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In the automatic index generator logic, be more precise about when a

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partial automatic index is allowed in order to capture more cases where it
is legal to use a partial automatic index.

FossilOrigin-Name: 664b461bb5063d98047fc2e51a3827235cd9f55ca2e23cb66e719eac53fb5437
This commit is contained in:
drh
2021-11-30 14:07:58 +00:00
parent 78679a4950
commit c1085ea412
4 changed files with 108 additions and 16 deletions
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14
src/where.c
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@@ -791,13 +791,13 @@ static void constructAutomaticIndex(
idxCols = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
Expr *pExpr = pTerm->pExpr;
assert( !ExprHasProperty(pExpr, EP_FromJoin) /* prereq always non-zero */
|| pExpr->iRightJoinTable!=pSrc->iCursor /* for the right-hand */
|| pLoop->prereq!=0 ); /* table of a LEFT JOIN */
if( pLoop->prereq==0
&& (pTerm->wtFlags & TERM_VIRTUAL)==0
&& !ExprHasProperty(pExpr, EP_FromJoin)
&& sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor) ){
/* Make the automatic index a partial index if there are terms in the
** WHERE clause (or the ON clause of a LEFT join) that constrain which
** rows of the target table (pSrc) that can be used. */
if( (pTerm->wtFlags & TERM_VIRTUAL)==0
&& ((pSrc->fg.jointype&JT_LEFT)==0 || ExprHasProperty(pExpr,EP_FromJoin))
&& sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor)
){
pPartial = sqlite3ExprAnd(pParse, pPartial,
sqlite3ExprDup(pParse->db, pExpr, 0));
}