Date: Sun, 6 Mar 2022 15:04:02 +0100
From: hubert depesz lubaczewski <depesz@depesz.com>
Sender: depesz@depesz.com
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL General <pgsql-general@lists.postgresql.org>,
	Andres Freund <andres@anarazel.de>
Subject: Re: Interesting fail when migrating Pg from Ubuntu Bionic to Focal
Message-ID: <20220306140402.GA6360@depesz.com>
Reply-To: depesz@depesz.com
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On Fri, Mar 04, 2022 at 05:03:14PM -0500, Tom Lane wrote:
> hubert depesz lubaczewski <depesz@depesz.com> writes:
> > On Fri, Mar 04, 2022 at 02:09:52PM -0500, Tom Lane wrote:
> >> I tried and failed to reproduce this on Fedora 35 on aarch64,
> >> but that has what I think is a newer LLVM version:
> 
> > I have suspicion that it also kinda depends on number of rows in there.
> > When I deleted some schemas, which included some functions, the problem
> > disappeared.
> > I wasn't able to pinpoint specific thing, though, and when I called the
> > pg_proc + pg_roles query for each separate row - it worked flawlessly.
> 
> Mmm ... it might have just been that the planner chose not to use
> JIT when it thought there were fewer rows involved.  Did you check
> with EXPLAIN that these cut-down cases still used JIT?

Hi,
I tore these boxes down, so can't check immediately, but I think
I remember that you're right - single-row queries didn't use JIT.

Best regards,

depesz