Re: [PATCH] pg_stat_activity: make slow/hanging authentication more visible

On Tue, Mar 4, 2025 at 8:45 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> What this is telling us is that we should change the query scanning
> pg_stat_activity for a PID of a backend in 'starting' state so as we
> also check the wait_event init-pre-auth, as this is reported when
> using injection point waits. The attached should be enough to take
> care of this race condition.

That's a lot easier than the rabbit hole I was running down; thank you.

> - "SELECT pid FROM pg_stat_activity WHERE state = 'starting';");
> + qq{SELECT pid FROM pg_stat_activity
> + WHERE state = 'starting' and wait_event = 'init-pre-auth';});

I had intended for this part of the patch to also wait for client
backends only (see v8-0001, 001_ssltests.pl), but I must have
misapplied it. (The ssltests change was lost completely when that file
was dropped from the set.) So while we're at it, should we add a
`backend_type = 'client backend'` filter to stop that from flaking in
the future? That would further align this query with the
wait_for_event() implementation.

Thanks,
--Jacob