On Mon, Apr 11, 2011 at 7:04 AM, Glyn Astill <glynast...@yahoo.co.uk> wrote: > Hi Guys, > > I'm just doing some tests on a new server running one of our heavy select > functions (the select part of a plpgsql function to allocate seats) > concurrently. We do use connection pooling and split out some selects to > slony slaves, but the tests here are primeraly to test what an individual > server is capable of. > > The new server uses 4 x 8 core Xeon X7550 CPUs at 2Ghz, our current servers > are 2 x 4 core Xeon E5320 CPUs at 2Ghz. > > What I'm seeing is when the number of clients is greater than the number of > cores, the new servers perform better on fewer cores.
O man, I completely forgot the issue I ran into in my machines, and that was that zone_reclaim completely screwed postgresql and file system performance. On machines with more CPU nodes and higher internode cost it gets turned on automagically and destroys performance for machines that use a lot of kernel cache / shared memory. Be sure and use sysctl.conf to turn it off: vm.zone_reclaim_mode = 0 -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
