Hi,
commit a31ad27fc5d introduced required_relids field. By default, it
links to the clause_relids.
It works good while we do not modify clause_relids or required_relids.
But in the case of modification such initialization demands us to
remember, that this field is shared. And we need to do bms_copy() before
making any changes (see [1] for example).
Also, we make some changes of the RestrictInfo fields (see patch [2])
during removing of unneeded self joins.
I propose to do more secure initialization way of required_relids (see
patch in attachment).
[1] commit 4e97631e6a9, analyzejoins.c, line 434,435:
rinfo->required_relids = bms_copy(rinfo->required_relids);
rinfo->required_relids = bms_del_member(rinfo->required_relids, relid);
[2] https://commitfest.postgresql.org/23/1712/
--
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company
>From 1dc021c0c9827ecd530ee3bb0020bad9bc5d14b6 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepik...@postgrespro.ru>
Date: Mon, 15 Jul 2019 11:07:20 +0500
Subject: [PATCH] More secure initialization of required_relids field
---
src/backend/optimizer/util/restrictinfo.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c
index 3b50fd29ad..450558e61b 100644
--- a/src/backend/optimizer/util/restrictinfo.c
+++ b/src/backend/optimizer/util/restrictinfo.c
@@ -172,7 +172,7 @@ make_restrictinfo_internal(Expr *clause,
if (required_relids != NULL)
restrictinfo->required_relids = required_relids;
else
- restrictinfo->required_relids = restrictinfo->clause_relids;
+ restrictinfo->required_relids = bms_copy(restrictinfo->clause_relids);
/*
* Fill in all the cacheable fields with "not yet set" markers. None of
--
2.17.1
