Message-ID: <454B4CBD.7080204@archonet.com>
Date: Fri, 03 Nov 2006 14:05:49 +0000
From: Richard Huxton <dev@archonet.com>
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To: Richard Troy <rtroy@ScienceTools.com>
Cc: creimer@brturbo.com.br, pgsql-performance@postgresql.org
Subject: Re: Context switch storm
References: <Pine.LNX.4.33.0611030607350.1126-100000@denzel.in>
In-Reply-To: <Pine.LNX.4.33.0611030607350.1126-100000@denzel.in>
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Richard Troy wrote:
> On Fri, 3 Nov 2006, Richard Huxton wrote:
>> It's memory bandwidth issues on the older Xeons. If you search the
>> archives you'll see a lot of discussion of this. I'd have thought 8.1
>> would be better than 7.4 though.
> 
> Hmmm... I just checked; one of our production systems is a multi-cpu Xeon
> based system of uncertain age (nobody remember 'zactly). While we haven't
> seen this problem yet, it's scheduled to take over demo-duty shortly and
> it would be an embarassment if we had this trouble during a demo... Is
> there any easy way to tell if you're at risk?

Try:
- multiple clients
- query doing sorts that fit into work_mem

-- 
   Richard Huxton
   Archonet Ltd