On Mon, Apr 12, 2021 at 02:56:59PM +0800, Julien Rouhaud wrote:
> I think we should simply document that %Q is not compatible with
> log_statements.
Hearing no objection I documented that limitation.
>
> > While making the feature run on some test server, I have noticed that
> > %Q would log some garbage query ID for autovacuum workers that's kept
> > around. That looks wrong.
>
> I've not been able to reproduce it, do you have some hint on how to do it?
>
> Maybe setting a zero queryid at the beginning of AutoVacWorkerMain() could fix
> the problem?
It turns out that the problem was simply that some process can inherit a
PgBackendStatus for which a previous backend reported a queryid. For processes
like autovacuum process, they will never report a new identifier so they
reported the previous one. Resetting the field like the other ones in
pgstat_bestart() fixes the problem for autovacuum and any similar process.
