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Provide hints for all terms in a range constraint if there are any equality

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terms anywhere in the constraint.  Range constraint terms are only omitted
for a pure range constraint with no equality prefix.

FossilOrigin-Name: b5897bc0f003c470eeb2a75e0a2b2bb202681531
This commit is contained in:
drh
2015-08-18 15:58:05 +00:00
parent b413a5467a
commit bcf40a7f12
4 changed files with 29 additions and 26 deletions
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31
src/wherecode.c
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@@ -681,7 +681,6 @@ static void codeCursorHint(
int iCur;
WhereClause *pWC;
WhereTerm *pTerm;
WhereLoop *pWLoop;
int i, j;
struct CCurHint sHint;
Walker sWalker;
@@ -696,7 +695,6 @@ static void codeCursorHint(
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;
@@ -704,10 +702,11 @@ static void codeCursorHint(
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;
** 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 */
@@ -1094,15 +1093,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
}
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).
@@ -1114,6 +1104,16 @@ Bitmask sqlite3WhereCodeOneLoopStart(
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 );
@@ -1123,7 +1123,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
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;