Re: Add wait event for log emission? - Mailing list pgsql-hackers

On Tue, Jun 13, 2023 at 6:59 PM Andres Freund <andres@anarazel.de> wrote:
>
> Hi,
>
> I just helped somebody debug a postgres performance problem that turned out to
> be not actually be postgres' fault.  It turned out to be because postgres'
> stdout/stderr were piped to a program, and that program was slow. Whenever the
> pipe buffer filled up, postgres stopped making progress.
>
> That's not postgres' fault. But we make it too hard to debug such an
> issue. There's no way to figure this out from within postgres, one pretty much
> needs to look at stack traces.
>
> I think we should add a few wait events for log emission. I think it'd be good
> to have one wait event for each log destination.
>
> That's not perfect - we'd e.g. still not be able to debug where the logger
> process is stuck, due it not being in pg_stat_activity. But other processes
> reporting the wait event for writing to the logger process would be a pretty
> good hint.


+1.

Would it make sense to at the same time create a separate one for
syslog, or just use the same?

--
 Magnus Hagander
 Me: https://www.hagander.net/
 Work: https://www.redpill-linpro.com/