From: Tom Lane <tgl@sss.pgh.pa.us>
To: depesz@depesz.com
cc: 1986comatose@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19014: Automatic aggressive VACUUM on template0 and
 template1 pg_shdepend runs every minute
In-reply-to: <aJSqb0zUoKZ05w8V@depesz.com>
References: <19014-3b29e6cbcb5f0b82@postgresql.org>
 <aJSqb0zUoKZ05w8V@depesz.com>
Comments: In-reply-to hubert depesz lubaczewski <depesz@depesz.com>
	message dated "Thu, 07 Aug 2025 15:30:23 +0200"
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Date: Thu, 07 Aug 2025 17:33:34 -0400
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hubert depesz lubaczewski <depesz@depesz.com> writes:
> On Thu, Aug 07, 2025 at 07:47:58AM +0000, PG Bug reporting form wrote:
>> We only actively use the ecount database, yet our logs show that an
>> automatic =E2=80=9Caggressive=E2=80=9D VACUUM is repeatedly running on
>> template0.pg_catalog.pg_shdepend and template1.pg_catalog.pg_shdepend a=
t
>> roughly one-minute intervals. Since the template databases aren=E2=80=99=
t used for
>> normal operations, these vacuums seem unnecessary and are consuming sys=
tem
>> resources. We believe this behavior is a bug.

> I bet you have some long transaction somewhere, and this table is shared
> (same table visible in all databases).

Another theory, again remembering this is a shared catalog, is that
there is enough update traffic on pg_shdepend to justify constant
vacuuming.  That could be plausible if there's a lot of object
creation and deletion going on (even just temporary tables, I think).

Anyway, I don't see any such behavior here after setting
log_autovacuum_min_duration =3D 0.  We're going to need more
information to reproduce the problem.

			regards, tom lane