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In-Reply-To: <aRNmEPQ18qZlLowV@nathan>
From: Robert Treat <rob@xzilla.net>
Date: Tue, 11 Nov 2025 14:43:19 -0500
Message-ID: 
 <CABV9wwM_Q9+-AXga=t=RPXMYHRNoRK_UEqXy-Q8_=WcOjJ=iAw@mail.gmail.com>
Subject: Re: another autovacuum scheduling thread
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Sami Imseih <samimseih@gmail.com>,
	Robert Haas <robertmhaas@gmail.com>,
 Jeremy Schneider <schneider@ardentperf.com>,
	pgsql-hackers@postgresql.org
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On Tue, Nov 11, 2025 at 11:36=E2=80=AFAM Nathan Bossart
<nathandbossart@gmail.com> wrote:
>
> Still catching up on the latest discussion, but here's a v8 patch that
> amends the DEBUG3 in relation_needs_vacanalyze() to also log the score.  =
I
> might attempt to add some sort of brief documentation about autovacuum
> prioritization next.
>
> From skimming the latest discussion, I gather we might want to consider
> re-sorting the list periodically.  Is the idea that we'll re-sort the
> remaining tables in the list, or that we'll basically restart
> do_autovacuum()?  If it's the latter, then we'll need to come up with som=
e
> way to decide when to stop for the current database.  Right now, we just =
go
> through pg_class and call it a day.
>

FWIW, when I have built these types of systems in the past, and when I
wanted an aggressive recheck-type mechanism, the most common methods
involved tying it to autovacuum_max_workers. This usually was done
under the assumption that generating the list was relatively cheap and
that higher xid age would generate higher priority candidates. Of
course I also was biased towards having it be user controllable at the
database level (ie. no need to modify some control file or cron job or
whatever). To the degree those things are aligned here, there is at
least some anecdata that this is a usable setting.


Robert Treat
https://xzilla.net