Re: Can a child process detect postmaster death when in pg_usleep?

On Tue, Apr 20, 2021 at 07:36:39AM +0530, Bharath Rupireddy wrote:
> I'm attaching 3 patches that replace pg_usleep with WaitLatch: 0001 in
> lazy_truncate_heap, 0002 in do_pg_stop_backup and 0003 for Pre and
> Post Auth Delay. Regression tests pass with these patches. Please
> review them.

+       if (backup_started_in_recovery)
+           latch = &XLogCtl->recoveryWakeupLatch;
+       else
+           latch = MyLatch;
recoveryWakeupLatch is used by the startup process, but it has nothing
to do with do_pg_stop_backup().  Why are you doing that?

I can get behind the change for the truncation lock when finishing a
VACUUM as that helps with monitoring.  Now, I am not sure I get the
point of changing anything for {post,pre}_auth_delay that are
developer options.  Please note that at this stage we don't know the
backend activity in pg_stat_activity, so the use of wait events is not
really interesting.  On top of that, not reacting on signals can be
interesting to keep as a behavior for developers?
--
Michael