From 4ec15077b2eaa1f7713e4fff87e220a23c772688 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 28 Sep 2010 12:08:56 -0400 Subject: Fix PlaceHolderVar mechanism's interaction with outer joins. The point of a PlaceHolderVar is to allow a non-strict expression to be evaluated below an outer join, after which its value bubbles up like a Var and can be forced to NULL when the outer join's semantics require that. However, there was a serious design oversight in that, namely that we didn't ensure that there was actually a correct place in the plan tree to evaluate the placeholder :-(. It may be necessary to delay evaluation of an outer join to ensure that a placeholder that should be evaluated below the join can be evaluated there. Per recent bug report from Kirill Simonov. Back-patch to 8.4 where the PlaceHolderVar mechanism was introduced. --- src/backend/optimizer/plan/analyzejoins.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'src/backend/optimizer/plan/analyzejoins.c') diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 1355c18317a..5bcb15fea67 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -396,6 +396,8 @@ remove_rel_from_query(PlannerInfo *root, int relid, Relids joinrelids) phinfo->ph_eval_at = bms_add_member(phinfo->ph_eval_at, relid); phinfo->ph_needed = bms_del_member(phinfo->ph_needed, relid); + /* ph_may_need probably isn't used after this, but fix it anyway */ + phinfo->ph_may_need = bms_del_member(phinfo->ph_may_need, relid); } /* -- cgit v1.2.3