Re: JumbleQuery ma treat different GROUP BY expr as the same - Mailing list pgsql-hackers

On Tue, Jan 13, 2026 at 3:10 PM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Mon, Jan 12, 2026 at 04:20:44PM +0800, jian he wrote:
> > While working on it, I guess I found another bug,  below JumbleQuery will return
> > the same result:
> >
> > SELECT FROM (VALUES (1::INT, 2::INT)) AS t(a, b) ORDER BY a, b;
> > SELECT a FROM (VALUES (1::INT, 2::INT)) AS t(a, b) ORDER BY a, b;
> > SELECT a, b FROM (VALUES (1::INT, 2::INT)) AS t(a, b) ORDER BY a, b;
> >
> > so I think TargetEntry.resjunk should not be marked as query_jumble_ignore.
>
> Not sure how to feel about this one, as a primary node.  3db72ebcbe20
> has put a query_jumble_ignore to TargetEntry.resjunk which was simply
> a consistent move with the pre-v15 branches because these columns have
> always been ignored.  I have never heard complaints about that in the
> field with PGSS, TBH.  The original choice comes from this thread,
> back in 2012 when this was still integrated into PGSS:
> https://www.postgresql.org/message-id/CAEYLb_WGeFCT7MfJ8FXf-CR6BSE6Lbn%2BO1VX3%2BOGrc4Bscn4%3DA%40mail.gmail.com
>

if not remove the query_jumble_ignore from TargetEntry.resjunk
the below query would have the same QueryID.

SELECT COUNT(*), a FROM (VALUES (1::INT, 2::INT)) AS t(a, b) GROUP BY a, b;
SELECT COUNT(*), a, b FROM (VALUES (1::INT, 2::INT)) AS t(a, b) GROUP BY a, b;

It affects queries that include an ORDER BY or GROUP BY clause, so a patch is
attached.



--
jian
https://www.enterprisedb.com/