Re: Collect statistics about conflicts in logical replication

On Mon, Sep 2, 2024 at 1:28 PM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> On Mon, Sep 2, 2024 at 4:20 AM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> >
> > On Fri, Aug 30, 2024 at 4:24 PM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
> > >
> > > On Fri, Aug 30, 2024 at 10:53 AM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> > > >
> > ...
> > > > 2. Arrange all the counts into an intuitive/natural order
> > > >
> > > > There is an intuitive/natural ordering for these counts. For example,
> > > > the 'confl_*' count fields are in the order insert -> update ->
> > > > delete, which LGTM.
> > > >
> > > > Meanwhile, the 'apply_error_count' and the 'sync_error_count' are not
> > > > in a good order.
> > > >
> > > > IMO it makes more sense if everything is ordered as:
> > > > 'sync_error_count', then 'apply_error_count', then all the 'confl_*'
> > > > counts.
> > > >
> > > > This comment applies to lots of places, e.g.:
> > > > - docs (doc/src/sgml/monitoring.sgml)
> > > > - function pg_stat_get_subscription_stats (pg_proc.dat)
> > > > - view pg_stat_subscription_stats (src/backend/catalog/system_views.sql)
> > > > - TAP test SELECTs (test/subscription/t/026_stats.pl)
> > > >
> > > > As all those places are already impacted by this patch, I think it
> > > > would be good if (in passing) we (if possible) also swapped the
> > > > sync/apply counts so everything is ordered intuitively top-to-bottom
> > > > or left-to-right.
> > >
> > > Not sure about this though. It does not seem to belong to the current patch.
> > >
> >
> > Fair enough. But, besides being inappropriate to include in the
> > current patch, do you think the suggestion to reorder them made sense?
> > If it has some merit, then I will propose it again as a separate
> > thread.
> >
>
> Yes, I think it makes sense. With respect to internal code, it might
> be still okay as is, but when it comes to pg_stat_subscription_stats,
> I think it is better if user finds it in below order:
> subid | subname | sync_error_count | apply_error_count | confl_*
>
> rather than the existing one:
> subid | subname | apply_error_count | sync_error_count | confl_*
>

Hi Shveta, Thanks. FYI - I created a new thread for this here [1].

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[1] https://www.postgresql.org/message-id/CAHut+PvbOw90wgGF4aV1HyYtX=6pjWc+pn8_fep7L=aLXwXkqg@mail.gmail.com

Kind Regards,
Peter Smith.
Fujitsu Australia