From fdd48b185288e3e77827d4d81dd1561e17bde90c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 7 May 2009 20:13:09 +0000
Subject: [PATCH] Ooops ... make_outerjoininfo wasn't actually enforcing the
join order restrictions specified for semijoins in optimizer/README, to wit
that you can't reassociate outer joins into or out of the RHS of a semijoin.
Per report from Heikki.
---
src/backend/optimizer/plan/initsplan.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index b31ffa81cc1..56100ba6cc8 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 1.152 2009/05/06 20:31:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.153 2009/05/07 20:13:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -654,7 +654,8 @@ make_outerjoininfo(PlannerInfo *root,
* lower join's RHS and the lower OJ's join condition is strict, we
* can interchange the ordering of the two OJs; otherwise we must add
* lower OJ's full syntactic relset to min_righthand. Here, we must
- * preserve ordering anyway if the lower OJ is an antijoin.
+ * preserve ordering anyway if either the current join is a semijoin,
+ * or the lower OJ is an antijoin.
*
* Here, we have to consider that "our join condition" includes any
* clauses that syntactically appeared above the lower OJ and below
@@ -670,6 +671,7 @@ make_outerjoininfo(PlannerInfo *root,
if (bms_overlap(right_rels, otherinfo->syn_righthand))
{
if (bms_overlap(clause_relids, otherinfo->syn_righthand) ||
+ jointype == JOIN_SEMI ||
otherinfo->jointype == JOIN_ANTI ||
!otherinfo->lhs_strict || otherinfo->delay_upper_joins)
{
--
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