SQLite

  char *p2 = a2;
  char *p;
  char *aOut;
  int bFirstOut = 0;

  *paOut = 0;
  *pnOut = 0;

  /* Allocate space for the output. Both the input and output doclists
  ** are delta encoded. If they are in ascending order (bDescDoclist==0),
  ** then the first docid in each list is simply encoded as a varint. For
  ** each subsequent docid, the varint stored is the difference between the
  ** current and previous docid (a positive number - since the list is in
  ** ascending order).
  **
  ** The first docid written to the output is therefore encoded using the 
  ** same number of bytes as it is in whichever of the input lists it is
  ** read from. And each subsequent docid read from the same input list 
  ** consumes either the same or less bytes as it did in the input (since
  ** the difference between it and the previous value in the output must
  ** be a positive value less than or equal to the delta value read from 
  ** the input list). The same argument applies to all but the first docid
  ** read from the 'other' list. And to the contents of all position lists
  ** that will be copied and merged from the input to the output.
  **
  ** However, if the first docid copied to the output is a negative number,
  ** then the encoding of the first docid from the 'other' input list may
  ** be larger in the output than it was in the input (since the delta value
  ** may be a larger positive integer than the actual docid).
  **
  ** The space required to store the output is therefore the sum of the
  ** sizes of the two inputs, plus enough space for exactly one of the input
  ** docids to grow. 
  **
  ** A symetric argument may be made if the doclists are in descending 
  ** order.
  */
  aOut = sqlite3_malloc(n1+n2+FTS3_VARINT_MAX-1);
  if( !aOut ) return SQLITE_NOMEM;

  p = aOut;
  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
  while( p1 || p2 ){
    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);

      fts3PoslistCopy(&p, &p2);
      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
    }
  }

  *paOut = aOut;
  *pnOut = (p-aOut);
  assert( *pnOut<=n1+n2+FTS3_VARINT_MAX-1 );
  return SQLITE_OK;
}

/*
** This function does a "phrase" merge of two doclists. In a phrase merge,
** the output contains a copy of each position from the right-hand input
** doclist for which there is a position in the left-hand input doclist

  if( pKey ){
    assert( nKey==(i64)(int)nKey );
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(
        pCur->pKeyInfo, aSpace, sizeof(aSpace), &pFree
    );
    if( pIdxKey==0 ) return SQLITE_NOMEM;
    sqlite3VdbeRecordUnpack(pCur->pKeyInfo, (int)nKey, pKey, pIdxKey);
  }else{
    pIdxKey = 0;
  }
  rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);
  if( pFree ){
    sqlite3DbFree(pCur->pKeyInfo->db, pFree);
  }

    struct SrcList_item *pOldItem = &p->a[i];
    Table *pTab;
    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
    pNewItem->jointype = pOldItem->jointype;
    pNewItem->iCursor = pOldItem->iCursor;
    pNewItem->addrFillSub = pOldItem->addrFillSub;
    pNewItem->regReturn = pOldItem->regReturn;
    pNewItem->isCorrelated = pOldItem->isCorrelated;
    pNewItem->zIndex = sqlite3DbStrDup(db, pOldItem->zIndex);
    pNewItem->notIndexed = pOldItem->notIndexed;
    pNewItem->pIndex = pOldItem->pIndex;
    pTab = pNewItem->pTab = pOldItem->pTab;
    if( pTab ){
      pTab->nRef++;

    ** successful here.
    */
    assert(v);
    if( iCol<0 ){
      int iMem = ++pParse->nMem;
      int iAddr;

      iAddr = sqlite3VdbeAddOp1(v, OP_Once, iMem);


      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
      eType = IN_INDEX_ROWID;

      sqlite3VdbeJumpHere(v, iAddr);
    }else{
      Index *pIdx;                         /* Iterator variable */

         && (!mustBeUnique || (pIdx->nColumn==1 && pIdx->onError!=OE_None))
        ){
          int iMem = ++pParse->nMem;
          int iAddr;
          char *pKey;
  
          pKey = (char *)sqlite3IndexKeyinfo(pParse, pIdx);
          iAddr = sqlite3VdbeAddOp1(v, OP_Once, iMem);

  
          sqlite3VdbeAddOp4(v, OP_OpenRead, iTab, pIdx->tnum, iDb,
                               pKey,P4_KEYINFO_HANDOFF);
          VdbeComment((v, "%s", pIdx->zName));
          eType = IN_INDEX_INDEX;

          sqlite3VdbeJumpHere(v, iAddr);

  int rMayHaveNull,       /* Register that records whether NULLs exist in RHS */
  int isRowid             /* If true, LHS of IN operator is a rowid */
){
  int testAddr = 0;                       /* One-time test address */
  int rReg = 0;                           /* Register storing resulting */
  Vdbe *v = sqlite3GetVdbe(pParse);
  if( NEVER(v==0) ) return 0;
  assert( sqlite3VdbeCurrentAddr(v)>0 );
  sqlite3ExprCachePush(pParse);

  /* This code must be run in its entirety every time it is encountered
  ** if any of the following is true:
  **
  **    *  The right-hand side is a correlated subquery
  **    *  The right-hand side is an expression list containing variables
  **    *  We are inside a trigger
  **
  ** If all of the above are false, then we can run this code just once
  ** save the results, and reuse the same result on subsequent invocations.
  */
  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->pTriggerTab ){
    int mem = ++pParse->nMem;

    testAddr = sqlite3VdbeAddOp1(v, OP_Once, mem);
    assert( testAddr>0 || pParse->db->mallocFailed );
  }

#ifndef SQLITE_OMIT_EXPLAIN
  if( pParse->explain==2 ){
    char *zMsg = sqlite3MPrintf(
        pParse->db, "EXECUTE %s%s SUBQUERY %d", testAddr?"":"CORRELATED ",

          /* If the expression is not constant then we will need to
          ** disable the test that was generated above that makes sure
          ** this code only executes once.  Because for a non-constant
          ** expression we need to rerun this code each time.
          */
          if( testAddr && !sqlite3ExprIsConstant(pE2) ){
            sqlite3VdbeChangeToNoop(v, testAddr);
            testAddr = 0;
          }

          /* Evaluate the expression and insert it into the temp table */
          if( isRowid && sqlite3ExprIsInteger(pE2, &iValToIns) ){
            sqlite3VdbeAddOp3(v, OP_InsertInt, pExpr->iTable, r2, iValToIns);
          }else{

      rReg = dest.iParm;
      ExprSetIrreducible(pExpr);
      break;
    }
  }

  if( testAddr ){
    sqlite3VdbeJumpHere(v, testAddr);
  }
  sqlite3ExprCachePop(pParse, 1);

  return rReg;
}
#endif /* SQLITE_OMIT_SUBQUERY */

  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 );
  }
  return pNew;
}

/*
** Delete the given Select structure and all of its substructures.
*/

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
  for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
    struct SrcList_item *pItem = &pTabList->a[i];
    SelectDest dest;
    Select *pSub = pItem->pSelect;
    int isAggSub;

    if( pSub==0 ) continue;
    if( pItem->addrFillSub ){
      sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub);
      continue;
    }

    /* Increment Parse.nHeight by the height of the largest expression
    ** tree refered to by this, the parent select. The child select
    ** may contain expression trees of at most
    ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
    ** more conservative than necessary, but much easier than enforcing
    ** an exact limit.
    */
    pParse->nHeight += sqlite3SelectExprHeight(p);


    isAggSub = (pSub->selFlags & SF_Aggregate)!=0;
    if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
      /* This subquery can be absorbed into its parent. */
      if( isAggSub ){
        isAgg = 1;
        p->selFlags |= SF_Aggregate;
      }
      i = -1;
    }else{
      /* Generate a subroutine that will fill an ephemeral table with
      ** the content of this subquery.  pItem->addrFillSub will point
      ** to the address of the generated subroutine.  pItem->regReturn
      ** is a register allocated to hold the subroutine return address
      */
      int topAddr;
      int onceAddr = 0;
      int retAddr;
      assert( pItem->addrFillSub==0 );
      pItem->regReturn = ++pParse->nMem;
      topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
      pItem->addrFillSub = topAddr+1;
      VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
      if( pItem->isCorrelated==0 && pParse->pTriggerTab==0 ){
        /* If the subquery is no correlated and if we are not inside of
        ** a trigger, then we only need to compute the value of the subquery
        ** once. */
        int regOnce = ++pParse->nMem;
        onceAddr = sqlite3VdbeAddOp1(v, OP_Once, regOnce);
      }
      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);

      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);

      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
      retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
      VdbeComment((v, "end %s", pItem->pTab->zName));
      sqlite3VdbeChangeP1(v, topAddr, retAddr);

    }
    if( /*pParse->nErr ||*/ db->mallocFailed ){
      goto select_end;
    }
    pParse->nHeight -= sqlite3SelectExprHeight(p);
    pTabList = p->pSrc;
    if( !IgnorableOrderby(pDest) ){

    if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut;

    /* If sorting index that was created by a prior OP_OpenEphemeral 
    ** instruction ended up not being needed, then change the OP_OpenEphemeral
    ** into an OP_Noop.
    */
    if( addrSortIndex>=0 && pOrderBy==0 ){
      sqlite3VdbeChangeToNoop(v, addrSortIndex);
      p->addrOpenEphm[2] = -1;
    }

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

      /* End of the loop
      */
      if( groupBySort ){
        sqlite3VdbeAddOp2(v, OP_SorterNext, sAggInfo.sortingIdx, addrTopOfLoop);
      }else{
        sqlite3WhereEnd(pWInfo);
        sqlite3VdbeChangeToNoop(v, addrSortingIdx);
      }

      /* Output the final row of result
      */
      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
      VdbeComment((v, "output final row"));

  i16 nAlloc;      /* Number of entries allocated in a[] below */
  struct SrcList_item {
    char *zDatabase;  /* Name of database holding this table */
    char *zName;      /* Name of the table */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    int addrFillSub;  /* Address of subroutine to manifest a subquery */
    int regReturn;    /* Register holding return address of addrFillSub */
    u8 jointype;      /* Type of join between this able and the previous */
    u8 notIndexed;    /* True if there is a NOT INDEXED clause */
    u8 isCorrelated;  /* True if sub-query is correlated */
#ifndef SQLITE_OMIT_EXPLAIN
    u8 iSelectId;     /* If pSelect!=0, the id of the sub-select in EQP */
#endif
    int iCursor;      /* The VDBE cursor number used to access this table */

    sqlite3VdbeMemSetNull(pOut);
  }else{
    sqlite3VdbeMemSetInt64(pOut, ~sqlite3VdbeIntValue(pIn1));
  }
  break;
}

/* Opcode: Once P1 P2 * * *
**
** Jump to P2 if the value in register P1 is a not null or zero.  If
** the value is NULL or zero, fall through and change the P1 register
** to an integer 1.
**
** When P1 is not used otherwise in a program, this opcode falls through
** once and jumps on all subsequent invocations.  It is the equivalent
** of "OP_If P1 P2", followed by "OP_Integer 1 P1".
*/
/* Opcode: If P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is true.  The value
** is considered true if it is numeric and non-zero.  If the value
** in P1 is NULL then take the jump if P3 is true.
*/
/* Opcode: IfNot P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is False.  The value
** is considered true if it has a numeric value of zero.  If the value
** in P1 is NULL then take the jump if P3 is true.
*/
case OP_Once:               /* jump, in1 */
case OP_If:                 /* jump, in1 */
case OP_IfNot: {            /* jump, in1 */
  int c;
  pIn1 = &aMem[pOp->p1];
  if( pIn1->flags & MEM_Null ){
    c = pOp->p3;
  }else{
#ifdef SQLITE_OMIT_FLOATING_POINT
    c = sqlite3VdbeIntValue(pIn1)!=0;
#else
    c = sqlite3VdbeRealValue(pIn1)!=0.0;
#endif
    if( pOp->opcode==OP_IfNot ) c = !c;
  }
  if( c ){
    pc = pOp->p2-1;
  }else if( pOp->opcode==OP_Once ){
    assert( (pIn1->flags & (MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame))==0 );
    memAboutToChange(p, pIn1);
    pIn1->flags = MEM_Int;
    pIn1->u.i = 1;
    REGISTER_TRACE(pOp->p1, pIn1);
  }
  break;
}

/* Opcode: IsNull P1 P2 * * *
**
** Jump to P2 if the value in register P1 is NULL.

int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
void sqlite3VdbeAddParseSchemaOp(Vdbe*,int,char*);
void sqlite3VdbeChangeP1(Vdbe*, u32 addr, int P1);
void sqlite3VdbeChangeP2(Vdbe*, u32 addr, int P2);
void sqlite3VdbeChangeP3(Vdbe*, u32 addr, int P3);
void sqlite3VdbeChangeP5(Vdbe*, u8 P5);
void sqlite3VdbeJumpHere(Vdbe*, int addr);
void sqlite3VdbeChangeToNoop(Vdbe*, int addr);
void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeDeleteObject(sqlite3*,Vdbe*);

*/
void sqlite3VdbeLinkSubProgram(Vdbe *pVdbe, SubProgram *p){
  p->pNext = pVdbe->pProgram;
  pVdbe->pProgram = p;
}

/*
** Change the opcode at addr into OP_Noop
*/
void sqlite3VdbeChangeToNoop(Vdbe *p, int addr){
  if( p->aOp ){
    VdbeOp *pOp = &p->aOp[addr];
    sqlite3 *db = p->db;

    freeP4(db, pOp->p4type, pOp->p4.p);
    memset(pOp, 0, sizeof(pOp[0]));
    pOp->opcode = OP_Noop;


  }
}

/*
** Change the value of the P4 operand for a specific instruction.
** This routine is useful when a large program is loaded from a
** static array using sqlite3VdbeAddOpList but we want to make a

** having to double-check to make sure that the result is non-negative. But
** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
** check the value of p->nOp-1 before continuing.
*/
VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
  /* C89 specifies that the constant "dummy" will be initialized to all
  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
  static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
  assert( p->magic==VDBE_MAGIC_INIT );
  if( addr<0 ){
#ifdef SQLITE_OMIT_TRACE
    if( p->nOp==0 ) return (VdbeOp*)&dummy;
#endif
    addr = p->nOp - 1;
  }

      sqlite3VdbeChangeP3(v, 1, pTab->pSchema->iGeneration);

      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb); 

      /* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
      sqlite3VdbeChangeToNoop(v, 2);
#else
      sqlite3VdbeChangeP1(v, 2, iDb);
      sqlite3VdbeChangeP2(v, 2, pTab->tnum);
      sqlite3VdbeChangeP3(v, 2, flags);
      sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
#endif

      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
      ** parameter of the other to pTab->tnum.  */
      sqlite3VdbeChangeToNoop(v, 4 - flags);
      sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
      sqlite3VdbeChangeP3(v, 3 + flags, iDb);

      /* Configure the number of columns. Configure the cursor to
      ** think that the table has one more column than it really
      ** does. An OP_Column to retrieve this imaginary column will
      ** always return an SQL NULL. This is useful because it means

  VdbeSorterIter *pIter           /* Iterator to advance */
){
  int rc;                         /* Return Code */
  int nRead;                      /* Number of bytes read */
  int nRec = 0;                   /* Size of record in bytes */
  int iOff = 0;                   /* Size of serialized size varint in bytes */

  assert( pIter->iEof>=pIter->iReadOff );
  if( pIter->iEof-pIter->iReadOff>5 ){
    nRead = 5;
  }else{
    nRead = (int)(pIter->iEof - pIter->iReadOff);
  }
  if( nRead<=0 ){
    /* This is an EOF condition */
    vdbeSorterIterZero(db, pIter);
    return SQLITE_OK;
  }

  rc = sqlite3OsRead(pIter->pFile, pIter->aAlloc, nRead, pIter->iReadOff);

** field. For the purposes of the comparison, ignore it. Also, if bOmitRowid
** is true and key1 contains even a single NULL value, it is considered to
** be less than key2. Even if key2 also contains NULL values.
**
** If pKey2 is passed a NULL pointer, then it is assumed that the pCsr->aSpace
** has been allocated and contains an unpacked record that is used as key2.
*/
static void vdbeSorterCompare(
  VdbeCursor *pCsr,               /* Cursor object (for pKeyInfo) */
  int bOmitRowid,                 /* Ignore rowid field at end of keys */
  void *pKey1, int nKey1,         /* Left side of comparison */
  void *pKey2, int nKey2,         /* Right side of comparison */
  int *pRes                       /* OUT: Result of comparison */
){
  KeyInfo *pKeyInfo = pCsr->pKeyInfo;

  if( bOmitRowid ){
    r2->nField = pKeyInfo->nField;
    assert( r2->nField>0 );
    for(i=0; i<r2->nField; i++){
      if( r2->aMem[i].flags & MEM_Null ){
        *pRes = -1;
        return;
      }
    }
    r2->flags |= UNPACKED_PREFIX_MATCH;
  }

  *pRes = sqlite3VdbeRecordCompare(nKey1, pKey1, r2);

}

/*
** This function is called to compare two iterator keys when merging 
** multiple b-tree segments. Parameter iOut is the index of the aTree[] 
** value to recalculate.
*/

  if( p1->pFile==0 ){
    iRes = i2;
  }else if( p2->pFile==0 ){
    iRes = i1;
  }else{
    int res;

    assert( pCsr->pSorter->pUnpacked!=0 );  /* allocated in vdbeSorterMerge() */
    vdbeSorterCompare(
        pCsr, 0, p1->aKey, p1->nKey, p2->aKey, p2->nKey, &res
    );




    if( res<=0 ){
      iRes = i1;
    }else{
      iRes = i2;
    }
  }

      SQLITE_OPEN_TEMP_JOURNAL |
      SQLITE_OPEN_READWRITE    | SQLITE_OPEN_CREATE |
      SQLITE_OPEN_EXCLUSIVE    | SQLITE_OPEN_DELETEONCLOSE, &dummy
  );
}

/*
** Merge the two sorted lists p1 and p2 into a single list.
** Set *ppOut to the head of the new list.
*/
static void vdbeSorterMerge(

  VdbeCursor *pCsr,               /* For pKeyInfo */
  SorterRecord *p1,               /* First list to merge */
  SorterRecord *p2,               /* Second list to merge */
  SorterRecord **ppOut            /* OUT: Head of merged list */
){

  SorterRecord *pFinal = 0;
  SorterRecord **pp = &pFinal;
  void *pVal2 = p2 ? p2->pVal : 0;

  while( p1 && p2 ){
    int res;
    vdbeSorterCompare(pCsr, 0, p1->pVal, p1->nVal, pVal2, p2->nVal, &res);








    if( res<=0 ){
      *pp = p1;
      pp = &p1->pNext;
      p1 = p1->pNext;
      pVal2 = 0;
    }else{
      *pp = p2;
       pp = &p2->pNext;
      p2 = p2->pNext;
      if( p2==0 ) break;
      pVal2 = p2->pVal;
    }
  }
  *pp = p1 ? p1 : p2;

  *ppOut = pFinal;

}

/*
** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK
** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error
** occurs.
*/
static int vdbeSorterSort(VdbeCursor *pCsr){

  int i;
  SorterRecord **aSlot;
  SorterRecord *p;
  VdbeSorter *pSorter = pCsr->pSorter;

  aSlot = (SorterRecord **)sqlite3MallocZero(64 * sizeof(SorterRecord *));
  if( !aSlot ){
    return SQLITE_NOMEM;
  }

  p = pSorter->pRecord;
  while( p ){
    SorterRecord *pNext = p->pNext;
    p->pNext = 0;
    for(i=0; aSlot[i]; i++){
      vdbeSorterMerge(pCsr, p, aSlot[i], &p);
      aSlot[i] = 0;
    }




    aSlot[i] = p;
    p = pNext;
  }

  p = 0;
  for(i=0; i<64; i++){

    vdbeSorterMerge(pCsr, p, aSlot[i], &p);



  }
  pSorter->pRecord = p;

  sqlite3_free(aSlot);
  return SQLITE_OK;
}


/*
** Write the current contents of the in-memory linked-list to a PMA. Return
** SQLITE_OK if successful, or an SQLite error code otherwise.
**

  VdbeSorter *pSorter = pCsr->pSorter;

  if( pSorter->nInMemory==0 ){
    assert( pSorter->pRecord==0 );
    return rc;
  }

  rc = vdbeSorterSort(pCsr);

  /* If the first temporary PMA file has not been opened, open it now. */
  if( rc==SQLITE_OK && pSorter->pTemp1==0 ){
    rc = vdbeSorterOpenTempFile(db, &pSorter->pTemp1);
    assert( rc!=SQLITE_OK || pSorter->pTemp1 );
    assert( pSorter->iWriteOff==0 );
    assert( pSorter->nPMA==0 );

  /* If no data has been written to disk, then do not do so now. Instead,
  ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly
  ** from the in-memory list.  */
  if( pSorter->nPMA==0 ){
    *pbEof = !pSorter->pRecord;
    assert( pSorter->aTree==0 );
    return vdbeSorterSort(pCsr);
  }

  /* Write the current b-tree to a PMA. Close the b-tree cursor. */
  rc = vdbeSorterListToPMA(db, pCsr);
  if( rc!=SQLITE_OK ) return rc;

  /* Allocate space for aIter[] and aTree[]. */

** key.
*/
int sqlite3VdbeSorterCompare(
  VdbeCursor *pCsr,               /* Sorter cursor */
  Mem *pVal,                      /* Value to compare to current sorter key */
  int *pRes                       /* OUT: Result of comparison */
){

  VdbeSorter *pSorter = pCsr->pSorter;
  void *pKey; int nKey;           /* Sorter key to compare pVal with */

  pKey = vdbeSorterRowkey(pSorter, &nKey);
  vdbeSorterCompare(pCsr, 1, pVal->z, pVal->n, pKey, nKey, pRes);

  return SQLITE_OK;
}

#endif /* #ifndef SQLITE_OMIT_MERGE_SORT */

    }
  }
  return mask;
}
static Bitmask exprSelectTableUsage(WhereMaskSet *pMaskSet, Select *pS){
  Bitmask mask = 0;
  while( pS ){
    SrcList *pSrc = pS->pSrc;
    mask |= exprListTableUsage(pMaskSet, pS->pEList);
    mask |= exprListTableUsage(pMaskSet, pS->pGroupBy);
    mask |= exprListTableUsage(pMaskSet, pS->pOrderBy);
    mask |= exprTableUsage(pMaskSet, pS->pWhere);
    mask |= exprTableUsage(pMaskSet, pS->pHaving);
    if( ALWAYS(pSrc!=0) ){
      int i;
      for(i=0; i<pSrc->nSrc; i++){
        mask |= exprSelectTableUsage(pMaskSet, pSrc->a[i].pSelect);
        mask |= exprTableUsage(pMaskSet, pSrc->a[i].pOn);
      }
    }
    pS = pS->pPrior;
  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is

  Bitmask extraCols;          /* Bitmap of additional columns */

  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  regIsInit = ++pParse->nMem;
  addrInit = sqlite3VdbeAddOp1(v, OP_Once, regIsInit);


  /* Count the number of columns that will be added to the index
  ** and used to match WHERE clause constraints */
  nColumn = 0;
  pTable = pSrc->pTab;
  pWCEnd = &pWC->a[pWC->nTerm];
  idxCols = 0;

    INSERT INTO t2 VALUES('cc aa');
    SELECT docid FROM t2 WHERE t2 MATCH 'aa';
  END;
} {3 1}
do_execsql_test 2.3 {
  SELECT docid FROM t2 WHERE t2 MATCH 'aa';
} {3 1}

#-------------------------------------------------------------------------
# Test that ticket [56be976859] has been fixed.
#
do_execsql_test 3.1 {
  CREATE VIRTUAL TABLE t3 USING fts4(x, order=DESC);
  INSERT INTO t3(docid, x) VALUES(113382409004785664, 'aa');
  INSERT INTO t3(docid, x) VALUES(1, 'ab');
  SELECT rowid FROM t3 WHERE x MATCH 'a*' ORDER BY docid DESC;
} {113382409004785664 1}
do_execsql_test 3.2 {
  CREATE VIRTUAL TABLE t4 USING fts4(x);
  INSERT INTO t4(docid, x) VALUES(-113382409004785664, 'aa');
  INSERT INTO t4(docid, x) VALUES(1, 'ab');
  SELECT rowid FROM t4 WHERE x MATCH 'a*';
} {-113382409004785664 1}



finish_test

# 2011 September 16
#
# 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 script is testing correlated subqueries
#
#

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

ifcapable !subquery {
  finish_test
  return
}

do_test subquery2-1.1 {
  execsql {
    BEGIN;
    CREATE TABLE t1(a,b);
    INSERT INTO t1 VALUES(1,2);
    INSERT INTO t1 VALUES(3,4);
    INSERT INTO t1 VALUES(5,6);
    INSERT INTO t1 VALUES(7,8);
    CREATE TABLE t2(c,d);
    INSERT INTO t2 VALUES(1,1);
    INSERT INTO t2 VALUES(3,9);
    INSERT INTO t2 VALUES(5,25);
    INSERT INTO t2 VALUES(7,49);
    CREATE TABLE t3(e,f);
    INSERT INTO t3 VALUES(1,1);
    INSERT INTO t3 VALUES(3,27);
    INSERT INTO t3 VALUES(5,125);
    INSERT INTO t3 VALUES(7,343);
    COMMIT;
  }
  execsql {
    SELECT a FROM t1
     WHERE b IN (SELECT x+1 FROM (SELECT DISTINCT f/(a*a) AS x FROM t3));
  }
} {1 3 5 7}
do_test subquery2-1.2 {
  execsql {
    CREATE INDEX t1b ON t1(b);
    SELECT a FROM t1
     WHERE b IN (SELECT x+1 FROM (SELECT DISTINCT f/(a*a) AS x FROM t3));
  }
} {1 3 5 7}

do_test subquery2-1.11 {
  execsql {
    SELECT a FROM t1
     WHERE +b=(SELECT x+1 FROM (SELECT DISTINCT f/(a*a) AS x FROM t3));
  }
} {1}
do_test subquery2-1.12 {
  execsql {
    SELECT a FROM t1
     WHERE b=(SELECT x+1 FROM (SELECT DISTINCT f/(a*a) AS x FROM t3));
  }
} {1}

do_test subquery2-1.21 {
  execsql {
    SELECT a FROM t1
     WHERE +b=(SELECT x+1 FROM 
                 (SELECT DISTINCT f/d AS x FROM t2 JOIN t3 ON d*a=f))
  }
} {1 3 5 7}
do_test subquery2-1.22 {
  execsql {
    SELECT a FROM t1
     WHERE b=(SELECT x+1 FROM 
                 (SELECT DISTINCT f/d AS x FROM t2 JOIN t3 ON d*a=f))
  }
} {1 3 5 7}


finish_test

   CREATE INDEX t4x ON t4(x);
    SELECT * FROM t3, t4, t5
     WHERE (v=111 AND x=w AND z!=999) OR (v=333 AND x=444)
     ORDER BY v, w, x, y, z;
  }
} {111 222 222 333 888 333 444 444 555 888 333 444 444 555 999}


# Ticket [2c2de252666662f5459904fc33a9f2956cbff23c]
#
do_test tkt-31338-3.1 {
  foreach x [db eval {SELECT name FROM sqlite_master WHERE type='table'}] {
     db eval "DROP TABLE $x"
  }
  db eval {
    CREATE TABLE t1(a,b,c,d);
    CREATE TABLE t2(e,f);
    INSERT INTO t1 VALUES(1,2,3,4);
    INSERT INTO t2 VALUES(10,-8);
    CREATE INDEX t1a ON t1(a);
    CREATE INDEX t1b ON t1(b);
    CREATE TABLE t3(g);
    INSERT INTO t3 VALUES(4);
    CREATE TABLE t4(h);
    INSERT INTO t4 VALUES(5);
    
    SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
     WHERE (a=1 AND h=4)
         OR (b IN (
               SELECT x FROM (SELECT e+f AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
  }    
} {4 1 2 3 4 {}}
do_test tkt-31338-3.2 {
  db eval {    
    SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
     WHERE (a=1 AND h=4)
         OR (b=2 AND b NOT IN (
               SELECT x+1 FROM (SELECT e+f AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
  }    
} {4 1 2 3 4 {}}
do_test tkt-31338-3.3 {
  db eval {    
    SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
     WHERE (+a=1 AND h=4)
         OR (b IN (
               SELECT x FROM (SELECT e+f AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
  }    
} {4 1 2 3 4 {}}
do_test tkt-31338-3.4 {
  db eval {    
    SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
     WHERE (a=1 AND h=4)
         OR (+b IN (
               SELECT x FROM (SELECT e+f AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
  }    
} {4 1 2 3 4 {}}

do_test tkt-31338-3.5 {
  db eval {
    CREATE TABLE t5(a,b,c,d,e,f);
    CREATE TABLE t6(g,h);
    CREATE TRIGGER t6r AFTER INSERT ON t6 BEGIN
      INSERT INTO t5    
        SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
         WHERE (a=1 AND h=4)
            OR (b IN (
               SELECT x FROM (SELECT e+f AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
    END;
    INSERT INTO t6 VALUES(88,99);
    SELECT * FROM t5;
  }    
} {4 1 2 3 4 {}}

do_test tkt-31338-3.6 {
  db eval {    
    INSERT INTO t1 VALUES(2,4,3,4);
    INSERT INTO t1 VALUES(99,101,3,4);
    INSERT INTO t1 VALUES(98,97,3,4);
    SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
     WHERE (a=1 AND h=4)
         OR (b IN (
               SELECT x+a FROM (SELECT e+f AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
  }    
} {4 2 4 3 4 {} 4 99 101 3 4 {}}

do_test tkt-31338-3.7 {
  db eval {
    SELECT * FROM t3 LEFT JOIN t1 ON d=g LEFT JOIN t4 ON c=h
     WHERE (a=1 AND h=4)
         OR (b IN (
               SELECT x FROM (SELECT e+f+a AS x, e FROM t2 ORDER BY 1 LIMIT 2)
               GROUP BY e
            ));
  }    
} {4 2 4 3 4 {} 4 99 101 3 4 {}}


finish_test

# Run this TCL script using "testfixture" in order get a report that shows
# how much disk space is used by a particular data to actually store data
# versus how much space is unused.
#

if {[catch {
if {![info exists argv0]} {
  set argv0 [file rootname [file tail [info nameofexecutable]]]
}

# Get the name of the database to analyze
#
#set argv $argv0
if {![info exists argv] || [llength $argv]!=1} {
  puts stderr "Usage: $argv0 database-name"
  exit 1
}
set file_to_analyze [lindex $argv 0]
if {![file exists $file_to_analyze]} {
  puts stderr "No such file: $file_to_analyze"
  exit 1
}
if {![file readable $file_to_analyze]} {
  puts stderr "File is not readable: $file_to_analyze"
  exit 1
}
if {[file size $file_to_analyze]<512} {
  puts stderr "Empty or malformed database: $file_to_analyze"
  exit 1
}

# Open the database
#
sqlite3 db $file_to_analyze
register_dbstat_vtab db

set pageSize [db one {PRAGMA page_size}]

#set DB [btree_open $file_to_analyze 1000 0]

# In-memory database for collecting statistics. This script loops through
# the tables and indices in the database being analyzed, adding a row for each
# to an in-memory database (for which the schema is shown below). It then
# queries the in-memory db to produce the space-analysis report.
#
sqlite3 mem :memory: