Re: Design of pg_stat_subscription_workers vs pgstats

On Sat, Feb 19, 2022 at 10:35 PM David G. Johnston
<david(dot)g(dot)johnston(at)gmail(dot)com> wrote:
>
> On Sat, Feb 19, 2022 at 9:37 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
>>
>> IMO the type of information you'd want for apply failures is substantially
>>
>> different enough from worker failures that I don't really see the temptation
>> to put them in the same table.
>>
>
> It's an error message and a transaction LSN in both cases right now, along with knowledge of whether said transaction only affects a single table (relid is not null) or not (relid is null). Do you have a concrete idea in mind that would make this separation need more obvious?
>

I would also like to mention that in some cases, sync workers also
behaves like apply worker (after initial sync till it catches up with
the apply worker) and try to stream and apply changes similar to apply
worker. The error during that phase will be no different than the
apply worker. One idea to make the separation more obvious is to
introduce 'worker_type' column similar to backend_type in
pg_stat_activity which will tell whether it is an apply worker or a
table sync worker.

--
With Regards,
Amit Kapila.