diff options
Diffstat (limited to 'src/backend/optimizer/path/allpaths.c')
| -rw-r--r-- | src/backend/optimizer/path/allpaths.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c index 12081c2cda5..42d8761845c 100644 --- a/src/backend/optimizer/path/allpaths.c +++ b/src/backend/optimizer/path/allpaths.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.123 2004/12/31 22:00:00 pgsql Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.124 2005/03/10 23:21:21 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -334,13 +334,10 @@ set_subquery_pathlist(Query *root, RelOptInfo *rel, /* * If there are any restriction clauses that have been attached to the - * subquery relation, consider pushing them down to become HAVING - * quals of the subquery itself. (Not WHERE clauses, since they may - * refer to subquery outputs that are aggregate results. But - * planner.c will transfer them into the subquery's WHERE if they do - * not.) This transformation is useful because it may allow us to - * generate a better plan for the subquery than evaluating all the - * subquery output rows and then filtering them. + * subquery relation, consider pushing them down to become WHERE or + * HAVING quals of the subquery itself. This transformation is useful + * because it may allow us to generate a better plan for the subquery + * than evaluating all the subquery output rows and then filtering them. * * There are several cases where we cannot push down clauses. * Restrictions involving the subquery are checked by @@ -795,8 +792,17 @@ subquery_push_qual(Query *subquery, List *rtable, Index rti, Node *qual) qual = ResolveNew(qual, rti, 0, rtable, subquery->targetList, CMD_SELECT, 0); - subquery->havingQual = make_and_qual(subquery->havingQual, - qual); + + /* + * Now attach the qual to the proper place: normally WHERE, but + * if the subquery uses grouping or aggregation, put it in HAVING + * (since the qual really refers to the group-result rows). + */ + if (subquery->hasAggs || subquery->groupClause || subquery->havingQual) + subquery->havingQual = make_and_qual(subquery->havingQual, qual); + else + subquery->jointree->quals = + make_and_qual(subquery->jointree->quals, qual); /* * We need not change the subquery's hasAggs or hasSublinks flags, |