From 3ef18797b83b9b274218009802a5994b7f41c818 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 24 Oct 2007 20:54:27 +0000 Subject: [PATCH] Fix an error in make_outerjoininfo introduced by my patch of 30-Aug: the code neglected to test whether an outer join's join-condition actually refers to the lower outer join it is looking at. (The comment correctly described what was supposed to happen, but the code didn't do it...) This often resulted in adding an unnecessary constraint on the join order of the two outer joins, which was bad enough. However, it also seems to expose a performance problem in an older patch (from 15-Feb): once we've decided that there is a join ordering constraint, we will start trying clauseless joins between every combination of rels within the constraint, which pointlessly eats up lots of time and space if there are numerous rels below the outer join. That probably needs to be revisited :-(. Per gripe from Jakub Ouhrabka. --- src/backend/optimizer/plan/initsplan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index 70543613fe..bacd875abf 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.134 2007/10/04 20:44:47 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.135 2007/10/24 20:54:27 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -623,6 +623,7 @@ make_outerjoininfo(PlannerInfo *root, * rel in the lower OJ's min_righthand, not its whole syn_righthand. */ if (bms_overlap(left_rels, otherinfo->syn_righthand) && + bms_overlap(clause_relids, otherinfo->syn_righthand) && !bms_overlap(strict_relids, otherinfo->min_righthand)) { min_lefthand = bms_add_members(min_lefthand, -- 2.40.0