From: Tom Lane <tgl@sss.pgh.pa.us>
To: depesz@depesz.com
Cc: pgsql-bugs mailing list <pgsql-bugs@postgresql.org>
Cc: David Rowley <dgrowleyml@gmail.com>
Subject: Re: UNION removes almost all rows (not duplicates) - in fresh build of pg17!
Date: Mon, 20 May 2024 13:11:24 -0400
Message-ID: <3538123.1716225084@sss.pgh.pa.us> (raw)
In-Reply-To: <Zktzf926vslR35Fv@depesz.com>
References: <Zktzf926vslR35Fv@depesz.com>
hubert depesz lubaczewski <depesz@depesz.com> writes:
> $ select count(*) from ( select * from pg_class where relkind = 'r' union select * from pg_class where relkind = 'i' );
> count
> ───────
> 1
> (1 row)
Ugh, that is awful. Bisecting shows it broke at
commit 66c0185a3d14bbbf51d0fc9d267093ffec735231
Author: David Rowley <drowley@postgresql.org>
Date: Mon Mar 25 14:31:14 2024 +1300
Allow planner to use Merge Append to efficiently implement UNION
I've not looked at the patch, but somehow it's totally forgetting
what it's supposed to be unique-ifying on.
regards, tom lane
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To: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, depesz@depesz.com, dgrowleyml@gmail.com
Subject: Re: UNION removes almost all rows (not duplicates) - in fresh build of pg17!
In-Reply-To: <3538123.1716225084@sss.pgh.pa.us>
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