Re: Slow SQL query (14-15 seconds) - Mailing list pgsql-performance

Bruno Baguette <bruno.baguette@gmail.com> writes:
> I'm having a problem with this query (below) that takes betweend 14 and
> 15 seconds to run, which is too long for the end-user.
> I've done a EXPLAIN ANALYZE (below below) but I'm having difficulties to
> see which part of that query is taking so many times.

It's the repeatedly executed EXISTS subplan that's hurting you:

>                             SubPlan
>                               ->  Nested Loop  (cost=35.56..378.16
> rows=2 width=0) (actual time=16.511..16.511 rows=0 loops=818)

16.511 * 818 = 13505.998, so this is all but about 100 msec of the
runtime.  Can't tell if there's any easy way to improve it.  In
pre-8.4 releases trying to convert the EXISTS into an IN might help.

            regards, tom lane