From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: Jakub Wartak <jakub.wartak@enterprisedb.com>
Cc: Andrew Dunstan <andrew@dunslane.net>
Cc: Peter Eisentraut <peter@eisentraut.org>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Performance degradation on concurrent COPY into a single relation in PG16.
Date: Wed, 06 Sep 2023 18:01:53 -0400
Message-ID: <1578568.1694037713@sss.pgh.pa.us> (raw)
In-Reply-To: <20230816225432.fibahevlqsssj2hv@awork3.anarazel.de>
References: <20230812200504.li5vomg36j2tretx@awork3.anarazel.de>
<20230816111546.wrkepwwjwfuottpq@alvherre.pgsql>
<20230816225432.fibahevlqsssj2hv@awork3.anarazel.de>
Andres Freund <andres@anarazel.de> writes:
> On 2023-08-16 13:15:46 +0200, Alvaro Herrera wrote:
>> Since the wins from this patch were replicated and it has been pushed, I
>> understand that this open item can be marked as closed, so I've done
>> that.
> Thanks!
It turns out that this patch is what's making buildfarm member
chipmunk fail in contrib/pg_visibility [1]. That's easily reproduced
by running the test with shared_buffers = 10MB. I didn't dig further
than the "git bisect" result:
$ git bisect bad
82a4edabd272f70d044faec8cf7fd1eab92d9991 is the first bad commit
commit 82a4edabd272f70d044faec8cf7fd1eab92d9991
Author: Andres Freund <andres@anarazel.de>
Date: Mon Aug 14 09:54:03 2023 -0700
hio: Take number of prior relation extensions into account
but I imagine the problem is that the patch's more aggressive
relation-extension heuristic is causing the table to have more
pages than the test case expects. Is it really a good idea
for such a heuristic to depend on shared_buffers? If you don't
want to change the heuristic then we'll have to find a way to
tweak this test to avoid it.
regards, tom lane
[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=chipmunk&dt=2023-09-06%2014%3A14%3A51
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, andres@anarazel.de, hlinnaka@iki.fi, alvherre@alvh.no-ip.org, sawada.mshk@gmail.com, dgrowleyml@gmail.com, dean.a.rasheed@gmail.com, jakub.wartak@enterprisedb.com, andrew@dunslane.net, peter@eisentraut.org, pgsql-hackers@lists.postgresql.org
Subject: Re: Performance degradation on concurrent COPY into a single relation in PG16.
In-Reply-To: <1578568.1694037713@sss.pgh.pa.us>
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