Re: Resetting spilled txn statistics in pg_stat_replication

On Tue, Jun 23, 2020 at 6:39 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Tue, Jun 23, 2020 at 3:48 PM Tomas Vondra
> <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> >
> > On Tue, Jun 23, 2020 at 10:58:18AM +0530, Amit Kapila wrote:
> > >On Tue, Jun 23, 2020 at 9:32 AM Masahiko Sawada
> > ><masahiko(dot)sawada(at)2ndquadrant(dot)com> wrote:
> > >>
> > >> On Sun, 21 Jun 2020 at 06:57, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> > >> >
> > >> > >
> > >> > >What if the decoding has been performed by multiple backends using the
> > >> > >same slot? In that case, it will be difficult to make the judgment
> > >> > >for the value of logical_decoding_work_mem based on stats. It would
> > >> > >make sense if we provide a way to set logical_decoding_work_mem for a
> > >> > >slot but not sure if that is better than what we have now.
> > >> > >
> > >>
> > >> I thought that the stats are relevant to what
> > >> logical_decoding_work_mem value was but not with who performed logical
> > >> decoding. So even if multiple backends perform logical decoding using
> > >> the same slot, the user can directly use stats as long as
> > >> logical_decoding_work_mem value doesn’t change.
> > >>

Today, I thought about it again, and if we consider the point that
logical_decoding_work_mem value doesn’t change much then having the
stats at slot-level would also allow computing
logical_decoding_work_mem based on stats. Do you think it is a
reasonable assumption that users won't change
logical_decoding_work_mem for different processes (WALSender, etc.)?

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com