On Fri, Jul 18, 2008 at 10:15:42AM +0530, Gurjeet Singh wrote: > On Fri, Jul 18, 2008 at 10:05 AM, Gurjeet Singh <[EMAIL PROTECTED]> > wrote: > > > On Fri, Jul 18, 2008 at 9:58 AM, Tom Lane <[EMAIL PROTECTED]> wrote: > > > >> "Gurjeet Singh" <[EMAIL PROTECTED]> writes: > >> > During these spikes, in the 'top' sessions we see the 'idle' PG > >> > processes consuming between 2 and 5 % CPU, and since the box has 8 CPUS > >> (2 > >> > sockets and each CPU is a quad core Intel Xeon processors) and somewhere > >> > around 200 Postgres processes, the load spikes to above 200; and it does > >> > this very sharply. > >> > >> This looks like heavy contention for a spinlock. You need to get a > >> higher-level analysis of what's happening before anyone can say much > >> more than that. > >> > >> Note that 8.1 is pretty much ancient history as far as scalability to > >> 8-core hardware goes. You should probably consider updating to 8.3 > >> before investing too much time in tracking down what's happening. > >> If you can still show the problem on 8.3 then there would be some > >> interest in fixing it ... > > > > > > Upgrading is on the cards, but not as high priority as I would like it to > > be! This is a production box, and we desperatly need some respite from these > > spikes. > > > > Can you please elaborate on what high level diagnosis would you need? > > > > I just ran DROP SCHEMA _<slony schema> CASCADE; and it spiked again, on a > > very low loaded box!! > > > > Thanks for all you help. > > > > Would reducing the number of connections on the DB help in reducing the > spike?
Just generally, reducing the number of connections to the DB will help in reducing resource consumption. When you first get a chance, use or set up a test environment where you can test the upgrade to 8.3.latest. Cheers, David. -- David Fetter <[EMAIL PROTECTED]> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: [EMAIL PROTECTED] Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers