Re: Load spikes on 8.1.11

On Fri, Jul 18, 2008 at 9:58 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> "Gurjeet Singh" <singh(dot)gurjeet(at)gmail(dot)com> 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.

--
gurjeet[(dot)singh](at)EnterpriseDB(dot)com
singh(dot)gurjeet(at){ gmail | hotmail | indiatimes | yahoo }.com

EnterpriseDB http://www.enterprisedb.com

Mail sent from my BlackLaptop device