SQLite

Check-in [b5897bc0f0]
Login

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

Overview
Comment:Provide hints for all terms in a range constraint if there are any equality terms anywhere in the constraint. Range constraint terms are only omitted for a pure range constraint with no equality prefix.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | cursor-hints
Files: files | file ages | folders
SHA1: b5897bc0f003c470eeb2a75e0a2b2bb202681531
User & Date: drh 2015-08-18 15:58:05.895
Context
2015-08-20
23:45
Merge recent enhancements from trunk, including table-valued expressions. (check-in: b9927c876c user: drh tags: cursor-hints)
2015-08-18
15:58
Provide hints for all terms in a range constraint if there are any equality terms anywhere in the constraint. Range constraint terms are only omitted for a pure range constraint with no equality prefix. (check-in: b5897bc0f0 user: drh tags: cursor-hints)
2015-08-17
17:19
Avoid generating hints using constraints that are also used to initialize the cursor, since presumably the cursor already knows about those constraints. (check-in: 142b048ac7 user: drh tags: cursor-hints)
Changes
Unified Diff Show Whitespace Changes Patch
Changes to src/wherecode.c.
︙︙
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707

708
709
710
711
712
713
714
715
716
717

  sqlite3 *db = pParse->db;
  Vdbe *v = pParse->pVdbe;
  Expr *pExpr = 0;
  WhereLoop *pLoop = pLevel->pWLoop;
  int iCur;
  WhereClause *pWC;
  WhereTerm *pTerm;
  WhereLoop *pWLoop;
  int i, j;
  struct CCurHint sHint;
  Walker sWalker;

  if( OptimizationDisabled(db, SQLITE_CursorHints) ) return;
  iCur = pLevel->iTabCur;
  assert( iCur==pWInfo->pTabList->a[pLevel->iFrom].iCursor );
  sHint.iTabCur = iCur;
  sHint.iIdxCur = pLevel->iIdxCur;
  sHint.pIdx = pLoop->u.btree.pIndex;
  memset(&sWalker, 0, sizeof(sWalker));
  sWalker.pParse = pParse;
  sWalker.u.pCCurHint = &sHint;
  pWC = &pWInfo->sWC;
  pWLoop = pLevel->pWLoop;
  for(i=0; i<pWC->nTerm; i++){
    pTerm = &pWC->a[i];
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( pTerm->prereqAll & pLevel->notReady ) continue;
    if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) continue;

    /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize
    ** the cursor.  No need to hint initialization terms. */

    if( pTerm!=pEndRange ){
      for(j=0; j<pWLoop->nLTerm && pWLoop->aLTerm[j]!=pTerm; j++){}
      if( j<pWLoop->nLTerm ) continue;
    }

    /* No subqueries or non-deterministic functions allowed */
    if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue;

    /* For an index scan, make sure referenced columns are actually in
    ** the index. */








<














<







|
>
|
|
|








677
678
679
680
681
682
683

684
685
686
687
688
689
690
691
692
693
694
695
696
697

698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716

  sqlite3 *db = pParse->db;
  Vdbe *v = pParse->pVdbe;
  Expr *pExpr = 0;
  WhereLoop *pLoop = pLevel->pWLoop;
  int iCur;
  WhereClause *pWC;
  WhereTerm *pTerm;

  int i, j;
  struct CCurHint sHint;
  Walker sWalker;

  if( OptimizationDisabled(db, SQLITE_CursorHints) ) return;
  iCur = pLevel->iTabCur;
  assert( iCur==pWInfo->pTabList->a[pLevel->iFrom].iCursor );
  sHint.iTabCur = iCur;
  sHint.iIdxCur = pLevel->iIdxCur;
  sHint.pIdx = pLoop->u.btree.pIndex;
  memset(&sWalker, 0, sizeof(sWalker));
  sWalker.pParse = pParse;
  sWalker.u.pCCurHint = &sHint;
  pWC = &pWInfo->sWC;

  for(i=0; i<pWC->nTerm; i++){
    pTerm = &pWC->a[i];
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( pTerm->prereqAll & pLevel->notReady ) continue;
    if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) continue;

    /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize
    ** the cursor.  These terms are not needed as hints for a pure range
    ** scan (that has no == terms) so omit them. */
    if( pLoop->u.btree.nEq==0 && pTerm!=pEndRange ){
      for(j=0; j<pLoop->nLTerm && pLoop->aLTerm[j]!=pTerm; j++){}
      if( j<pLoop->nLTerm ) continue;
    }

    /* No subqueries or non-deterministic functions allowed */
    if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue;

    /* For an index scan, make sure referenced columns are actually in
    ** the index. */
︙︙
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115










1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133

       && pIdx->pTable->aCol[j].notNull==0
      ){
        bSeekPastNull = 1;
      }
    }
    assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase.
    */
    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
    assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
    if( zStartAff ) cEndAff = zStartAff[nEq];
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( (nEq<pIdx->nKeyCol && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC))
     || (bRev && pIdx->nKeyCol==nEq)
    ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
      SWAP(u8, bSeekPastNull, bStopAtNull);
    }











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

    /* Seek the index cursor to the start of the range. */
    codeCursorHint(pWInfo, pLevel, pRangeEnd);
    nConstraint = nEq;
    if( pRangeStart ){
      Expr *pRight = pRangeStart->pExpr->pRight;
      sqlite3ExprCode(pParse, pRight, regBase+nEq);
      whereLikeOptimizationStringFixup(v, pLevel, pRangeStart);
      if( (pRangeStart->wtFlags & TERM_VNULL)==0
       && sqlite3ExprCanBeNull(pRight)








<
<
<
<
<
<
<
<
<










>
>
>
>
>
>
>
>
>
>










<








1089
1090
1091
1092
1093
1094
1095









1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125

1126
1127
1128
1129
1130
1131
1132

       && pIdx->pTable->aCol[j].notNull==0
      ){
        bSeekPastNull = 1;
      }
    }
    assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );










    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( (nEq<pIdx->nKeyCol && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC))
     || (bRev && pIdx->nKeyCol==nEq)
    ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
      SWAP(u8, bSeekPastNull, bStopAtNull);
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase.
    */
    codeCursorHint(pWInfo, pLevel, pRangeEnd);
    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
    assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
    if( zStartAff ) cEndAff = zStartAff[nEq];
    addrNxt = pLevel->addrNxt;

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

    /* Seek the index cursor to the start of the range. */

    nConstraint = nEq;
    if( pRangeStart ){
      Expr *pRight = pRangeStart->pExpr->pRight;
      sqlite3ExprCode(pParse, pRight, regBase+nEq);
      whereLikeOptimizationStringFixup(v, pLevel, pRangeStart);
      if( (pRangeStart->wtFlags & TERM_VNULL)==0
       && sqlite3ExprCanBeNull(pRight)
︙︙
Changes to test/cursorhint.test.
︙︙
135
136
137
138
139
140
141




142
143
144
145
146
147
148
149
150
151
152
153

  }
} {LE(c0,20)}
do_test 4.5desc {
  p4_of_opcode db CursorHint {
    SELECT c FROM t1 WHERE b>=10 AND b<=20 ORDER BY b DESC;
  }
} {GE(c0,10)}




do_test 4.6asc {
  p4_of_opcode db CursorHint {
    SELECT rowid FROM t1 WHERE b=22 AND c>=10 AND c<=20 ORDER BY b,c ASC;
  }
} {LE(c1,20)}
do_test 4.6desc {
  p4_of_opcode db CursorHint {
    SELECT rowid FROM t1 WHERE b=22 AND c>=10 AND c<=20 ORDER BY b,c DESC;
  }
} {GE(c1,10)}

finish_test








>
>
>
>




|




|



135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

  }
} {LE(c0,20)}
do_test 4.5desc {
  p4_of_opcode db CursorHint {
    SELECT c FROM t1 WHERE b>=10 AND b<=20 ORDER BY b DESC;
  }
} {GE(c0,10)}

# If there are any equality terms used in the constraint, then all terms
# should be hinted.
#
do_test 4.6asc {
  p4_of_opcode db CursorHint {
    SELECT rowid FROM t1 WHERE b=22 AND c>=10 AND c<=20 ORDER BY b,c ASC;
  }
} {AND(AND(EQ(c0,22),GE(c1,10)),LE(c1,20))}
do_test 4.6desc {
  p4_of_opcode db CursorHint {
    SELECT rowid FROM t1 WHERE b=22 AND c>=10 AND c<=20 ORDER BY b,c DESC;
  }
} {AND(AND(EQ(c0,22),GE(c1,10)),LE(c1,20))}

finish_test