From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
cc: Andres Freund <andres@anarazel.de>, Peter Geoghegan <pg@bowt.ie>,
        David Rowley <dgrowleyml@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Intermittent buildfarm failures on wrasse
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Comments: In-reply-to Noah Misch <noah@leadboat.com>
	message dated "Wed, 13 Apr 2022 19:51:22 -0700"
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Date: Thu, 14 Apr 2022 12:01:23 -0400
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Noah Misch <noah@leadboat.com> writes:
> On Wed, Apr 13, 2022 at 06:51:12PM -0700, Andres Freund wrote:
>> Noah, any chance you could enable log_autovacuum_min_duration=3D0 on
>> wrasse?

> Done.  Also forced hourly builds.

Thanks!  We now have two failing runs with the additional info [1][2],
and in both, it's clear that the first autovac worker doesn't launch
until 1 minute after postmaster start, by which time we're long done
with the test scripts of interest.  So whatever is breaking this is
not an autovac worker.

I think I'm going to temporarily add a couple of queries to check
what tenk1's relallvisible actually is, just so we can confirm
positively that that's what's causing the plan change.  (I'm also
curious about whether the CREATE INDEX steps manage to change it
at all.)

			regards, tom lane

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dwrasse&dt=3D=
2022-04-14%2013%3A28%3A14
[2] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dwrasse&dt=3D=
2022-04-14%2004%3A48%3A13