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Overview
Comment:Simplify the where.c logic by flipping expression over so that the controlling variable is always on the left. (CVS 1838)
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Timelines: family | ancestors | descendants | both | trunk
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SHA1: ec8bfa3891dbf0f3172e31cf322974c03f9af59a
User & Date: drh 2004-07-20 18:23:15.000
Context
2004-07-21
02:53
Minor coding enhancements. (CVS 1839) (check-in: 65c3af74c1 user: drh tags: trunk)
2004-07-20
18:23
Simplify the where.c logic by flipping expression over so that the controlling variable is always on the left. (CVS 1838) (check-in: ec8bfa3891 user: drh tags: trunk)
14:06
Lemon collapses common destructors and reduce actions into a single case. (CVS 1837) (check-in: 3c5aa850ee user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/where.c.
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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.
**
** $Id: where.c,v 1.110 2004/07/19 19:14:01 drh Exp $
*/
#include "sqliteInt.h"

/*
** 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 an AND operator.







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**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.
**
** $Id: where.c,v 1.111 2004/07/20 18:23:15 drh Exp $
*/
#include "sqliteInt.h"

/*
** 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 an AND operator.
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    case TK_EQ:
    case TK_IN:
      return 1;
    default:
      return 0;
  }
}























/*
** The input to this routine is an ExprInfo structure with only the
** "p" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the ExprInfo
** structure.
*/
static void exprAnalyze(ExprMaskSet *pMaskSet, ExprInfo *pInfo){
  Expr *pExpr = pInfo->p;
  pInfo->prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  pInfo->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
  pInfo->prereqAll = exprTableUsage(pMaskSet, pExpr);
  pInfo->indexable = 0;
  pInfo->idxLeft = -1;
  pInfo->idxRight = -1;
  if( allowedOp(pExpr->op) && (pInfo->prereqRight & pInfo->prereqLeft)==0 ){
    if( pExpr->pRight && pExpr->pRight->op==TK_COLUMN ){
      pInfo->idxRight = pExpr->pRight->iTable;
      pInfo->indexable = 1;
    }
    if( pExpr->pLeft->op==TK_COLUMN ){
      pInfo->idxLeft = pExpr->pLeft->iTable;
      pInfo->indexable = 1;
    }
  }


























}

/*
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
** the table has a cursor number of "base".
**







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    case TK_EQ:
    case TK_IN:
      return 1;
    default:
      return 0;
  }
}

/*
** Swap two integers.
*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Return the index in the SrcList that uses cursor iCur.  If iCur is
** used by the first entry in SrcList return 0.  If iCur is used by
** the second entry return 1.  And so forth.
**
** SrcList is the set of tables in the FROM clause in the order that
** they will be processed.  The value returned here gives us an index
** of which tables will be processed first.
*/
static int tableOrder(SrcList *pList, int iCur){
  int i;
  for(i=0; i<pList->nSrc; i++){
    if( pList->a[i].iCursor==iCur ) return i;
  }
  return -1;
}

/*
** The input to this routine is an ExprInfo structure with only the
** "p" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the ExprInfo
** structure.
*/
static void exprAnalyze(SrcList *pSrc, ExprMaskSet *pMaskSet, ExprInfo *pInfo){
  Expr *pExpr = pInfo->p;
  pInfo->prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  pInfo->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
  pInfo->prereqAll = exprTableUsage(pMaskSet, pExpr);
  pInfo->indexable = 0;
  pInfo->idxLeft = -1;
  pInfo->idxRight = -1;
  if( allowedOp(pExpr->op) && (pInfo->prereqRight & pInfo->prereqLeft)==0 ){
    if( pExpr->pRight && pExpr->pRight->op==TK_COLUMN ){
      pInfo->idxRight = pExpr->pRight->iTable;
      pInfo->indexable = 1;
    }
    if( pExpr->pLeft->op==TK_COLUMN ){
      pInfo->idxLeft = pExpr->pLeft->iTable;
      pInfo->indexable = 1;
    }
  }
  if( pInfo->indexable ){
    assert( pInfo->idxLeft!=pInfo->idxRight );

    /* We want the expression to be of the form "X = expr", not "expr = X".
    ** So flip it over if necessary.  If the expression is "X = Y", then
    ** we want Y to come from an earlier table than X.
    **
    ** The collating sequence rule is to always choose the left expression.
    ** So if we do a flip, we also have to move the collating sequence.
    */
    if( tableOrder(pSrc,pInfo->idxLeft)<tableOrder(pSrc,pInfo->idxRight) ){
      assert( pExpr->op!=TK_IN );
      SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl);
      SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
      switch( pExpr->op ){
        case TK_LT:   pExpr->op = TK_GT;  break;
        case TK_LE:   pExpr->op = TK_GE;  break;
        case TK_GT:   pExpr->op = TK_LT;  break;
        case TK_GE:   pExpr->op = TK_LE;  break;
        default:      break;
      }
      SWAP(unsigned, pInfo->prereqLeft, pInfo->prereqRight);
      SWAP(short int, pInfo->idxLeft, pInfo->idxRight);
    }
  }      

}

/*
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
** the table has a cursor number of "base".
**
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  int i;                     /* Loop counter */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  int brk, cont = 0;         /* Addresses used during code generation */
  int nExpr;           /* Number of subexpressions in the WHERE clause */
  int loopMask;        /* One bit set for each outer loop */
  int haveKey = 0;     /* True if KEY is on the stack */

  ExprMaskSet maskSet; /* The expression mask set */
  int iDirectEq[32];   /* Term of the form ROWID==X for the N-th table */
  int iDirectLt[32];   /* Term of the form ROWID<X or ROWID<=X */
  int iDirectGt[32];   /* Term of the form ROWID>X or ROWID>=X */
  ExprInfo aExpr[101]; /* The WHERE clause is divided into these expressions */

  /* pushKey is only allowed if there is a single table (as in an INSERT or
  ** UPDATE statement)
  */
  assert( pushKey==0 || pTabList->nSrc==1 );

  /* Split the WHERE clause into separate subexpressions where each







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  int i;                     /* Loop counter */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  int brk, cont = 0;         /* Addresses used during code generation */
  int nExpr;           /* Number of subexpressions in the WHERE clause */
  int loopMask;        /* One bit set for each outer loop */
  int haveKey = 0;     /* True if KEY is on the stack */
  ExprInfo *pTerm;     /* A single term in the WHERE clause; ptr to aExpr[] */
  ExprMaskSet maskSet; /* The expression mask set */
  int iDirectEq[32];   /* Term of the form ROWID==X for the N-th table */
  int iDirectLt[32];   /* Term of the form ROWID<X or ROWID<=X */
  int iDirectGt[32];   /* Term of the form ROWID>X or ROWID>=X */
  ExprInfo aExpr[101]; /* The WHERE clause is divided into these terms */

  /* pushKey is only allowed if there is a single table (as in an INSERT or
  ** UPDATE statement)
  */
  assert( pushKey==0 || pTabList->nSrc==1 );

  /* Split the WHERE clause into separate subexpressions where each
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  }
  
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
  */
  pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
  if( sqlite3_malloc_failed ){
    sqliteFree(pWInfo);
    return 0;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->peakNTab = pWInfo->savedNTab = pParse->nTab;
  pWInfo->iBreak = sqlite3VdbeMakeLabel(v);

  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstant(pWhere)) ){
    sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
    pWhere = 0;
  }

  /* Analyze all of the subexpressions.
  */
  for(i=0; i<nExpr; i++){

    exprAnalyze(&maskSet, &aExpr[i]);

    /* If we are executing a trigger body, remove all references to
    ** new.* and old.* tables from the prerequisite masks.
    */
    if( pParse->trigStack ){
      int x;
      if( (x = pParse->trigStack->newIdx) >= 0 ){
        int mask = ~getMask(&maskSet, x);
        aExpr[i].prereqRight &= mask;
        aExpr[i].prereqLeft &= mask;
        aExpr[i].prereqAll &= mask;
      }
      if( (x = pParse->trigStack->oldIdx) >= 0 ){
        int mask = ~getMask(&maskSet, x);
        aExpr[i].prereqRight &= mask;
        aExpr[i].prereqLeft &= mask;
        aExpr[i].prereqAll &= mask;
      }
    }
  }

  /* Figure out what index to use (if any) for each nested loop.
  ** Make pWInfo->a[i].pIdx point to the index to use for the i-th nested
  ** loop where i==0 is the outer loop and i==pTabList->nSrc-1 is the inner







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  }
  
  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
  */
  pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
  if( sqlite3_malloc_failed ){
    /* sqliteFree(pWInfo); // Leak memory when malloc fails */
    return 0;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->peakNTab = pWInfo->savedNTab = pParse->nTab;
  pWInfo->iBreak = sqlite3VdbeMakeLabel(v);

  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstant(pWhere)) ){
    sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
    pWhere = 0;
  }

  /* Analyze all of the subexpressions.
  */
  for(pTerm=aExpr, i=0; i<nExpr; i++, pTerm++){
    TriggerStack *pStack;
    exprAnalyze(pTabList, &maskSet, pTerm);

    /* If we are executing a trigger body, remove all references to
    ** new.* and old.* tables from the prerequisite masks.
    */
    if( (pStack = pParse->trigStack)!=0 ){
      int x;
      if( (x=pStack->newIdx) >= 0 ){
        int mask = ~getMask(&maskSet, x);
        pTerm->prereqRight &= mask;
        pTerm->prereqLeft &= mask;
        pTerm->prereqAll &= mask;
      }
      if( (x=pStack->oldIdx) >= 0 ){
        int mask = ~getMask(&maskSet, x);
        pTerm->prereqRight &= mask;
        pTerm->prereqLeft &= mask;
        pTerm->prereqAll &= mask;
      }
    }
  }

  /* Figure out what index to use (if any) for each nested loop.
  ** Make pWInfo->a[i].pIdx point to the index to use for the i-th nested
  ** loop where i==0 is the outer loop and i==pTabList->nSrc-1 is the inner
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    **
    ** (Added:) Treat ROWID IN expr like ROWID=expr.
    */
    pWInfo->a[i].iCur = -1;
    iDirectEq[i] = -1;
    iDirectLt[i] = -1;
    iDirectGt[i] = -1;
    for(j=0; j<nExpr; j++){

      if( aExpr[j].idxLeft==iCur && aExpr[j].p->pLeft->iColumn<0
            && (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
        switch( aExpr[j].p->op ){
          case TK_IN:
          case TK_EQ: iDirectEq[i] = j; break;
          case TK_LE:
          case TK_LT: iDirectLt[i] = j; break;
          case TK_GE:
          case TK_GT: iDirectGt[i] = j;  break;
        }
      }
      if( aExpr[j].idxRight==iCur && aExpr[j].p->pRight->iColumn<0
            && (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
        switch( aExpr[j].p->op ){
          case TK_EQ: iDirectEq[i] = j;  break;
          case TK_LE:
          case TK_LT: iDirectGt[i] = j;  break;
          case TK_GE:
          case TK_GT: iDirectLt[i] = j;  break;
        }
      }
    }
    if( iDirectEq[i]>=0 ){
      loopMask |= mask;
      pWInfo->a[i].pIdx = 0;
      continue;
    }








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    **
    ** (Added:) Treat ROWID IN expr like ROWID=expr.
    */
    pWInfo->a[i].iCur = -1;
    iDirectEq[i] = -1;
    iDirectLt[i] = -1;
    iDirectGt[i] = -1;
    for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
      Expr *pX = pTerm->p;
      if( pTerm->idxLeft==iCur && pX->pLeft->iColumn<0
            && (pTerm->prereqRight & loopMask)==pTerm->prereqRight ){
        switch( pX->op ){
          case TK_IN:
          case TK_EQ: iDirectEq[i] = j; break;
          case TK_LE:
          case TK_LT: iDirectLt[i] = j; break;
          case TK_GE:
          case TK_GT: iDirectGt[i] = j;  break;
        }
      }










    }
    if( iDirectEq[i]>=0 ){
      loopMask |= mask;
      pWInfo->a[i].pIdx = 0;
      continue;
    }

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      int eqMask = 0;  /* Index columns covered by an x=... term */
      int ltMask = 0;  /* Index columns covered by an x<... term */
      int gtMask = 0;  /* Index columns covered by an x>... term */
      int inMask = 0;  /* Index columns covered by an x IN .. term */
      int nEq, m, score;

      if( pIdx->nColumn>32 ) continue;  /* Ignore indices too many columns */
      for(j=0; j<nExpr; j++){
        CollSeq *pColl = sqlite3ExprCollSeq(pParse, aExpr[j].p->pLeft);

        if( !pColl && aExpr[j].p->pRight ){
          pColl = sqlite3ExprCollSeq(pParse, aExpr[j].p->pRight);
        }
        if( !pColl ){
          pColl = pParse->db->pDfltColl;
        }
        if( aExpr[j].idxLeft==iCur 
             && (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
          int iColumn = aExpr[j].p->pLeft->iColumn;
          int k;
          char idxaff = pIdx->pTable->aCol[iColumn].affinity; 
          for(k=0; k<pIdx->nColumn; k++){
            /* If the collating sequences or affinities don't match, 
            ** ignore this index.  */
            if( pColl!=pIdx->keyInfo.aColl[k] ) continue;
            if( !sqlite3IndexAffinityOk(aExpr[j].p, idxaff) ) continue;
            if( pIdx->aiColumn[k]==iColumn ){
              switch( aExpr[j].p->op ){
                case TK_IN: {
                  if( k==0 ) inMask |= 1;
                  break;
                }
                case TK_EQ: {
                  eqMask |= 1<<k;
                  break;
                }
                case TK_LE:
                case TK_LT: {
                  ltMask |= 1<<k;
                  break;
                }
                case TK_GE:
                case TK_GT: {
                  gtMask |= 1<<k;
                  break;
                }
                default: {
                  /* CANT_HAPPEN */
                  assert( 0 );
                  break;
                }
              }
              break;
            }
          }
        }
        if( aExpr[j].idxRight==iCur 
             && (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
          int iColumn = aExpr[j].p->pRight->iColumn;
          int k;
          char idxaff = pIdx->pTable->aCol[iColumn].affinity; 
          for(k=0; k<pIdx->nColumn; k++){
            /* If the collating sequences or affinities don't match, 
            ** ignore this index.  */
            if( pColl!=pIdx->keyInfo.aColl[k] ) continue;
            if( !sqlite3IndexAffinityOk(aExpr[j].p, idxaff) ) continue;
            if( pIdx->aiColumn[k]==iColumn ){
              switch( aExpr[j].p->op ){
                case TK_EQ: {
                  eqMask |= 1<<k;
                  break;
                }
                case TK_LE:
                case TK_LT: {
                  gtMask |= 1<<k;
                  break;
                }
                case TK_GE:
                case TK_GT: {
                  ltMask |= 1<<k;
                  break;
                }
                default: {
                  /* CANT_HAPPEN */
                  assert( 0 );
                  break;
                }
              }
              break;







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      int eqMask = 0;  /* Index columns covered by an x=... term */
      int ltMask = 0;  /* Index columns covered by an x<... term */
      int gtMask = 0;  /* Index columns covered by an x>... term */
      int inMask = 0;  /* Index columns covered by an x IN .. term */
      int nEq, m, score;

      if( pIdx->nColumn>32 ) continue;  /* Ignore indices too many columns */
      for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
        CollSeq *pColl = sqlite3ExprCollSeq(pParse, pTerm->p->pLeft);
        Expr *pX = pTerm->p;
        if( !pColl && pX->pRight ){
          pColl = sqlite3ExprCollSeq(pParse, pX->pRight);
        }
        if( !pColl ){
          pColl = pParse->db->pDfltColl;
        }
        if( pTerm->idxLeft==iCur 
             && (pTerm->prereqRight & loopMask)==pTerm->prereqRight ){
          int iColumn = pX->pLeft->iColumn;
          int k;
          char idxaff = pIdx->pTable->aCol[iColumn].affinity; 
          for(k=0; k<pIdx->nColumn; k++){
            /* If the collating sequences or affinities don't match, 
            ** ignore this index.  */
            if( pColl!=pIdx->keyInfo.aColl[k] ) continue;
            if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue;
            if( pIdx->aiColumn[k]==iColumn ){
              switch( pX->op ){
                case TK_IN: {
                  if( k==0 ) inMask |= 1;
                  break;
                }
                case TK_EQ: {
                  eqMask |= 1<<k;
                  break;
                }
                case TK_LE:
                case TK_LT: {
                  ltMask |= 1<<k;
                  break;
                }
                case TK_GE:
                case TK_GT: {
                  gtMask |= 1<<k;
                  break;
                }




































                default: {
                  /* CANT_HAPPEN */
                  assert( 0 );
                  break;
                }
              }
              break;
766
767
768
769
770
771
772

773
774
775

776
777

778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823

824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
    pLevel->inOp = OP_Noop;
    if( i<ARRAYSIZE(iDirectEq) && iDirectEq[i]>=0 ){
      /* Case 1:  We can directly reference a single row using an
      **          equality comparison against the ROWID field.  Or
      **          we reference multiple rows using a "rowid IN (...)"
      **          construct.
      */

      k = iDirectEq[i];
      assert( k<nExpr );
      assert( aExpr[k].p!=0 );

      assert( aExpr[k].idxLeft==iCur || aExpr[k].idxRight==iCur );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

      if( aExpr[k].idxLeft==iCur ){
        Expr *pX = aExpr[k].p;
        if( pX->op!=TK_IN ){
          sqlite3ExprCode(pParse, aExpr[k].p->pRight);
        }else{
          sqlite3VdbeAddOp(v, OP_Rewind, pX->iTable, brk);
          sqlite3VdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
          pLevel->inP2 = sqlite3VdbeAddOp(v, OP_IdxColumn, pX->iTable, 0);
          pLevel->inOp = OP_Next;
          pLevel->inP1 = pX->iTable;
        }
      }else{
        sqlite3ExprCode(pParse, aExpr[k].p->pLeft);
      }
      disableTerm(pLevel, &aExpr[k].p);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk);
      haveKey = 0;
      sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk);
      pLevel->op = OP_Noop;
    }else if( pIdx!=0 && pLevel->score>0 && pLevel->score%4==0 ){
      /* Case 2:  There is an index and all terms of the WHERE clause that
      **          refer to the index use the "==" or "IN" operators.
      */
      int start;
      int nColumn = (pLevel->score+4)/8;
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

      /* For each column of the index, find the term of the WHERE clause that
      ** constraints that column.  If the WHERE clause term is X=expr, then
      ** evaluation expr and leave the result on the stack */
      for(j=0; j<nColumn; j++){
        for(k=0; k<nExpr; k++){
          Expr *pX = aExpr[k].p;
          if( pX==0 ) continue;
          if( aExpr[k].idxLeft==iCur
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pX->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            char idxaff = pIdx->pTable->aCol[pX->pLeft->iColumn].affinity;
            if( sqlite3IndexAffinityOk(aExpr[k].p, idxaff) ){
              if( pX->op==TK_EQ ){
                sqlite3ExprCode(pParse, pX->pRight);
                disableTerm(pLevel, &aExpr[k].p);
                break;
              }

              if( pX->op==TK_IN && nColumn==1 ){
                sqlite3VdbeAddOp(v, OP_Rewind, pX->iTable, brk);
                sqlite3VdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
                pLevel->inP2 = sqlite3VdbeAddOp(v, OP_IdxColumn, pX->iTable, 0);
                pLevel->inOp = OP_Next;
                pLevel->inP1 = pX->iTable;
                disableTerm(pLevel, &aExpr[k].p);
                break;
              }
            }
          }
          if( aExpr[k].idxRight==iCur
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            char idxaff = pIdx->pTable->aCol[pX->pRight->iColumn].affinity;
            if( sqlite3IndexAffinityOk(aExpr[k].p, idxaff) ){
              sqlite3ExprCode(pParse, aExpr[k].p->pLeft);
              disableTerm(pLevel, &aExpr[k].p);
              break;
            }
          }
        }
      }
      pLevel->iMem = pParse->nMem++;
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);








>


|
>
|

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

















|
|

|
|



|


|


>






|


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







772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787

788
789
790
791
792
793
794
795
796



797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838












839
840
841
842
843
844
845
    pLevel->inOp = OP_Noop;
    if( i<ARRAYSIZE(iDirectEq) && iDirectEq[i]>=0 ){
      /* Case 1:  We can directly reference a single row using an
      **          equality comparison against the ROWID field.  Or
      **          we reference multiple rows using a "rowid IN (...)"
      **          construct.
      */
      Expr *pX;
      k = iDirectEq[i];
      assert( k<nExpr );
      pTerm = &aExpr[k];
      assert( pTerm->p!=0 );
      assert( pTerm->idxLeft==iCur || pTerm->idxRight==iCur );
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      pX = pTerm->p;
      assert( pTerm->idxLeft==iCur );

      if( pX->op!=TK_IN ){
        sqlite3ExprCode(pParse, pTerm->p->pRight);
      }else{
        sqlite3VdbeAddOp(v, OP_Rewind, pX->iTable, brk);
        sqlite3VdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
        pLevel->inP2 = sqlite3VdbeAddOp(v, OP_IdxColumn, pX->iTable, 0);
        pLevel->inOp = OP_Next;
        pLevel->inP1 = pX->iTable;
      }



      disableTerm(pLevel, &pTerm->p);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk);
      haveKey = 0;
      sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk);
      pLevel->op = OP_Noop;
    }else if( pIdx!=0 && pLevel->score>0 && pLevel->score%4==0 ){
      /* Case 2:  There is an index and all terms of the WHERE clause that
      **          refer to the index use the "==" or "IN" operators.
      */
      int start;
      int nColumn = (pLevel->score+4)/8;
      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);

      /* For each column of the index, find the term of the WHERE clause that
      ** constraints that column.  If the WHERE clause term is X=expr, then
      ** evaluation expr and leave the result on the stack */
      for(j=0; j<nColumn; j++){
        for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
          Expr *pX = pTerm->p;
          if( pX==0 ) continue;
          if( pTerm->idxLeft==iCur
             && (pTerm->prereqRight & loopMask)==pTerm->prereqRight 
             && pX->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            char idxaff = pIdx->pTable->aCol[pX->pLeft->iColumn].affinity;
            if( sqlite3IndexAffinityOk(pTerm->p, idxaff) ){
              if( pX->op==TK_EQ ){
                sqlite3ExprCode(pParse, pX->pRight);
                disableTerm(pLevel, &pTerm->p);
                break;
              }
              assert( pX->op==TK_IN && nColumn==1 );
              if( pX->op==TK_IN && nColumn==1 ){
                sqlite3VdbeAddOp(v, OP_Rewind, pX->iTable, brk);
                sqlite3VdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
                pLevel->inP2 = sqlite3VdbeAddOp(v, OP_IdxColumn, pX->iTable, 0);
                pLevel->inOp = OP_Next;
                pLevel->inP1 = pX->iTable;
                disableTerm(pLevel, &pTerm->p);
                break;
              }












            }
          }
        }
      }
      pLevel->iMem = pParse->nMem++;
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);

898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
      int start;

      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( iDirectGt[i]>=0 ){
        k = iDirectGt[i];
        assert( k<nExpr );
        assert( aExpr[k].p!=0 );
        assert( aExpr[k].idxLeft==iCur || aExpr[k].idxRight==iCur );
        if( aExpr[k].idxLeft==iCur ){
          sqlite3ExprCode(pParse, aExpr[k].p->pRight);
        }else{
          sqlite3ExprCode(pParse, aExpr[k].p->pLeft);
        }
        sqlite3VdbeAddOp(v, OP_ForceInt,
          aExpr[k].p->op==TK_LT || aExpr[k].p->op==TK_GT, brk);
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, brk);
        disableTerm(pLevel, &aExpr[k].p);
      }else{
        sqlite3VdbeAddOp(v, OP_Rewind, iCur, brk);
      }
      if( iDirectLt[i]>=0 ){
        k = iDirectLt[i];
        assert( k<nExpr );
        assert( aExpr[k].p!=0 );
        assert( aExpr[k].idxLeft==iCur || aExpr[k].idxRight==iCur );
        if( aExpr[k].idxLeft==iCur ){
          sqlite3ExprCode(pParse, aExpr[k].p->pRight);
        }else{
          sqlite3ExprCode(pParse, aExpr[k].p->pLeft);
        }
        /* sqlite3VdbeAddOp(v, OP_MustBeInt, 0, sqlite3VdbeCurrentAddr(v)+1); */
        pLevel->iMem = pParse->nMem++;
        sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
        if( aExpr[k].p->op==TK_LT || aExpr[k].p->op==TK_GT ){
          testOp = OP_Ge;
        }else{
          testOp = OP_Gt;
        }
        disableTerm(pLevel, &aExpr[k].p);
      }
      start = sqlite3VdbeCurrentAddr(v);
      pLevel->op = OP_Next;
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);







|
|
|
<
<
|
<

|

|






|
|
|
<
<
|
<



|




|







892
893
894
895
896
897
898
899
900
901


902

903
904
905
906
907
908
909
910
911
912
913
914
915


916

917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
      int start;

      brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
      cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
      if( iDirectGt[i]>=0 ){
        k = iDirectGt[i];
        assert( k<nExpr );
        pTerm = &aExpr[k];
        assert( pTerm->p!=0 );
        assert( pTerm->idxLeft==iCur );


        sqlite3ExprCode(pParse, pTerm->p->pRight);

        sqlite3VdbeAddOp(v, OP_ForceInt,
          pTerm->p->op==TK_LT || pTerm->p->op==TK_GT, brk);
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, brk);
        disableTerm(pLevel, &pTerm->p);
      }else{
        sqlite3VdbeAddOp(v, OP_Rewind, iCur, brk);
      }
      if( iDirectLt[i]>=0 ){
        k = iDirectLt[i];
        assert( k<nExpr );
        pTerm = &aExpr[k];
        assert( pTerm->p!=0 );
        assert( pTerm->idxLeft==iCur );


        sqlite3ExprCode(pParse, pTerm->p->pRight);

        /* sqlite3VdbeAddOp(v, OP_MustBeInt, 0, sqlite3VdbeCurrentAddr(v)+1); */
        pLevel->iMem = pParse->nMem++;
        sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
        if( pTerm->p->op==TK_LT || pTerm->p->op==TK_GT ){
          testOp = OP_Ge;
        }else{
          testOp = OP_Gt;
        }
        disableTerm(pLevel, &pTerm->p);
      }
      start = sqlite3VdbeCurrentAddr(v);
      pLevel->op = OP_Next;
      pLevel->p1 = iCur;
      pLevel->p2 = start;
      if( testOp!=OP_Noop ){
        sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
      int start;
      int leFlag=0, geFlag=0;
      int testOp;

      /* Evaluate the equality constraints
      */
      for(j=0; j<nEqColumn; j++){
        for(k=0; k<nExpr; k++){
          if( aExpr[k].p==0 ) continue;
          if( aExpr[k].idxLeft==iCur
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && aExpr[k].p->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, aExpr[k].p->pRight);
            disableTerm(pLevel, &aExpr[k].p);
            break;
          }
          if( aExpr[k].idxRight==iCur
             && aExpr[k].p->op==TK_EQ
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, aExpr[k].p->pLeft);
            disableTerm(pLevel, &aExpr[k].p);
            break;
          }
        }
      }

      /* Duplicate the equality term values because they will all be
      ** used twice: once to make the termination key and once to make the







|
|
|
|
|
|

<
<
<
<
<
<
<
<
<
|
|







965
966
967
968
969
970
971
972
973
974
975
976
977
978









979
980
981
982
983
984
985
986
987
      int start;
      int leFlag=0, geFlag=0;
      int testOp;

      /* Evaluate the equality constraints
      */
      for(j=0; j<nEqColumn; j++){
        for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
          if( pTerm->p==0 ) continue;
          if( pTerm->idxLeft==iCur
             && pTerm->p->op==TK_EQ
             && (pTerm->prereqRight & loopMask)==pTerm->prereqRight 
             && pTerm->p->pLeft->iColumn==pIdx->aiColumn[j]
          ){









            sqlite3ExprCode(pParse, pTerm->p->pRight);
            disableTerm(pLevel, &pTerm->p);
            break;
          }
        }
      }

      /* Duplicate the equality term values because they will all be
      ** used twice: once to make the termination key and once to make the
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
      ** will end the search.  There is no termination key if there
      ** are no equality terms and no "X<..." term.
      **
      ** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
      ** key computed here really ends up being the start key.
      */
      if( (score & 1)!=0 ){
        for(k=0; k<nExpr; k++){
          Expr *pExpr = aExpr[k].p;
          if( pExpr==0 ) continue;
          if( aExpr[k].idxLeft==iCur
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, pExpr->pRight);
            leFlag = pExpr->op==TK_LE;
            disableTerm(pLevel, &aExpr[k].p);
            break;
          }
          if( aExpr[k].idxRight==iCur
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && pExpr->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, pExpr->pLeft);
            leFlag = pExpr->op==TK_GE;
            disableTerm(pLevel, &aExpr[k].p);
            break;
          }
        }
        testOp = OP_IdxGE;
      }else{
        testOp = nEqColumn>0 ? OP_IdxGE : OP_Noop;
        leFlag = 1;







|
|

|

|




|
<
<
<
<
<
<
<
<
<
<







1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017










1018
1019
1020
1021
1022
1023
1024
      ** will end the search.  There is no termination key if there
      ** are no equality terms and no "X<..." term.
      **
      ** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
      ** key computed here really ends up being the start key.
      */
      if( (score & 1)!=0 ){
        for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
          Expr *pExpr = pTerm->p;
          if( pExpr==0 ) continue;
          if( pTerm->idxLeft==iCur
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (pTerm->prereqRight & loopMask)==pTerm->prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, pExpr->pRight);
            leFlag = pExpr->op==TK_LE;
            disableTerm(pLevel, &pTerm->p);










            break;
          }
        }
        testOp = OP_IdxGE;
      }else{
        testOp = nEqColumn>0 ? OP_IdxGE : OP_Noop;
        leFlag = 1;
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
1106
1107
1108
1109
1110
1111
1112
      ** that case, generate a "Rewind" instruction in place of the
      ** start key search.
      **
      ** 2002-Dec-04: In the case of a reverse-order search, the so-called
      ** "start" key really ends up being used as the termination key.
      */
      if( (score & 2)!=0 ){
        for(k=0; k<nExpr; k++){
          Expr *pExpr = aExpr[k].p;
          if( pExpr==0 ) continue;
          if( aExpr[k].idxLeft==iCur
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, pExpr->pRight);
            geFlag = pExpr->op==TK_GE;
            disableTerm(pLevel, &aExpr[k].p);
            break;
          }
          if( aExpr[k].idxRight==iCur
             && (pExpr->op==TK_LT || pExpr->op==TK_LE)
             && (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
             && pExpr->pRight->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, pExpr->pLeft);
            geFlag = pExpr->op==TK_LE;
            disableTerm(pLevel, &aExpr[k].p);
            break;
          }
        }
      }else{
        geFlag = 1;
      }
      if( nEqColumn>0 || (score&2)!=0 ){







|
|

|

|




|
<
<
<
<
<
<
<
<
<
<







1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064










1065
1066
1067
1068
1069
1070
1071
      ** that case, generate a "Rewind" instruction in place of the
      ** start key search.
      **
      ** 2002-Dec-04: In the case of a reverse-order search, the so-called
      ** "start" key really ends up being used as the termination key.
      */
      if( (score & 2)!=0 ){
        for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
          Expr *pExpr = pTerm->p;
          if( pExpr==0 ) continue;
          if( pTerm->idxLeft==iCur
             && (pExpr->op==TK_GT || pExpr->op==TK_GE)
             && (pTerm->prereqRight & loopMask)==pTerm->prereqRight 
             && pExpr->pLeft->iColumn==pIdx->aiColumn[j]
          ){
            sqlite3ExprCode(pParse, pExpr->pRight);
            geFlag = pExpr->op==TK_GE;
            disableTerm(pLevel, &pTerm->p);










            break;
          }
        }
      }else{
        geFlag = 1;
      }
      if( nEqColumn>0 || (score&2)!=0 ){
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
      pLevel->p2 = start;
    }
    loopMask |= getMask(&maskSet, iCur);

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(j=0; j<nExpr; j++){
      if( aExpr[j].p==0 ) continue;
      if( (aExpr[j].prereqAll & loopMask)!=aExpr[j].prereqAll ) continue;
      if( pLevel->iLeftJoin && !ExprHasProperty(aExpr[j].p,EP_FromJoin) ){
        continue;
      }
      if( haveKey ){
        haveKey = 0;
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
      }
      sqlite3ExprIfFalse(pParse, aExpr[j].p, cont, 1);
      aExpr[j].p = 0;
    }
    brk = cont;

    /* For a LEFT OUTER JOIN, generate code that will record the fact that
    ** at least one row of the right table has matched the left table.  
    */
    if( pLevel->iLeftJoin ){
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      for(j=0; j<nExpr; j++){
        if( aExpr[j].p==0 ) continue;
        if( (aExpr[j].prereqAll & loopMask)!=aExpr[j].prereqAll ) continue;
        if( haveKey ){
          /* Cannot happen.  "haveKey" can only be true if pushKey is true
          ** an pushKey can only be true for DELETE and UPDATE and there are
          ** no outer joins with DELETE and UPDATE.
          */
          haveKey = 0;
          sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        }
        sqlite3ExprIfFalse(pParse, aExpr[j].p, cont, 1);
        aExpr[j].p = 0;
      }
    }
  }
  pWInfo->iContinue = cont;
  if( pushKey && !haveKey ){
    sqlite3VdbeAddOp(v, OP_Recno, pTabList->a[0].iCursor, 0);
  }







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|






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|
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|
|







1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
      pLevel->p2 = start;
    }
    loopMask |= getMask(&maskSet, iCur);

    /* Insert code to test every subexpression that can be completely
    ** computed using the current set of tables.
    */
    for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
      if( pTerm->p==0 ) continue;
      if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
      if( pLevel->iLeftJoin && !ExprHasProperty(pTerm->p,EP_FromJoin) ){
        continue;
      }
      if( haveKey ){
        haveKey = 0;
        sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
      }
      sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
      pTerm->p = 0;
    }
    brk = cont;

    /* For a LEFT OUTER JOIN, generate code that will record the fact that
    ** at least one row of the right table has matched the left table.  
    */
    if( pLevel->iLeftJoin ){
      pLevel->top = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
      for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
        if( pTerm->p==0 ) continue;
        if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
        if( haveKey ){
          /* Cannot happen.  "haveKey" can only be true if pushKey is true
          ** an pushKey can only be true for DELETE and UPDATE and there are
          ** no outer joins with DELETE and UPDATE.
          */
          haveKey = 0;
          sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
        }
        sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
        pTerm->p = 0;
      }
    }
  }
  pWInfo->iContinue = cont;
  if( pushKey && !haveKey ){
    sqlite3VdbeAddOp(v, OP_Recno, pTabList->a[0].iCursor, 0);
  }