Re: pg_stat_activity showing non-existent processes

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Jerry Sievers <jerry(at)jerrysievers(dot)com> writes:
> > At any rate; I'm wondering what possible causes might be responsible
> > for pg_stat_activity's underlying functions to lose track of the valid
> > process list?
>
> It sounds like the stats collector missed a few "backend quit"
> messages. This isn't real surprising: the stats messaging mechanism is
> intentionally designed to drop messages under severe load, rather than
> slow down backends.

Tom, I appreciate your comments on this.

> We recently put in a filter that prevents reporting pg_stat_activity
> lines for backends that are dead according to the up-to-date list in
> shared memory. I don't think that's in 8.0.3 though.

This machine is going to be upgraded to 8.1 ASAP.

In the meantime, I may adjust the cron run time for the batch job that
terminates these sessions in case it's running concurrently with other
batch traffic.

I believe the thing runs hourly at the 00 minute and this may likely
be a time that we're kicking off all sorts of other jobs too.

> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
>
> http://archives.postgresql.org
>

--
-------------------------------------------------------------------------------
Jerry Sievers 305 854-3001 (home) WWW ECommerce Consultant
305 321-1144 (mobile http://www.JerrySievers.com/