Re: Skipping logical replication transactions on subscriber side

On Tue, Nov 16, 2021 at 5:31 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> Right. I've fixed this issue and attached an updated patch.
>

A couple of comments for the v23 patch:

doc/src/sgml/monitoring.sgml
(1) inconsistent decription
I think that the following description seems inconsistent with the
previous description given above it in the patch (i.e. "One row per
subscription worker, showing statistics about errors that occurred on
that subscription worker"):

"The <structname>pg_stat_subscription_workers</structname> view will
contain one row per subscription error reported by workers applying
logical replication changes and workers handling the initial data copy
of the subscribed tables."

I think it is inconsistent because it implies there could be multiple
subscription error rows for the same worker.
Maybe the following wording could be used instead, or something similar:

"The <structname>pg_stat_subscription_workers</structname> view will
contain one row per subscription worker on which errors have occurred,
for workers applying logical replication changes and workers handling
the initial data copy of the subscribed tables."

(2) null vs NULL
The "subrelid" column description uses "null" but the "command" column
description uses "NULL".
I think "NULL" should be used for consistency.

Regards,
Greg Nancarrow
Fujitsu Australia