Re: Support to define custom wait events for extensions

On Fri, Jun 16, 2023 at 11:14:05AM +0900, Masahiro Ikeda wrote:
> I tried to query on pg_stat_activity to check the background worker
> invoked by pg_prewarm. But, I found that pg_stat_activity doesn't show
> it although I may be missing something...
>
> So, I tried to implement TAP tests. But I have a problem with it.
> I couldn't find the way to check the status of another backend
> while the another backend wait with custom wait events.

Hmm.  Right.  It seems to me that BGWORKER_BACKEND_DATABASE_CONNECTION
is required in this case, with BackgroundWorkerInitializeConnection()
to connect to a database (or not, like the logical replication
launcher if only access to shared catalogs is wanted).

I have missed that the leader process of pg_prewarm does not use that,
because it has no need to connect to a database, but its workers do.
So it is not going to show up in pg_stat_activity.
--
Michael