Re: BUG #19014: Automatic aggressive VACUUM on template0 and template1 pg_shdepend runs every minute

양주희 <1986comatose@gmail.com>

From: 양주희 <1986comatose@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: depesz@depesz.com, pgsql-bugs@lists.postgresql.org
Date: 2025-08-11T09:09:09Z
Lists: pgsql-bugs
Hello, Thank you for your help. I ran the query you suggested: select now()
- xact_start from pg_stat_activity order by xact_start asc nulls last limit
1 The result was 00:00:00.96726, which suggests there are no long-running
transactions. Regarding Tom Lane's suggestion, our application does
frequently create temporary tables. This might be a factor contributing to
the constant vacuuming of pg_shdepend. I am ready to provide more
information if you need it to help reproduce the issue. Thank you


2025년 8월 8일 (금) 오전 6:33, Tom Lane <tgl@sss.pgh.pa.us>님이 작성:

> 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 “aggressive” VACUUM is repeatedly running on
> >> template0.pg_catalog.pg_shdepend and template1.pg_catalog.pg_shdepend at
> >> roughly one-minute intervals. Since the template databases aren’t used
> for
> >> normal operations, these vacuums seem unnecessary and are consuming
> system
> >> 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 = 0.  We're going to need more
> information to reproduce the problem.
>
>                         regards, tom lane
>