On 2023-06-16 16:46, Michael Paquier wrote:
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.
Yes. Thanks to your advice, I understood that
BGWORKER_BACKEND_DATABASE_CONNECTION is the reason.
I could make the TAP test that invokes a background worker waiting
forever
and checks its custom wait event in pg_stat_activity. So, I'll make
patches
including test codes next week.
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
