Horton

Re: Replication slot stats misgivings

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>, Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Date: 2021-04-28T04:14:59Z
Lists: pgsql-hackers 
On Wed, Apr 28, 2021 at 9:37 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Wed, Apr 28, 2021 at 12:29 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Tue, Apr 27, 2021 at 11:02 AM vignesh C <vignesh21@gmail.com> wrote:
> > >
> > > On Tue, Apr 27, 2021 at 9:48 AM vignesh C <vignesh21@gmail.com> wrote:
> > > >
> > >
> > > Attached patch has the changes to update statistics during
> > > spill/stream which prevents the statistics from being lost during
> > > interrupt.
> > >
> >
> >  void
> > -UpdateDecodingStats(LogicalDecodingContext *ctx)
> > +UpdateDecodingStats(ReorderBuffer *rb)
> >
> > I don't think you need to change this interface because
> > reorderbuffer->private_data points to LogicalDecodingContext. See
> > StartupDecodingContext.
>
> +1
>
> With this approach, we could still miss the totalTxns and totalBytes
> updates if the decoding a large but less than
> logical_decoding_work_mem is interrupted, right?

Yes you are right, I felt that is reasonable and that way it reduces
frequent calls to the stats collector to update the stats.

Regards,
Vignesh

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.