From: Tom Lane <tgl@sss.pgh.pa.us>
To: liam saffioti <liam.saffiotti@gmail.com>
cc: Avinash Vallarapu <avinash.vallarapu@gmail.com>,
        pgsql-admin <pgsql-admin@lists.postgresql.org>
Subject: Re: autoovacuum launcher process
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Comments: In-reply-to liam saffioti <liam.saffiotti@gmail.com>
	message dated "Mon, 13 Sep 2021 16:30:16 +0300"
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Date: Mon, 13 Sep 2021 09:46:14 -0400
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liam saffioti <liam.saffiotti@gmail.com> writes:
> Do you think timescaledb is causing this problem?

Seems possible.

> 2021-09-10 01:00:32.691     156668  FATAL:  cannot read pg_class without
> having selected a database
> 2021-09-10 01:00:33.356     110257  LOG:  autovacuum launcher process (PID
> 156668) exited with exit code 1

This is pretty clear evidence that some code running inside the
autovacuum launcher process tried to read a non-shared catalog, which it
cannot do because the launcher isn't connected to any specific database
within the cluster.  It is highly unlikely that anything in core Postgres
is doing that; we'd have noticed.  So I conclude that some extension code
is carelessly trying to do catalog accesses without checking to see if
it's running in a background process that doesn't support that.

Of the extensions you listed, timescaledb is perhaps the most likely to
contain such a bug; but I don't know much about hypopg, pg_partman,
pg_stat_kcache, or powa, so I can't completely rule those out.  It would
have to be an extension that sometimes acts of its own accord without
being called by a SQL command, so the list of suspects isn't all that
long.

Anyway, your first step should be to make sure you have up-to-date
versions of all those extensions.  If you do, then try filing a bug
with timescaledb.

			regards, tom lane