From 953208a34cbb7585ed4ae782141052461d35739b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 6 Dec 2005 16:50:36 +0000
Subject: [PATCH] In a nestloop inner indexscan, it's OK to use pushed-down
baserestrictinfo clauses even if it's an outer join. This is a corner case
since such clauses could only arise from weird OUTER JOIN ON conditions, but
worth fixing. Per example from Ron at cheapcomplexdevices.com.
---
src/backend/optimizer/path/indxpath.c | 34 ++++++++++-----------------
1 file changed, 12 insertions(+), 22 deletions(-)
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index c74e530e2b7..159960764fb 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.195 2005/11/30 17:10:19 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.196 2005/12/06 16:50:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1357,27 +1357,9 @@ find_clauses_for_join(PlannerInfo *root, RelOptInfo *rel,
Relids outer_relids, bool isouterjoin)
{
List *clause_list = NIL;
- bool jfound = false;
Relids join_relids;
ListCell *l;
- /*
- * We can always use plain restriction clauses for the rel. We scan these
- * first because we want them first in the clause list for the convenience
- * of remove_redundant_join_clauses, which can never remove non-join
- * clauses and hence won't be able to get rid of a non-join clause if it
- * appears after a join clause it is redundant with.
- */
- foreach(l, rel->baserestrictinfo)
- {
- RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
-
- /* Can't use pushed-down clauses in outer join */
- if (isouterjoin && rinfo->is_pushed_down)
- continue;
- clause_list = lappend(clause_list, rinfo);
- }
-
/* Look for joinclauses that are usable with given outer_relids */
join_relids = bms_union(rel->relids, outer_relids);
@@ -1385,22 +1367,30 @@ find_clauses_for_join(PlannerInfo *root, RelOptInfo *rel,
{
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
- /* Can't use pushed-down clauses in outer join */
+ /* Can't use pushed-down join clauses in outer join */
if (isouterjoin && rinfo->is_pushed_down)
continue;
if (!bms_is_subset(rinfo->required_relids, join_relids))
continue;
clause_list = lappend(clause_list, rinfo);
- jfound = true;
}
bms_free(join_relids);
/* if no join clause was matched then forget it, per comments above */
- if (!jfound)
+ if (clause_list == NIL)
return NIL;
+ /*
+ * We can also use any plain restriction clauses for the rel. We put
+ * these at the front of the clause list for the convenience of
+ * remove_redundant_join_clauses, which can never remove non-join clauses
+ * and hence won't be able to get rid of a non-join clause if it appears
+ * after a join clause it is redundant with.
+ */
+ clause_list = list_concat(list_copy(rel->baserestrictinfo), clause_list);
+
/*
* We may now have clauses that are known redundant. Get rid of 'em.
*/
--
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