From: David Rowley <drowley@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix UNION planner datatype issue
Date: Fri, 10 Jan 2025 01:31:48 +0000
Message-ID: <E1tW3sK-000kxN-Bl@gemulon.postgresql.org> (raw)
Fix UNION planner datatype issue
66c0185a3 gave the planner the ability to have union child queries
provide the union planner with pre-sorted input so that UNION queries
could be more efficiently implemented using Merge Append.
That commit overlooked checking that the UNION target list and the union
child target list's types all match. In some corner cases, this could
result in the planner producing sorts using the sort operator of the
top-level UNION's target list type rather than of the union child's
target list's type. The implications of this range from silently
working correctly, despite using the wrong sort operator all the way up
to a segmentation fault.
Here we fix by adjusting the planner so it makes no attempt to have the
subquery produce pre-sorted results when the data type of the UNION
target list and the types from the subquery target list don't match
exactly.
Backpatch to 17, where 66c0185a3 was introduced.
Reported-by: Jason Smith <dqetool@126.com>
Diagnosed-by: Tom Lane <tgl@sss.pgh.pa.us>
Bug: 18764
Discussion: https://postgr.es/m/18764-63ad667ea26e877a%40postgresql.org
Backpatch-through: 17
Branch
------
REL_17_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/5db9367e51136cb270feb79c741f68c1413dce78
Modified Files
--------------
src/backend/optimizer/plan/planner.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-committers@postgresql.org
Cc: drowley@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix UNION planner datatype issue
In-Reply-To: <E1tW3sK-000kxN-Bl@gemulon.postgresql.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox