RE: Failed transaction statistics to measure the logical replication progress

On Wednesday, September 29, 2021 2:59 PM Greg Nancarrow <gregn4422(at)gmail(dot)com> wrote:
> On Tue, Sep 28, 2021 at 8:04 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)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.
Yeah, I agree with your conclusion.
I feel we cannot avoid changing some base of pg_stat_subscription
for the xact stats.

Best Regards,
Takamichi Osumi