Horton

Re: Replication slot stats misgivings

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Date: 2021-04-12T11:08:34Z
Lists: pgsql-hackers 
On Mon, Apr 12, 2021 at 4:34 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Mon, Apr 12, 2021 at 6:19 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Mon, Apr 12, 2021 at 10:27 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > >
> > > On Sat, Apr 10, 2021 at 9:53 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > >
> > > >
> > > > It seems Vignesh has changed patches based on the latest set of
> > > > comments so you might want to rebase.
> > >
> > > I've merged my patch into the v6 patch set Vignesh submitted.
> > >
> > > I've attached the updated version of the patches. I didn't change
> > > anything in the patch that changes char[NAMEDATALEN] to NameData (0001
> > > patch) and patches that add tests.
> > >
> >
> > I think we can push 0001. What do you think?
>
> +1
>
> >
> > > In 0003 patch I reordered the
> > > output parameters of pg_stat_replication_slots; showing total number
> > > of transactions and total bytes followed by statistics for spilled and
> > > streamed transactions seems appropriate to me.
> > >
> >
> > I am not sure about this because I think we might want to add some
> > info of stream/spill bytes in total_bytes description (something like
> > stream/spill bytes are not in addition to total_bytes).
>
> Okay.
>
> > So probably
> > keeping these new counters at the end makes more sense to me.
>
> But I think all of those counters are new for users since
> pg_stat_replication_slots view will be introduced to PG14, no?
>

Right, I was referring to total_txns and total_bytes attributes. I
think keeping them at end after spill and stream counters should be
okay.

-- 
With Regards,
Amit Kapila.

Commits

  1. Doc: Update logical decoding stats information.

  2. Fix tests for replication slots stats.

  3. Update replication statistics after every stream/spill.

  4. Fix the computation of slot stats for 'total_bytes'.

  5. Another try to fix the test case added by commit f5fc2f5b23.

  6. Use HTAB for replication slot statistics.

  7. Fix test case added by commit f5fc2f5b23.

  8. Add information of total data processed to replication slot stats.

  9. Use NameData datatype for slotname in stats.