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Prevent an automatic index from taking the place of a declared index.

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FossilOrigin-Name: 0a52bddd9db49b2b79fc24888b50023d0fe74f7b
This commit is contained in:
drh
2014-06-18 15:11:54 +00:00
parent ef3ad02d90 dabe36d9dd
commit f9944b5053
4 changed files with 79 additions and 8 deletions
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13
src/where.c
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@@ -3923,6 +3923,17 @@ static WhereLoop **whereLoopFindLesser(
** rSetup. Call this SETUP-INVARIANT */
assert( p->rSetup>=pTemplate->rSetup );
/* Any loop using an appliation-defined index (or PRIMARY KEY or
** UNIQUE constraint) with one or more == constraints is better
** than an automatic index. */
if( (p->wsFlags & WHERE_AUTO_INDEX)!=0
&& (pTemplate->wsFlags & WHERE_INDEXED)!=0
&& (pTemplate->wsFlags & WHERE_COLUMN_EQ)!=0
&& (p->prereq & pTemplate->prereq)==pTemplate->prereq
){
break;
}
/* If existing WhereLoop p is better than pTemplate, pTemplate can be
** discarded. WhereLoop p is better if:
** (1) p has no more dependencies than pTemplate, and
@@ -4047,7 +4058,7 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
WhereLoop *pToDel;
while( *ppTail ){
ppTail = whereLoopFindLesser(ppTail, pTemplate);
if( NEVER(ppTail==0) ) break;
if( ppTail==0 ) break;
pToDel = *ppTail;
if( pToDel==0 ) break;
*ppTail = pToDel->pNextLoop;