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

hubert depesz lubaczewski <depesz(at)depesz(dot)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