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Suppress subquery pullup and pushdown when the subquery has any

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set-returning functions in its target list.  This ensures that we
won't rewrite the query in a way that places set-returning functions
into quals (WHERE clauses).  Cf. bug reports from Joe Conway.
This commit is contained in:
Tom Lane
2001-12-10 22:54:12 +00:00
parent 584f818bef
commit 63cc56de54
4 changed files with 59 additions and 6 deletions
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14
src/backend/optimizer/path/allpaths.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/allpaths.c,v 1.82 2001/11/05 17:46:25 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/allpaths.c,v 1.83 2001/12/10 22:54:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -305,7 +305,14 @@ set_subquery_pathlist(Query *root, RelOptInfo *rel,
* checking that seems more work than it's worth. In any case, a
* plain DISTINCT is safe to push down past.)
*
* 3. We do not push down clauses that contain subselects, mainly because
* 3. If the subquery has any ITER nodes (ie, functions returning sets)
* in its target list, we do not push down any quals, since the quals
* might refer to those tlist items, which would mean we'd introduce
* functions-returning-sets into the subquery's WHERE/HAVING quals.
* (It'd be sufficient to not push down quals that refer to those
* particular tlist items, but that's much clumsier to check.)
*
* 4. We do not push down clauses that contain subselects, mainly because
* I'm not sure it will work correctly (the subplan hasn't yet
* transformed sublinks to subselects).
*
@ -318,7 +325,8 @@ set_subquery_pathlist(Query *root, RelOptInfo *rel,
if (subquery->setOperations == NULL &&
subquery->limitOffset == NULL &&
subquery->limitCount == NULL &&
!has_distinct_on_clause(subquery))
!has_distinct_on_clause(subquery) &&
!contain_iter_clause((Node *) subquery->targetList))
{
/* OK to consider pushing down individual quals */
List *upperrestrictlist = NIL;