Re: Performance Issues on Opteron Dual Core

I installed Ubuntu 5.10 on the production server (64-Bit version), and sure
enough the peformance is like I expected. Opening up that table (320,000
records) takes 6 seconds, with CPU usage of one of the cores going up to
90% - 100% for the 6 seconds.
I assume only one core is being used per user / session / query?

Gregory


-----Original Message-----
From: Jim C. Nasby [mailto:jnasby@pervasive.com]
Sent: Thursday, May 04, 2006 12:47 PM
To: Gregory Stewart
Cc: Mark Kirkwood; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Performance Issues on Opteron Dual Core


All the machines I've been able to replicate this on have been SMP w2k3
machines running SP1. I've been unable to replicate it on anything not
running w2k3, but the only 'SMP' machine I've tested in that manner was
an Intel with HT enabled. I now have an intel with HT and running w2k3
sitting in my office, but I haven't had a chance to fire it up and try
it yet. Once I test that machine it should help narrow down if this
problem exists with HT machines (which someone on -hackers mentioned
they had access to and could do testing with). If it does affect HT
machines then I suspect that this is not an issue for XP...

On Tue, May 02, 2006 at 11:27:02PM -0500, Gregory Stewart wrote:
> Jim,
>
> Have you seen this happening only on W2k3? I am wondering if I should try
> out 2000 Pro or XP Pro.
> Not my first choice, but if it works...
>
>
>
> -----Original Message-----
> From: Jim C. Nasby [mailto:jnasby@pervasive.com]
> Sent: Tuesday, May 02, 2006 3:29 PM
> To: Mark Kirkwood
> Cc: Gregory Stewart; pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] Performance Issues on Opteron Dual Core
>
>
> On Sun, Apr 30, 2006 at 10:59:56PM +1200, Mark Kirkwood wrote:
> > Pgadmin can give misleading times for queries that return large result
> > sets over a network, due to:
> >
> > 1/ It takes time to format the (large) result set for display.
> > 2/ It has to count the time spent waiting for the (large) result set to
> > travel across the network.
> >
> > You aren't running Pgadmin off the dev server are you? If not check your
> > network link to dev and prod  - is one faster than the other? (etc).
> >
> > To eliminate Pgadmin and the network as factors try wrapping your query
> > in a 'SELECT count(*) FROM (your query here) AS a', and see if it
> > changes anything!
>
> FWIW, I've found problems running PostgreSQL on Windows in a multi-CPU
> environment on w2k3. It runs fine for some period, and then CPU and
> throughput drop to zero. So far I've been unable to track down any more
> information than that, other than the fact that I haven't been able to
> reproduce this on any single-CPU machines.
> --
> Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
> Pervasive Software      http://pervasive.com    work: 512-231-6117
> vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461
>
>
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--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461


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