rows are coming out in undetermined order.  We have to push
................................................................................
      sqlite3VdbeResolveLabel(v, addrOutputRow);
      addrOutputRow = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2); VdbeCoverage(v);
      VdbeComment((v, "Groupby result generator entry point"));
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      finalizeAggFunctions(pParse, &sAggInfo);
      sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
      selectInnerLoop(pParse, p, p->pEList, -1, &sSort,
                      &sDistinct, pDest,
                      addrOutputRow+1, addrSetAbort);
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      VdbeComment((v, "end groupby result generator"));

      /* Generate a subroutine that will reset the group-by accumulator
      */
................................................................................
        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMax,0,flag,0);
        if( pWInfo==0 ){
          sqlite3ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        assert( pMinMax==0 || pMinMax->nExpr==1 );
        if( sqlite3WhereIsOrdered(pWInfo)>0 ){
          sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3WhereBreakLabel(pWInfo));
          VdbeComment((v, "%s() by index",
                (flag==WHERE_ORDERBY_MIN?"min":"max")));
        }
        sqlite3WhereEnd(pWInfo);
        finalizeAggFunctions(pParse, &sAggInfo);
      }

      sSort.pOrderBy = 0;
      sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
      selectInnerLoop(pParse, p, p->pEList, -1, 0, 0, 
                      pDest, addrEnd, addrEnd);
      sqlite3ExprListDelete(db, pDel);
    }
    sqlite3VdbeResolveLabel(v, addrEnd);
    
................................................................................
  if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){
    explainTempTable(pParse, "DISTINCT");
  }

  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( sSort.pOrderBy ){
    explainTempTable(pParse, sSort.nOBSat>0 ? "RIGHT PART OF ORDER BY":"ORDER BY");
    generateSortTail(pParse, p, &sSort, pEList->nExpr, pDest);
  }

  /* Jump here to skip this query
  */
  sqlite3VdbeResolveLabel(v, iEnd);

  /* The SELECT was successfully coded.   Set the return code to 0

Changes to src/sqliteInt.h.

1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
....
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
....
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
** column expression as it exists in a SELECT statement.  However, if
** the bSpanIsTab flag is set, then zSpan is overloaded to mean the name
** of the result column in the form: DATABASE.TABLE.COLUMN.  This later
** form is used for name resolution with nested FROM clauses.
*/
struct ExprList {
  int nExpr;             /* Number of expressions on the list */
  int iECursor;          /* VDBE Cursor associated with this ExprList */
  struct ExprList_item { /* For each expression in the list */
    Expr *pExpr;            /* The list of expressions */
    char *zName;            /* Token associated with this expression */
    char *zSpan;            /* Original text of the expression */
    u8 sortOrder;           /* 1 for DESC or 0 for ASC */
    unsigned done :1;       /* A flag to indicate when processing is finished */
    unsigned bSpanIsTab :1; /* zSpan holds DB.TABLE.COLUMN */
................................................................................
** sequences for the ORDER BY clause.
*/
struct Select {
  ExprList *pEList;      /* The fields of the result */
  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  u16 selFlags;          /* Various SF_* values */
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
  u64 nSelectRow;        /* Estimated number of result rows */
  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
................................................................................
*/
#define SF_Distinct        0x0001  /* Output should be DISTINCT */
#define SF_Resolved        0x0002  /* Identifiers have been resolved */
#define SF_Aggregate       0x0004  /* Contains aggregate functions */
#define SF_UsesEphemeral   0x0008  /* Uses the OpenEphemeral opcode */
#define SF_Expanded        0x0010  /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */
#define SF_UseSorter       0x0040  /* Sort using a sorter */
#define SF_Values          0x0080  /* Synthesized from VALUES clause */
#define SF_Materialize     0x0100  /* NOT USED */
#define SF_NestedFrom      0x0200  /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert    0x0400  /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive       0x0800  /* The recursive part of a recursive CTE */
#define SF_Compound        0x1000  /* Part of a compound query */


/*







<







 







|







 







|

|







1954
1955
1956
1957
1958
1959
1960

1961
1962
1963
1964
1965
1966
1967
....
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
....
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
** column expression as it exists in a SELECT statement.  However, if
** the bSpanIsTab flag is set, then zSpan is overloaded to mean the name
** of the result column in the form: DATABASE.TABLE.COLUMN.  This later
** form is used for name resolution with nested FROM clauses.
*/
struct ExprList {
  int nExpr;             /* Number of expressions on the list */

  struct ExprList_item { /* For each expression in the list */
    Expr *pExpr;            /* The list of expressions */
    char *zName;            /* Token associated with this expression */
    char *zSpan;            /* Original text of the expression */
    u8 sortOrder;           /* 1 for DESC or 0 for ASC */
    unsigned done :1;       /* A flag to indicate when processing is finished */
    unsigned bSpanIsTab :1; /* zSpan holds DB.TABLE.COLUMN */
................................................................................
** sequences for the ORDER BY clause.
*/
struct Select {
  ExprList *pEList;      /* The fields of the result */
  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  u16 selFlags;          /* Various SF_* values */
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  int addrOpenEphm[2];   /* OP_OpenEphem opcodes related to this select */
  u64 nSelectRow;        /* Estimated number of result rows */
  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
................................................................................
*/
#define SF_Distinct        0x0001  /* Output should be DISTINCT */
#define SF_Resolved        0x0002  /* Identifiers have been resolved */
#define SF_Aggregate       0x0004  /* Contains aggregate functions */
#define SF_UsesEphemeral   0x0008  /* Uses the OpenEphemeral opcode */
#define SF_Expanded        0x0010  /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */
                    /*     0x0040  NOT USED */
#define SF_Values          0x0080  /* Synthesized from VALUES clause */
                    /*     0x0100  NOT USED */
#define SF_NestedFrom      0x0200  /* Part of a parenthesized FROM clause */
#define SF_MaybeConvert    0x0400  /* Need convertCompoundSelectToSubquery() */
#define SF_Recursive       0x0800  /* The recursive part of a recursive CTE */
#define SF_Compound        0x1000  /* Part of a compound query */


/*

Changes to src/vdbe.c.

1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086

1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
....
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
....
1991
1992
1993
1994
1995
1996
1997

1998
1999
2000
2001
2002
2003
2004
....
3326
3327
3328
3329
3330
3331
3332

3333
3334
3335
3336
3337
3338
3339
....
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
....
4864
4865
4866
4867
4868
4869
4870























4871
4872
4873
4874
4875
4876
4877
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Move P1 P2 P3 * *
** Synopsis:  r[P2@P3]=r[P1@P3]
**
** Move the values in register P1..P1+P3 over into
** registers P2..P2+P3.  Registers P1..P1+P3 are
** left holding a NULL.  It is an error for register ranges
** P1..P1+P3 and P2..P2+P3 to overlap.

*/
case OP_Move: {
  char *zMalloc;   /* Holding variable for allocated memory */
  int n;           /* Number of registers left to copy */
  int p1;          /* Register to copy from */
  int p2;          /* Register to copy to */

  n = pOp->p3;
  p1 = pOp->p1;
  p2 = pOp->p2;
  assert( n>=0 && p1>0 && p2>0 );
  assert( p1+n<=p2 || p2+n<=p1 );

  pIn1 = &aMem[p1];
  pOut = &aMem[p2];
  do{
    assert( pOut<=&aMem[(p->nMem-p->nCursor)] );
    assert( pIn1<=&aMem[(p->nMem-p->nCursor)] );
................................................................................
#endif
    pIn1->flags = MEM_Undefined;
    pIn1->xDel = 0;
    pIn1->zMalloc = zMalloc;
    REGISTER_TRACE(p2++, pOut);
    pIn1++;
    pOut++;
  }while( n-- );
  break;
}

/* Opcode: Copy P1 P2 P3 * *
** Synopsis: r[P2@P3+1]=r[P1@P3+1]
**
** Make a copy of registers P1..P1+P3 into registers P2..P2+P3.
................................................................................
  assert( pOp->p4type==P4_INTARRAY );
  assert( pOp->p4.ai );
  aPermute = pOp->p4.ai;
  break;
}

/* Opcode: Compare P1 P2 P3 P4 P5

**
** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
** the comparison for use by the next OP_Jump instruct.
**
** If P5 has the OPFLAG_PERMUTE bit set, then the order of comparison is
** determined by the most recent OP_Permutation operator.  If the
................................................................................
      SQLITE_OPEN_DELETEONCLOSE |
      SQLITE_OPEN_TRANSIENT_DB;
  assert( pOp->p1>=0 );
  assert( pOp->p2>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, 1);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;

  rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->pBt, 
                        BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5, vfsFlags);
  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1);
  }
  if( rc==SQLITE_OK ){
    /* If a transient index is required, create it by calling
................................................................................
    assert( pC->rowidIsValid==0 );
  }
  pC->seekResult = res;
  break;
}

/* Opcode: Sequence P1 P2 * * *
** Synopsis: r[P2]=rowid
**
** Find the next available sequence number for cursor P1.
** Write the sequence number into register P2.
** The sequence number on the cursor is incremented after this
** instruction.  
*/
case OP_Sequence: {           /* out2-prerelease */
................................................................................
      assert( memIsValid(&aMem[pOp->p3]) );
      memAboutToChange(p, &aMem[pOp->p3]);
      aMem[pOp->p3].u.i += nChange;
    }
  }
  break;
}
























/* Opcode: CreateTable P1 P2 * * *
** Synopsis: r[P2]=root iDb=P1
**
** Allocate a new table in the main database file if P1==0 or in the
** auxiliary database file if P1==1 or in an attached database if
** P1>1.  Write the root page number of the new table into







|
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>







 







>







 







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







1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
....
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
....
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
....
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
....
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
....
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
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Move P1 P2 P3 * *
** Synopsis:  r[P2@P3]=r[P1@P3]
**
** Move the P3 values in register P1..P1+P3-1 over into
** registers P2..P2+P3-1.  Registers P1..P1+P3-1 are
** left holding a NULL.  It is an error for register ranges
** P1..P1+P3-1 and P2..P2+P3-1 to overlap.  It is an error
** for P3 to be less than 1.
*/
case OP_Move: {
  char *zMalloc;   /* Holding variable for allocated memory */
  int n;           /* Number of registers left to copy */
  int p1;          /* Register to copy from */
  int p2;          /* Register to copy to */

  n = pOp->p3;
  p1 = pOp->p1;
  p2 = pOp->p2;
  assert( n>0 && p1>0 && p2>0 );
  assert( p1+n<=p2 || p2+n<=p1 );

  pIn1 = &aMem[p1];
  pOut = &aMem[p2];
  do{
    assert( pOut<=&aMem[(p->nMem-p->nCursor)] );
    assert( pIn1<=&aMem[(p->nMem-p->nCursor)] );
................................................................................
#endif
    pIn1->flags = MEM_Undefined;
    pIn1->xDel = 0;
    pIn1->zMalloc = zMalloc;
    REGISTER_TRACE(p2++, pOut);
    pIn1++;
    pOut++;
  }while( --n );
  break;
}

/* Opcode: Copy P1 P2 P3 * *
** Synopsis: r[P2@P3+1]=r[P1@P3+1]
**
** Make a copy of registers P1..P1+P3 into registers P2..P2+P3.
................................................................................
  assert( pOp->p4type==P4_INTARRAY );
  assert( pOp->p4.ai );
  aPermute = pOp->p4.ai;
  break;
}

/* Opcode: Compare P1 P2 P3 P4 P5
** Synopsis: r[P1@P3] <-> r[P2@P3]
**
** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
** the comparison for use by the next OP_Jump instruct.
**
** If P5 has the OPFLAG_PERMUTE bit set, then the order of comparison is
** determined by the most recent OP_Permutation operator.  If the
................................................................................
      SQLITE_OPEN_DELETEONCLOSE |
      SQLITE_OPEN_TRANSIENT_DB;
  assert( pOp->p1>=0 );
  assert( pOp->p2>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p2, -1, 1);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->isEphemeral = 1;
  rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->pBt, 
                        BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5, vfsFlags);
  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1);
  }
  if( rc==SQLITE_OK ){
    /* If a transient index is required, create it by calling
................................................................................
    assert( pC->rowidIsValid==0 );
  }
  pC->seekResult = res;
  break;
}

/* Opcode: Sequence P1 P2 * * *
** Synopsis: r[P2]=cursor[P1].ctr++
**
** Find the next available sequence number for cursor P1.
** Write the sequence number into register P2.
** The sequence number on the cursor is incremented after this
** instruction.  
*/
case OP_Sequence: {           /* out2-prerelease */
................................................................................
      assert( memIsValid(&aMem[pOp->p3]) );
      memAboutToChange(p, &aMem[pOp->p3]);
      aMem[pOp->p3].u.i += nChange;
    }
  }
  break;
}

/* Opcode: ResetSorter P1 * * * *
**
** Delete all contents from the ephemeral table or sorter
** that is open on cursor P1.
**
** This opcode only works for cursors used for sorting and
** opened with OP_OpenEphemeral or OP_SorterOpen.
*/
case OP_ResetSorter: {
  VdbeCursor *pC;
 
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  if( pC->pSorter ){
    sqlite3VdbeSorterReset(db, pC->pSorter);
  }else{
    assert( pC->isEphemeral );
    rc = sqlite3BtreeClearTableOfCursor(pC->pCursor);
  }
  break;
}

/* Opcode: CreateTable P1 P2 * * *
** Synopsis: r[P2]=root iDb=P1
**
** Allocate a new table in the main database file if P1==0 or in the
** auxiliary database file if P1==1 or in an attached database if
** P1>1.  Write the root page number of the new table into

Changes to src/vdbeInt.h.

68
69
70
71
72
73
74

75
76
77
78
79
80
81
...
433
434
435
436
437
438
439

440
441
442
443
444
445
446
  int pseudoTableReg;   /* Register holding pseudotable content. */
  i16 nField;           /* Number of fields in the header */
  u16 nHdrParsed;       /* Number of header fields parsed so far */
  i8 iDb;               /* Index of cursor database in db->aDb[] (or -1) */
  u8 nullRow;           /* True if pointing to a row with no data */
  u8 rowidIsValid;      /* True if lastRowid is valid */
  u8 deferredMoveto;    /* A call to sqlite3BtreeMoveto() is needed */

  Bool useRandomRowid:1;/* Generate new record numbers semi-randomly */
  Bool isTable:1;       /* True if a table requiring integer keys */
  Bool isOrdered:1;     /* True if the underlying table is BTREE_UNORDERED */
  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
  i64 lastRowid;        /* Rowid being deleted by OP_Delete */
................................................................................
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
int sqlite3VdbeTransferError(Vdbe *p);

int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);

void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);
int sqlite3VdbeSorterNext(sqlite3 *, const VdbeCursor *, int *);
int sqlite3VdbeSorterRewind(sqlite3 *, const VdbeCursor *, int *);
int sqlite3VdbeSorterWrite(sqlite3 *, const VdbeCursor *, Mem *);
int sqlite3VdbeSorterCompare(const VdbeCursor *, Mem *, int, int *);








>







 







>







68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
...
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
  int pseudoTableReg;   /* Register holding pseudotable content. */
  i16 nField;           /* Number of fields in the header */
  u16 nHdrParsed;       /* Number of header fields parsed so far */
  i8 iDb;               /* Index of cursor database in db->aDb[] (or -1) */
  u8 nullRow;           /* True if pointing to a row with no data */
  u8 rowidIsValid;      /* True if lastRowid is valid */
  u8 deferredMoveto;    /* A call to sqlite3BtreeMoveto() is needed */
  Bool isEphemeral:1;   /* True for an ephemeral table */
  Bool useRandomRowid:1;/* Generate new record numbers semi-randomly */
  Bool isTable:1;       /* True if a table requiring integer keys */
  Bool isOrdered:1;     /* True if the underlying table is BTREE_UNORDERED */
  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */
  i64 seqCount;         /* Sequence counter */
  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
  i64 lastRowid;        /* Rowid being deleted by OP_Delete */
................................................................................
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
int sqlite3VdbeTransferError(Vdbe *p);

int sqlite3VdbeSorterInit(sqlite3 *, VdbeCursor *);
void sqlite3VdbeSorterReset(sqlite3 *, VdbeSorter *);
void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);
int sqlite3VdbeSorterNext(sqlite3 *, const VdbeCursor *, int *);
int sqlite3VdbeSorterRewind(sqlite3 *, const VdbeCursor *, int *);
int sqlite3VdbeSorterWrite(sqlite3 *, const VdbeCursor *, Mem *);
int sqlite3VdbeSorterCompare(const VdbeCursor *, Mem *, int, int *);

Changes to src/vdbeaux.c.

779
780
781
782
783
784
785
786


787
788
789
790
791
792
793
  }
  assert( p->nOp>0 );
  assert( addr<p->nOp );
  if( addr<0 ){
    addr = p->nOp - 1;
  }
  pOp = &p->aOp[addr];
  assert( pOp->p4type==P4_NOTUSED || pOp->p4type==P4_INT32 );


  freeP4(db, pOp->p4type, pOp->p4.p);
  pOp->p4.p = 0;
  if( n==P4_INT32 ){
    /* Note: this cast is safe, because the origin data point was an int
    ** that was cast to a (const char *). */
    pOp->p4.i = SQLITE_PTR_TO_INT(zP4);
    pOp->p4type = P4_INT32;







|
>
>







779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
  }
  assert( p->nOp>0 );
  assert( addr<p->nOp );
  if( addr<0 ){
    addr = p->nOp - 1;
  }
  pOp = &p->aOp[addr];
  assert( pOp->p4type==P4_NOTUSED
       || pOp->p4type==P4_INT32
       || pOp->p4type==P4_KEYINFO );
  freeP4(db, pOp->p4type, pOp->p4.p);
  pOp->p4.p = 0;
  if( n==P4_INT32 ){
    /* Note: this cast is safe, because the origin data point was an int
    ** that was cast to a (const char *). */
    pOp->p4.i = SQLITE_PTR_TO_INT(zP4);
    pOp->p4type = P4_INT32;

Changes to src/vdbesort.c.

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
  SorterRecord *p;
  SorterRecord *pNext;
  for(p=pRecord; p; p=pNext){
    pNext = p->pNext;
    sqlite3DbFree(db, p);
  }
}




























/*
** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
*/
void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
  VdbeSorter *pSorter = pCsr->pSorter;
  if( pSorter ){
    if( pSorter->aIter ){
      int i;
      for(i=0; i<pSorter->nTree; i++){
        vdbeSorterIterZero(db, &pSorter->aIter[i]);
      }
      sqlite3DbFree(db, pSorter->aIter);
    }
    if( pSorter->pTemp1 ){
      sqlite3OsCloseFree(pSorter->pTemp1);
    }
    vdbeSorterRecordFree(db, pSorter->pRecord);
    sqlite3DbFree(db, pSorter->pUnpacked);
    sqlite3DbFree(db, pSorter);
    pCsr->pSorter = 0;
  }
}

/*







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







|
<
<
<
<
<
<
<
<
<
<







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
533
534
535
536
537
538
539
540










541
542
543
544
545
546
547
  SorterRecord *p;
  SorterRecord *pNext;
  for(p=pRecord; p; p=pNext){
    pNext = p->pNext;
    sqlite3DbFree(db, p);
  }
}

/*
** Reset a sorting cursor back to its original empty state.
*/
void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){
  if( pSorter->aIter ){
    int i;
    for(i=0; i<pSorter->nTree; i++){
      vdbeSorterIterZero(db, &pSorter->aIter[i]);
    }
    sqlite3DbFree(db, pSorter->aIter);
    pSorter->aIter = 0;
  }
  if( pSorter->pTemp1 ){
    sqlite3OsCloseFree(pSorter->pTemp1);
    pSorter->pTemp1 = 0;
  }
  vdbeSorterRecordFree(db, pSorter->pRecord);
  pSorter->pRecord = 0;
  pSorter->iWriteOff = 0;
  pSorter->iReadOff = 0;
  pSorter->nInMemory = 0;
  pSorter->nTree = 0;
  pSorter->nPMA = 0;
  pSorter->aTree = 0;
}


/*
** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
*/
void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
  VdbeSorter *pSorter = pCsr->pSorter;
  if( pSorter ){
    sqlite3VdbeSorterReset(db, pSorter);










    sqlite3DbFree(db, pSorter->pUnpacked);
    sqlite3DbFree(db, pSorter);
    pCsr->pSorter = 0;
  }
}

/*

Changes to src/where.c.

35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
....
3033
3034
3035
3036
3037
3038
3039



3040
3041
3042
3043
3044
3045
3046
3047
3048
....
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
....
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
....
4913
4914
4915
4916
4917
4918
4919
4920
4921






4922
4923
4924
4925
4926
4927
4928
....
4951
4952
4953
4954
4955
4956
4957

4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
....
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
....
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
....
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
....
5189
5190
5191
5192
5193
5194
5195

5196
5197
5198


5199

5200

5201
5202


5203
5204
5205
5206
5207
5208
5209
....
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
....
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
....
5406
5407
5408
5409
5410
5411
5412




5413
5414
5415
5416
5417
5418
5419
....
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
....
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
}

/*
** Return TRUE if the WHERE clause returns rows in ORDER BY order.
** Return FALSE if the output needs to be sorted.
*/
int sqlite3WhereIsOrdered(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 sqlite3WhereContinueLabel(WhereInfo *pWInfo){
................................................................................
    ** 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->nKeyCol>nEq)
    ){
      assert( pLoop->u.btree.nSkip==0 );
      bSeekPastNull = 1;
      nExtraReg = 1;
    }

................................................................................
    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 = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
      pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
      whereLoopInsert(pBuilder, pNew);
      if( pNew->u.vtab.needFree ){
        sqlite3_free(pNew->u.vtab.idxStr);
        pNew->u.vtab.needFree = 0;
................................................................................
  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 */
................................................................................
        if( mTerm==0 && !sqlite3ExprIsConstant(p) ) continue;
        if( (mTerm&~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 mxChoice;             /* Maximum number of simultaneous paths tracked */
  int nLoop;                /* Number of terms in the join */
  Parse *pParse;            /* Parsing context */
  sqlite3 *db;              /* The database connection */
  int iLoop;                /* Loop counter over the terms of the join */
  int ii, jj;               /* Loop counters */
  int mxI = 0;              /* Index of next entry to replace */

  LogEst rCost;             /* Cost of a path */
  LogEst nOut;              /* Number of outputs */
  LogEst mxCost = 0;        /* Maximum cost of a set of paths */
  LogEst mxOut = 0;         /* Maximum nOut value on the set of paths */
  LogEst 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 */
................................................................................
  ** 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==sqlite3LogEst(25) );
  nFrom = 1;

  /* Precompute the cost of sorting the final result set, if the caller
  ** to sqlite3WhereBegin() was concerned about sorting */
  rSortCost = 0;
  if( pWInfo->pOrderBy==0 || nRowEst==0 ){
    aFrom[0].isOrderedValid = 1;

  }else{
    /* TUNING: Estimated cost of sorting is 48*N*log2(N) where N is the
    ** number of output rows. The 48 is the expected size of a row to sort. 
    ** FIXME:  compute a better estimate of the 48 multiplier based on the
    ** result set expressions. */
    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 = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
        rCost = sqlite3LogEstAdd(rCost, pFrom->rCost);
        nOut = pFrom->nRow + pWLoop->nOut;
        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 = sqlite3LogEstAdd(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
           && ((pTo->rCost<=rCost && pTo->nRow<=nOut) ||
                (pTo->rCost>=rCost && pTo->nRow>=nOut))
          ){
            testcase( jj==nTo-1 );
            break;
          }
        }
        if( jj>=nTo ){
          if( nTo>=mxChoice && rCost>=mxCost ){
#ifdef WHERETRACE_ENABLED /* 0x4 */
            if( sqlite3WhereTrace&0x4 ){
              sqlite3DebugPrintf("Skip   %s cost=%-3d,%3d order=%c\n",
                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                  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 = mxI;
          }
          pTo = &aTo[jj];
#ifdef WHERETRACE_ENABLED /* 0x4 */
          if( sqlite3WhereTrace&0x4 ){
            sqlite3DebugPrintf("New    %s cost=%-3d,%3d order=%c\n",
                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
          }
#endif
        }else{
          if( pTo->rCost<=rCost && pTo->nRow<=nOut ){
#ifdef WHERETRACE_ENABLED /* 0x4 */
            if( sqlite3WhereTrace&0x4 ){
              sqlite3DebugPrintf(
                  "Skip   %s cost=%-3d,%3d order=%c",
                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                  isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
              sqlite3DebugPrintf("   vs %s cost=%-3d,%d order=%c\n",
                  wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
                  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 /* 0x4 */
          if( sqlite3WhereTrace&0x4 ){
            sqlite3DebugPrintf(
                "Update %s cost=%-3d,%3d order=%c",
                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
            sqlite3DebugPrintf("  was %s cost=%-3d,%3d order=%c\n",
                wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
                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 = 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 ){
          mxI = 0;
          mxCost = aTo[0].rCost;
          mxOut = aTo[0].nRow;
................................................................................

#ifdef WHERETRACE_ENABLED  /* >=2 */
    if( sqlite3WhereTrace>=2 ){
      sqlite3DebugPrintf("---- after round %d ----\n", iLoop);
      for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
        sqlite3DebugPrintf(" %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 ){
          sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
        }else{
          sqlite3DebugPrintf("\n");
        }
      }
    }
#endif
................................................................................
   && (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 */
  sqlite3DbFree(db, pSpace);
................................................................................
  }
  if( pLoop->wsFlags ){
    pLoop->nOut = (LogEst)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 SQLITE_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
................................................................................
** be used to compute the appropriate cursor depending on which index is
** used.
*/
WhereInfo *sqlite3WhereBegin(
  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 */
................................................................................
  sqlite3 *db;               /* Database connection */
  int rc;                    /* Return code */


  /* Variable initialization */
  db = pParse->db;
  memset(&sWLB, 0, sizeof(sWLB));




  sWLB.pOrderBy = pOrderBy;

  /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
  ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
  if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
    wctrlFlags &= ~WHERE_WANT_DISTINCT;
  }
................................................................................
      sWLB.pWC->a[ii].wtFlags |= TERM_CODED;
    }
  }

  /* 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.
  **
................................................................................
  if( pParse->nErr || NEVER(db->mallocFailed) ){
    goto whereBeginError;
  }
#ifdef WHERETRACE_ENABLED /* !=0 */
  if( sqlite3WhereTrace ){
    int ii;
    sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
    if( pWInfo->bOBSat ){
      sqlite3DebugPrintf(" ORDERBY=0x%llx", pWInfo->revMask);
    }
    switch( pWInfo->eDistinct ){
      case WHERE_DISTINCT_UNIQUE: {
        sqlite3DebugPrintf("  DISTINCT=unique");
        break;
      }
      case WHERE_DISTINCT_ORDERED: {







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43
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45
46
47
48
49
....
3033
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3037
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3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
....
4507
4508
4509
4510
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4512
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4514
4515
4516
4517
4518
4519
4520
4521
4522
....
4669
4670
4671
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4673
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4680
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4682
4683
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4685
4686
4687
4688
4689
4690
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4693
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4697
....
4916
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....
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4971

4972
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....
5006
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5010
5011
5012

5013
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5018




5019
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5060
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....
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5137
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....
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....
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....
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....
5398
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....
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....
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....
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5628
}

/*
** Return TRUE if the WHERE clause returns rows in ORDER BY order.
** Return FALSE if the output needs to be sorted.
*/
int sqlite3WhereIsOrdered(WhereInfo *pWInfo){
  return pWInfo->nOBSat;
}

/*
** Return the VDBE address or label to jump to in order to continue
** immediately with the next row of a WHERE clause.
*/
int sqlite3WhereContinueLabel(WhereInfo *pWInfo){
................................................................................
    ** 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.
    */
    assert( pWInfo->pOrderBy==0
         || pWInfo->pOrderBy->nExpr==1
         || (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 );
    if( (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)!=0
     && pWInfo->nOBSat>0
     && (pIdx->nKeyCol>nEq)
    ){
      assert( pLoop->u.btree.nSkip==0 );
      bSeekPastNull = 1;
      nExtraReg = 1;
    }

................................................................................
    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 = (i8)(pIdxInfo->orderByConsumed ?
                                      pIdxInfo->nOrderBy : 0);
      pNew->rSetup = 0;
      pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
      pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
      whereLoopInsert(pBuilder, pNew);
      if( pNew->u.vtab.needFree ){
        sqlite3_free(pNew->u.vtab.idxStr);
        pNew->u.vtab.needFree = 0;
................................................................................
  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 N:
** 
**   N>0:   N terms of the ORDER BY clause are satisfied
**   N==0:  No terms of the ORDER BY clause are satisfied
**   N<0:   Unknown yet how many terms of ORDER BY might be satisfied.   
**
** 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 i8 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 */
................................................................................
        if( mTerm==0 && !sqlite3ExprIsConstant(p) ) continue;
        if( (mTerm&~orderDistinctMask)==0 ){
          obSat |= MASKBIT(i);
        }
      }
    }
  } /* End the loop over all WhereLoops from outer-most down to inner-most */
  if( obSat==obDone ) return nOrderBy;
  if( !isOrderDistinct ){
    for(i=nOrderBy-1; i>0; i--){
      Bitmask m = MASKBIT(i) - 1;
      if( (obSat&m)==m ) return i;
    }
    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 mxChoice;             /* Maximum number of simultaneous paths tracked */
  int nLoop;                /* Number of terms in the join */
  Parse *pParse;            /* Parsing context */
  sqlite3 *db;              /* The database connection */
  int iLoop;                /* Loop counter over the terms of the join */
  int ii, jj;               /* Loop counters */
  int mxI = 0;              /* Index of next entry to replace */
  int nOrderBy;             /* Number of ORDER BY clause terms */
  LogEst rCost;             /* Cost of a path */
  LogEst nOut;              /* Number of outputs */
  LogEst mxCost = 0;        /* Maximum cost of a set of paths */
  LogEst mxOut = 0;         /* Maximum nOut value on the set of paths */

  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 */
................................................................................
  ** 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==sqlite3LogEst(25) );
  nFrom = 1;

  /* Precompute the cost of sorting the final result set, if the caller
  ** to sqlite3WhereBegin() was concerned about sorting */

  if( pWInfo->pOrderBy==0 || nRowEst==0 ){
    aFrom[0].isOrdered = 0;
    nOrderBy = 0;
  }else{
    aFrom[0].isOrdered = -1;
    nOrderBy = pWInfo->pOrderBy->nExpr;




  }

  /* 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;

        i8 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 = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
        rCost = sqlite3LogEstAdd(rCost, pFrom->rCost);
        nOut = pFrom->nRow + pWLoop->nOut;
        maskNew = pFrom->maskLoop | pWLoop->maskSelf;
        if( isOrdered<0 ){
          isOrdered = wherePathSatisfiesOrderBy(pWInfo,
                       pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
                       iLoop, pWLoop, &revMask);
          if( isOrdered>=0 && isOrdered<nOrderBy ){
            /* TUNING: Estimated cost of sorting cost as roughly N*log(N).
            ** If some but not all of the columns are in sorted order, then
            ** scale down the log(N) term. */
            LogEst rScale = sqlite3LogEst((nOrderBy-isOrdered)*100/nOrderBy);
            LogEst rSortCost = nRowEst + estLog(nRowEst) + rScale - 66;
            /* TUNING: The cost of implementing DISTINCT using a B-TREE is
            ** also N*log(N) but it has a larger constant of proportionality.
            ** Multiply by 3.0. */
            if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
              rSortCost += 16;
            }
            WHERETRACE(0x002,
               ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
                rSortCost, (nOrderBy-isOrdered), nOrderBy, rCost,
                sqlite3LogEstAdd(rCost,rSortCost)));
            rCost = sqlite3LogEstAdd(rCost, rSortCost);



          }
        }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->isOrdered^isOrdered)&80)==0
           && ((pTo->rCost<=rCost && pTo->nRow<=nOut) ||
                (pTo->rCost>=rCost && pTo->nRow>=nOut))
          ){
            testcase( jj==nTo-1 );
            break;
          }
        }
        if( jj>=nTo ){
          if( nTo>=mxChoice && rCost>=mxCost ){
#ifdef WHERETRACE_ENABLED /* 0x4 */
            if( sqlite3WhereTrace&0x4 ){
              sqlite3DebugPrintf("Skip   %s cost=%-3d,%3d order=%c\n",
                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                  isOrdered>=0 ? isOrdered+'0' : '?');
            }
#endif
            continue;
          }
          /* Add a new Path to the aTo[] set */
          if( nTo<mxChoice ){
            /* Increase the size of the aTo set by one */
................................................................................
            jj = mxI;
          }
          pTo = &aTo[jj];
#ifdef WHERETRACE_ENABLED /* 0x4 */
          if( sqlite3WhereTrace&0x4 ){
            sqlite3DebugPrintf("New    %s cost=%-3d,%3d order=%c\n",
                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                isOrdered>=0 ? isOrdered+'0' : '?');
          }
#endif
        }else{
          if( pTo->rCost<=rCost && pTo->nRow<=nOut ){
#ifdef WHERETRACE_ENABLED /* 0x4 */
            if( sqlite3WhereTrace&0x4 ){
              sqlite3DebugPrintf(
                  "Skip   %s cost=%-3d,%3d order=%c",
                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                  isOrdered>=0 ? isOrdered+'0' : '?');
              sqlite3DebugPrintf("   vs %s cost=%-3d,%d order=%c\n",
                  wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
                  pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
            }
#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 /* 0x4 */
          if( sqlite3WhereTrace&0x4 ){
            sqlite3DebugPrintf(
                "Update %s cost=%-3d,%3d order=%c",
                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut,
                isOrdered>=0 ? isOrdered+'0' : '?');
            sqlite3DebugPrintf("  was %s cost=%-3d,%3d order=%c\n",
                wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
                pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
          }
#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 = nOut;
        pTo->rCost = rCost;

        pTo->isOrdered = isOrdered;
        memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
        pTo->aLoop[iLoop] = pWLoop;
        if( nTo>=mxChoice ){
          mxI = 0;
          mxCost = aTo[0].rCost;
          mxOut = aTo[0].nRow;
................................................................................

#ifdef WHERETRACE_ENABLED  /* >=2 */
    if( sqlite3WhereTrace>=2 ){
      sqlite3DebugPrintf("---- after round %d ----\n", iLoop);
      for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
        sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
           wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
           pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?');
        if( pTo->isOrdered>0 ){
          sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
        }else{
          sqlite3DebugPrintf("\n");
        }
      }
    }
#endif
................................................................................
   && (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==pWInfo->pResultSet->nExpr ){
      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
    }

  }
  if( pWInfo->pOrderBy ){
    if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
      if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){
        pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
      }
    }else{

      pWInfo->nOBSat = pFrom->isOrdered;
      if( pWInfo->nOBSat<0 ) pWInfo->nOBSat = 0;
      pWInfo->revMask = pFrom->revLoop;
    }
  }
  pWInfo->nRowOut = pFrom->nRow;

  /* Free temporary memory and return success */
  sqlite3DbFree(db, pSpace);
................................................................................
  }
  if( pLoop->wsFlags ){
    pLoop->nOut = (LogEst)1;
    pWInfo->a[0].pWLoop = pLoop;
    pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur);
    pWInfo->a[0].iTabCur = iCur;
    pWInfo->nRowOut = 1;
    if( pWInfo->pOrderBy ) pWInfo->nOBSat =  pWInfo->pOrderBy->nExpr;
    if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
#ifdef SQLITE_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
................................................................................
** be used to compute the appropriate cursor depending on which index is
** used.
*/
WhereInfo *sqlite3WhereBegin(
  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 (or GROUP 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 */
................................................................................
  sqlite3 *db;               /* Database connection */
  int rc;                    /* Return code */


  /* Variable initialization */
  db = pParse->db;
  memset(&sWLB, 0, sizeof(sWLB));

  /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
  testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
  if( pOrderBy && pOrderBy->nExpr>=BMS ) pOrderBy = 0;
  sWLB.pOrderBy = pOrderBy;

  /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
  ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
  if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
    wctrlFlags &= ~WHERE_WANT_DISTINCT;
  }
................................................................................
      sWLB.pWC->a[ii].wtFlags |= TERM_CODED;
    }
  }

  /* Special case: No FROM clause
  */
  if( nTabList==0 ){
    if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
    if( wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
  }

  /* Assign a bit from the bitmask to every term in the FROM clause.
  **
................................................................................
  if( pParse->nErr || NEVER(db->mallocFailed) ){
    goto whereBeginError;
  }
#ifdef WHERETRACE_ENABLED /* !=0 */
  if( sqlite3WhereTrace ){
    int ii;
    sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
    if( pWInfo->nOBSat>0 ){
      sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask);
    }
    switch( pWInfo->eDistinct ){
      case WHERE_DISTINCT_UNIQUE: {
        sqlite3DebugPrintf("  DISTINCT=unique");
        break;
      }
      case WHERE_DISTINCT_ORDERED: {

Changes to src/whereInt.h.

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      u16 nEq;               /* Number of equality constraints */
      u16 nSkip;             /* Number of initial index columns to skip */
      Index *pIndex;         /* Index used, or NULL */
    } btree;
    struct {               /* Information for virtual tables */
      int idxNum;            /* Index number */
      u8 needFree;           /* True if sqlite3_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 ***********************/
................................................................................
** 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 */
  LogEst nRow;          /* Estimated number of rows generated by this path */
  LogEst 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,
................................................................................
  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 */
  LogEst nRowOut;           /* Estimated number of output rows */
  u16 wctrlFlags;           /* Flags originally passed to sqlite3WhereBegin() */
  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 */







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      u16 nEq;               /* Number of equality constraints */
      u16 nSkip;             /* Number of initial index columns to skip */
      Index *pIndex;         /* Index used, or NULL */
    } btree;
    struct {               /* Information for virtual tables */
      int idxNum;            /* Index number */
      u8 needFree;           /* True if sqlite3_free(idxStr) is needed */
      i8 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 ***********************/
................................................................................
** 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 */
  LogEst nRow;          /* Estimated number of rows generated by this path */
  LogEst rCost;         /* Total cost of this path */
  i8 isOrdered;         /* No. of ORDER BY terms satisfied. -1 for unknown */

  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,
................................................................................
  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 */
  LogEst nRowOut;           /* Estimated number of output rows */
  u16 wctrlFlags;           /* Flags originally passed to sqlite3WhereBegin() */
  i8 nOBSat;                /* Number of ORDER BY terms 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 */

Changes to test/distinct.test.

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  INSERT INTO t1 VALUES('a', 'b', 'c');
  INSERT INTO t1 VALUES('A', 'B', 'C');
}

foreach {tn sql temptables res} {
  1   "a, b FROM t1"                                       {}      {A B a b}
  2   "b, a FROM t1"                                       {}      {B A b a}
  3   "a, b, c FROM t1"                                    {hash}  {a b c A B C}
  4   "a, b, c FROM t1 ORDER BY a, b, c"                   {btree} {A B C a b c}
  5   "b FROM t1 WHERE a = 'a'"                            {}      {b}
  6   "b FROM t1 ORDER BY +b COLLATE binary"          {btree hash} {B b}
  7   "a FROM t1"                                          {}      {A a}
  8   "b COLLATE nocase FROM t1"                           {}      {b}
  9   "b COLLATE nocase FROM t1 ORDER BY b COLLATE nocase" {}      {b}
} {







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  INSERT INTO t1 VALUES('a', 'b', 'c');
  INSERT INTO t1 VALUES('A', 'B', 'C');
}

foreach {tn sql temptables res} {
  1   "a, b FROM t1"                                       {}      {A B a b}
  2   "b, a FROM t1"                                       {}      {B A b a}
  3   "a, b, c FROM t1"                                    {hash}  {A B C a b c}
  4   "a, b, c FROM t1 ORDER BY a, b, c"                   {btree} {A B C a b c}
  5   "b FROM t1 WHERE a = 'a'"                            {}      {b}
  6   "b FROM t1 ORDER BY +b COLLATE binary"          {btree hash} {B b}
  7   "a FROM t1"                                          {}      {A a}
  8   "b COLLATE nocase FROM t1"                           {}      {b}
  9   "b COLLATE nocase FROM t1 ORDER BY b COLLATE nocase" {}      {b}
} {

Changes to test/orderby5.test.

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  EXPLAIN QUERY PLAN
  SELECT DISTINCT c, b, a FROM t1 WHERE a=0;
} {~/B-TREE/}
do_execsql_test 1.7 {
  EXPLAIN QUERY PLAN
  SELECT DISTINCT c, b, a FROM t1 WHERE +a=0;
} {/B-TREE/}





do_execsql_test 2.1 {







  EXPLAIN QUERY PLAN




  SELECT * FROM t1 WHERE a=0 ORDER BY a, b, c;
} {~/B-TREE/}


do_execsql_test 2.2 {
  EXPLAIN QUERY PLAN
  SELECT * FROM t1 WHERE +a=0 ORDER BY a, b, c;
} {/B-TREE/}
do_execsql_test 2.3 {
  EXPLAIN QUERY PLAN
  SELECT * FROM t1 WHERE a=0 ORDER BY b, a, c;







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  EXPLAIN QUERY PLAN
  SELECT DISTINCT c, b, a FROM t1 WHERE a=0;
} {~/B-TREE/}
do_execsql_test 1.7 {
  EXPLAIN QUERY PLAN
  SELECT DISTINCT c, b, a FROM t1 WHERE +a=0;
} {/B-TREE/}

# In some cases, it is faster to do repeated index lookups than it is to
# sort.  But in other cases, it is faster to sort than to do repeated index
# lookups.
#
do_execsql_test 2.1a {
  CREATE TABLE t2(a,b,c);
  CREATE INDEX t2bc ON t2(b,c);
  ANALYZE;
  INSERT INTO sqlite_stat1 VALUES('t1','t1bc','1000000 10 9');
  INSERT INTO sqlite_stat1 VALUES('t2','t2bc','100 10 5');
  ANALYZE sqlite_master;

  EXPLAIN QUERY PLAN
  SELECT * FROM t2 WHERE a=0 ORDER BY a, b, c;
} {~/B-TREE/}
do_execsql_test 2.1b {
  EXPLAIN QUERY PLAN
  SELECT * FROM t1 WHERE a=0 ORDER BY a, b, c;
} {/B-TREE/}


do_execsql_test 2.2 {
  EXPLAIN QUERY PLAN
  SELECT * FROM t1 WHERE +a=0 ORDER BY a, b, c;
} {/B-TREE/}
do_execsql_test 2.3 {
  EXPLAIN QUERY PLAN
  SELECT * FROM t1 WHERE a=0 ORDER BY b, a, c;

Added test/orderby6.test.















































































































































































































































































































































































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# 2014-03-21
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing that the block-sort optimization.
#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix orderby6

# Run all tests twice.  Once with a normal table and a second time
# with a WITHOUT ROWID table
#
foreach {tn rowidclause} {1 {} 2 {WITHOUT ROWID}} {

  # Construct a table with 1000 rows and a split primary key
  #
  reset_db
  do_test $tn.1 {
    db eval "CREATE TABLE t1(a,b,c,PRIMARY KEY(b,c)) $rowidclause;"
    db eval {
      WITH RECURSIVE
       cnt(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM cnt WHERE x<1000)
     INSERT INTO t1 SELECT x, x%40, x/40 FROM cnt;
    }
  } {}

  # Run various ORDER BY queries that can benefit from block-sort.
  # Compare the output to the same output using a full-sort enforced
  # by adding + to each term of the ORDER BY clause.
  #
  do_execsql_test $tn.2 {
    SELECT b,a,c FROM t1 ORDER BY b,a,c;
  } [db eval {SELECT b,a,c FROM t1 ORDER BY +b,+a,+c}]
  do_execsql_test $tn.3 {
    SELECT b,a,c FROM t1 ORDER BY b,c DESC,a;
  } [db eval {SELECT b,a,c FROM t1 ORDER BY +b,+c DESC,+a}]
  do_execsql_test $tn.4 {
    SELECT b,a,c FROM t1 ORDER BY b DESC,c,a;
  } [db eval {SELECT b,a,c FROM t1 ORDER BY +b DESC,+c,+a}]
  do_execsql_test $tn.5 {
    SELECT b,a,c FROM t1 ORDER BY b DESC,a,c;
  } [db eval {SELECT b,a,c FROM t1 ORDER BY +b DESC,+a,+c}]

  # LIMIT and OFFSET clauses on block-sort queries.
  #
  do_execsql_test $tn.11 {
    SELECT a FROM t1 ORDER BY b, a LIMIT 10 OFFSET 20;
  } {840 880 920 960 1000 1 41 81 121 161}
  do_execsql_test $tn.11x {
    SELECT a FROM t1 ORDER BY +b, a LIMIT 10 OFFSET 20;
  } {840 880 920 960 1000 1 41 81 121 161}

  do_execsql_test $tn.12 {
    SELECT a FROM t1 ORDER BY b DESC, a LIMIT 10 OFFSET 20;
  } {839 879 919 959 999 38 78 118 158 198}
  do_execsql_test $tn.12 {
    SELECT a FROM t1 ORDER BY +b DESC, a LIMIT 10 OFFSET 20;
  } {839 879 919 959 999 38 78 118 158 198}

  do_execsql_test $tn.13 {
    SELECT a FROM t1 ORDER BY b, a DESC LIMIT 10 OFFSET 45;
  } {161 121 81 41 1 962 922 882 842 802}
  do_execsql_test $tn.13x {
    SELECT a FROM t1 ORDER BY +b, a DESC LIMIT 10 OFFSET 45;
  } {161 121 81 41 1 962 922 882 842 802}

  do_execsql_test $tn.14 {
    SELECT a FROM t1 ORDER BY b DESC, a LIMIT 10 OFFSET 45;
  } {838 878 918 958 998 37 77 117 157 197}
  do_execsql_test $tn.14x {
    SELECT a FROM t1 ORDER BY +b DESC, a LIMIT 10 OFFSET 45;
  } {838 878 918 958 998 37 77 117 157 197}

  # Many test cases where the LIMIT+OFFSET window is in various
  # alignments with block-sort boundaries.
  #
  foreach {tx limit offset orderby} {
     1  10 24 {+b,+a}
     2  10 25 {+b,+a}
     3  10 26 {+b,+a}
     4  10 39 {+b,+a}
     5  10 40 {+b,+a}
     6  10 41 {+b,+a}
     7  27 24 {+b,+a}
     8  27 49 {+b,+a}
     11 10 24 {+b DESC,+a}
     12 10 25 {+b DESC,+a}
     13 10 26 {+b DESC,+a}
     14 10 39 {+b DESC,+a}
     15 10 40 {+b DESC,+a}
     16 10 41 {+b DESC,+a}
     17 27 24 {+b DESC,+a}
     18 27 49 {+b DESC,+a}
     21 10 24 {+b,+a DESC}
     22 10 25 {+b,+a DESC}
     23 10 26 {+b,+a DESC}
     24 10 39 {+b,+a DESC}
     25 10 40 {+b,+a DESC}
     26 10 41 {+b,+a DESC}
     27 27 24 {+b,+a DESC}
     28 27 49 {+b,+a DESC}
     31 10 24 {+b DESC,+a DESC}
     32 10 25 {+b DESC,+a DESC}
     33 10 26 {+b DESC,+a DESC}
     34 10 39 {+b DESC,+a DESC}
     35 10 40 {+b DESC,+a DESC}
     36 10 41 {+b DESC,+a DESC}
     37 27 24 {+b DESC,+a DESC}
     38 27 49 {+b DESC,+a DESC}
  } {
    set sql1 "SELECT a FROM t1 ORDER BY $orderby LIMIT $limit OFFSET $offset;"
    set sql2 [string map {+ {}} $sql1]
    # puts $sql2\n$sql1\n[db eval $sql2]
    do_test $tn.21.$tx {db eval $::sql2} [db eval $sql1]
  }

  ########################################################################
  # A second test table, t2, has many columns open to sorting.
  do_test $tn.31 {
    db eval "CREATE TABLE t2(a,b,c,d,e,f,PRIMARY KEY(b,c,d,e,f)) $rowidclause;"
    db eval {
      WITH RECURSIVE
       cnt(x) AS (VALUES(0) UNION ALL SELECT x+1 FROM cnt WHERE x<242)
     INSERT INTO t2 SELECT x,  x%3, (x/3)%3, (x/9)%3, (x/27)%3, (x/81)%3
                      FROM cnt;
    }
  } {}

  do_execsql_test $tn.32 {
    SELECT a FROM t2 ORDER BY b,c,d,e,f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f;}]
  do_execsql_test $tn.33 {
    SELECT a FROM t2 ORDER BY b,c,d,e,+f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f;}]
  do_execsql_test $tn.34 {
    SELECT a FROM t2 ORDER BY b,c,d,+e,+f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f;}]
  do_execsql_test $tn.35 {
    SELECT a FROM t2 ORDER BY b,c,+d,+e,+f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f;}]
  do_execsql_test $tn.36 {
    SELECT a FROM t2 ORDER BY b,+c,+d,+e,+f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f;}]

  do_execsql_test $tn.37 {
    SELECT a FROM t2 ORDER BY b,c,d,e,f DESC;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f DESC;}]
  do_execsql_test $tn.38 {
    SELECT a FROM t2 ORDER BY b,c,d,e DESC,f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e DESC,+f;}]
  do_execsql_test $tn.39 {
    SELECT a FROM t2 ORDER BY b,c,d DESC,e,f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d DESC,+e,+f;}]
  do_execsql_test $tn.40 {
    SELECT a FROM t2 ORDER BY b,c DESC,d,e,f;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c DESC,+d,+e,+f;}]
  do_execsql_test $tn.41 {
    SELECT a FROM t2 ORDER BY b DESC,c,d,e,f;
  } [db eval {SELECT a FROM t2 ORDER BY +b DESC,+c,+d,+e,+f;}]

  do_execsql_test $tn.42 {
    SELECT a FROM t2 ORDER BY b DESC,c DESC,d,e,f LIMIT 31;
  } [db eval {SELECT a FROM t2 ORDER BY +b DESC,+c DESC,+d,+e,+f LIMIT 31}]
  do_execsql_test $tn.43 {
    SELECT a FROM t2 ORDER BY b,c,d,e,f DESC LIMIT 8 OFFSET 7;
  } [db eval {SELECT a FROM t2 ORDER BY +b,+c,+d,+e,+f DESC LIMIT 8 OFFSET 7}]


}



finish_test

Changes to test/whereG.test.

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do_eqp_test whereG-1.5 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND composer.cid=track.cid
     AND album.aid=track.aid;
} {/.*track.*composer.*album.*/}
do_execsql_test whereG-1.6 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND composer.cid=track.cid
     AND album.aid=track.aid;
} {{Mass in B Minor, BWV 232}}
................................................................................

do_eqp_test whereG-1.7 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND unlikely(composer.cid=track.cid)
     AND unlikely(album.aid=track.aid);
} {/.*track.*composer.*album.*/}
do_execsql_test whereG-1.8 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND unlikely(composer.cid=track.cid)
     AND unlikely(album.aid=track.aid);
} {{Mass in B Minor, BWV 232}}







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do_eqp_test whereG-1.5 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND composer.cid=track.cid
     AND album.aid=track.aid;
} {/.*track.*(composer.*album|album.*composer).*/}
do_execsql_test whereG-1.6 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND composer.cid=track.cid
     AND album.aid=track.aid;
} {{Mass in B Minor, BWV 232}}
................................................................................

do_eqp_test whereG-1.7 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND unlikely(composer.cid=track.cid)
     AND unlikely(album.aid=track.aid);
} {/.*track.*(composer.*album|album.*composer).*/}
do_execsql_test whereG-1.8 {
  SELECT DISTINCT aname
    FROM album, composer, track
   WHERE cname LIKE '%bach%'
     AND unlikely(composer.cid=track.cid)
     AND unlikely(album.aid=track.aid);
} {{Mass in B Minor, BWV 232}}