Re: New statistics for tuning WAL buffer size

On Mon, Sep 28, 2020 at 8:24 AM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> At Mon, 28 Sep 2020 08:11:23 +0530, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote in
> > One other thing that occurred to me today is can't we keep this as
> > part of PgStat_GlobalStats? We can use pg_stat_reset_shared('wal'); to
> > reset it. It seems to me this is a cluster-wide stats and somewhat
> > similar to some of the other stats we maintain there.
>
> I like that direction, but PgStat_GlobalStats is actually
> PgStat_BgWriterStats and cleard by a RESET_BGWRITER message.
>

Yeah, I think if we want to pursue this direction then we probably
need to have a separate message to set/reset WAL-related stuff. I
guess we probably need to have a separate reset timestamp for WAL. I
think the difference would be that we can have one structure to refer
to global_stats instead of referring to multiple structures and we
don't need to issue separate read/write calls but OTOH I don't see
many disadvantages of the current approach as well.

--
With Regards,
Amit Kapila.