Re: Slow planning time for simple query

On 06/06/2018 09:59 AM, Jeremy Finzel wrote:
> Hello -
>
> 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);
>
> The actual execution time is sub-ms.

I am trying to sort out the various references to times so could you:

Show the EXPLAIN ANALYZE?

and ?

psql> \timing

psql> SELECT *
FROM table1
WHERE source_id IN (SELECT id FROM table2 WHERE customer_id = $1);

>
> We initially thought maybe catalog bloat?  But we were able to reindex
> all of the highly churned catalog tables, and I even did VACUUM FULL on
> pg_attribute and pg_statistic, to no avail.
>
> There are no custom settings for pg_attribute for the given tables either.
>
> Interestingly, the problem goes away on a SAN snapshot of the target system.
>
> Any ideas of what else we could try?  A PL function that caches the
> query plan works, but that is just a workaround.
>
> Thanks!
> Jeremy

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com