Re: Slow planning time for simple query

On Wed, Jun 6, 2018 at 12:12 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Jeremy Finzel <finzelj(at)gmail(dot)com> writes:
> > We have an odd scenario on one of our OLTP systems, which behaves the
> same
> > way on a streamer, of a 700-1000ms planning time for a query like this:
>
> > SELECT *
> > FROM table1
> > WHERE source_id IN (SELECT id FROM table2 WHERE customer_id = $1);
>
> Hm. Is this the first query executed in a session? If so maybe it's
> got something to do with populating caches and other session spin-up
> overhead.
>
> Another theory is it's some sort of locking issue. Turning on
> log_lock_waits, and setting deadlock_timeout to say 100ms, would help
> in investigating that.
>
> regards, tom lane
>

I have run it over and over with no improvement in the planning time, so I
don't thing it's first in session-related. I can only make it faster with
a pl function so far.

We have log_lock_waits on and nothing shows, and turning down
deadlock_timeout also doesn't do anything.

Thanks,
Jeremy