On Tue, Oct 20, 2015 at 12:34 PM, Jamie Koceniak <jkoceniak@xxxxxxxxxxxxx> wrote: > Version: > > ----------------------------------------------------------------------------------------------- > > PostgreSQL 9.1.14 on x86_64-unknown-linux-gnu, compiled by gcc (Debian > 4.7.2-5) 4.7.2, 64-bit > > Query Plan > > http://explain.depesz.com/s/4s37 > > Normally, this query takes around 200-300 ms to execute. > > However when several queries are run concurrently, query performance drops > to 30-60 seconds. Please define 'several'. Essential information here is a capture of 'top' and possibly 'perf top'. Also if the problem is storage related iostat can be very useful (or vmstat in a pinch) FYI you can use pgbench with -f mode to measure concurrency performance of any query. The very first thing to rule out is a storage bottleneck via measured iowait. Assuming that's the case, this problem is interesting if: *) Scaling is much worse than it should be *) You can confirm this on more modern postgres (interesting problems are only interesting if they are unsolved) merlin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
