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From: Greg Nancarrow <gregn4422@gmail.com>
Date: Wed, 29 Sep 2021 15:59:20 +1000
Message-ID: 
 <CAJcOf-d9RON4XHKhTAsNWiR5_YCkhAZL3zui4gNQbDjiOCttYQ@mail.gmail.com>
Subject: Re: Failed transaction statistics to measure the logical replication
 progress
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>,
	"osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>,
	"pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
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On Tue, Sep 28, 2021 at 8:04 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> > Another idea could be to have a separate
> > view, say pg_stat_subscription_xact but I'm not sure it's a better
> > idea.
> >
>
> Yeah, that is another idea but I am afraid that having three different
> views for subscription stats will be too much. I think it would be
> better if we can display these additional stats via the existing view
> pg_stat_subscription or the new view pg_stat_subscription_errors (or
> whatever name we want to give it).
>


It seems that we have come full-circle in the discussion of how these
new stats could be best added.
Other than adding a new "pg_stats_subscription_xact" view (which Amit
thought would result in too many views) I don't see any clear solution
here, because the new xact-related cumulative stats don't really
consistently integrate with the existing in-memory stats in
pg_stat_subscription, and IMHO the new stats wouldn't integrate well
into the existing error-related stats in the
"pg_stat_subscription_errors" view (even if its name was changed, that
view in any case maintains lowel-level error details and the way error
entries are removed doesn't allow the "success" stats to be maintained
for the subscription and doesn't fit well with the added
"pg_stat_reset_subscription_error" function either).
If we can't really add another view like "pg_stats_subscription_xact",
it seems we need to find some way the new stats fit more consistently
into the existing "pg_stat_subscription" view.

Regards,
Greg Nancarrow
Fujitsu Australia