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As evidenced by [forum:/forumpost/f3f546025a|forum post f3f546025a], the

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new RIGHT JOIN related restriction on the push-down optimization implemented
by [da3fba18742b6e0b] also needs to apply to the automatic index
(a.k.a. hash-join) optimization and to the Bloom filter optimization.
Computation of the restriction is now
moved into the sqlite3ExprIsSingleTableConstraint() routine.

FossilOrigin-Name: 4902015dcf3869f08d9986e422faa231d9218a5e0fc59ba8df0f407e4eb3d605
This commit is contained in:
drh
2023-05-15 02:06:35 +00:00
parent fa746af4a3
commit eb4455e4e4
7 changed files with 84 additions and 26 deletions
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44
src/expr.c
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@@ -2378,10 +2378,11 @@ int sqlite3ExprIsTableConstant(Expr *p, int iCur){
}
/*
** Check pExpr to see if it is an constraint on the single data source pSrc.
** In other words, check to see if pExpr constrains pSrc but does not depend
** on any other tables or data sources anywhere else in the query. Return
** true (non-zero) if pExpr is a constraint on pSrc only.
** Check pExpr to see if it is an constraint on the single data source
** pSrc = &pSrcList->a[iSrc]. In other words, check to see if pExpr
** constrains pSrc but does not depend on any other tables or data
** sources anywhere else in the query. Return true (non-zero) if pExpr
** is a constraint on pSrc only.
**
** This is an optimization. False negatives will perhaps cause slower
** queries, but false positives will yield incorrect answers. So when in
@@ -2398,13 +2399,31 @@ int sqlite3ExprIsTableConstant(Expr *p, int iCur){
**
** (4) If pSrc is the right operand of a LEFT JOIN, then...
** (4a) pExpr must come from an ON clause..
(4b) and specifically the ON clause associated with the LEFT JOIN.
** (4b) and specifically the ON clause associated with the LEFT JOIN.
**
** (5) If pSrc is not the right operand of a LEFT JOIN or the left
** operand of a RIGHT JOIN, then pExpr must be from the WHERE
** clause, not an ON clause.
**
** (6) Either:
**
** (6a) pExpr does not originate in an ON or USING clause, or
**
** (6b) The ON or USING clause from which pExpr is derived is
** not to the left of a RIGHT JOIN (or FULL JOIN).
**
** Without this restriction, accepting pExpr as a single-table
** constraint might move the the ON/USING filter expression
** from the left side of a RIGHT JOIN over to the right side,
** which leads to incorrect answers. See also restriction (9)
** on push-down.
*/
int sqlite3ExprIsSingleTableConstraint(Expr *pExpr, const SrcItem *pSrc){
int sqlite3ExprIsSingleTableConstraint(
Expr *pExpr, /* The constraint */
const SrcList *pSrcList, /* Complete FROM clause */
int iSrc /* Which element of pSrcList to use */
){
const SrcItem *pSrc = &pSrcList->a[iSrc];
if( pSrc->fg.jointype & JT_LTORJ ){
return 0; /* rule (3) */
}
@@ -2414,6 +2433,19 @@ int sqlite3ExprIsSingleTableConstraint(Expr *pExpr, const SrcItem *pSrc){
}else{
if( ExprHasProperty(pExpr, EP_OuterON) ) return 0; /* rule (5) */
}
if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON) /* (6a) */
&& (pSrcList->a[0].fg.jointype & JT_LTORJ)!=0 /* Fast pre-test of (6b) */
){
int jj;
for(jj=0; jj<iSrc; jj++){
if( pExpr->w.iJoin==pSrcList->a[jj].iCursor ){
if( (pSrcList->a[jj].fg.jointype & JT_LTORJ)!=0 ){
return 0; /* restriction (6) */
}
break;
}
}
}
return sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor); /* rules (1), (2) */
}