From: David Rowley <drowley@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix possible usage of incorrect UPPERREL_SETOP RelOptInfo
Date: Tue, 04 Nov 2025 22:48:31 +0000
Message-ID: <E1vGPpH-0053iF-0S@gemulon.postgresql.org> (raw)
Fix possible usage of incorrect UPPERREL_SETOP RelOptInfo
03d40e4b5 allowed dummy UNION [ALL] children to be removed from the plan
by checking for is_dummy_rel(). That commit neglected to still account
for the relids from the dummy rel so that the correct UPPERREL_SETOP
RelOptInfo could be found and used for adding the Paths to.
Not doing this could result in processing of subsequent UNIONs using the
same RelOptInfo as a previously processed UNION, which could result in
add_path() freeing old Paths that are needed by the previous UNION.
The same fix was independently submitted (2 mins later) by Richard Guo.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Author: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/bee34aec-659c-46f1-9ab7-7bbae0b7616c@gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/fdda78e361f136ec2b8de579b366c1e66bba1199
Modified Files
--------------
src/backend/optimizer/prep/prepunion.c | 8 ++++++--
src/test/regress/expected/union.out | 6 +++---
2 files changed, 9 insertions(+), 5 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: drowley@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix possible usage of incorrect UPPERREL_SETOP RelOptInfo
In-Reply-To: <E1vGPpH-0053iF-0S@gemulon.postgresql.org>
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