From: Ron <rjpeace@earthlink.net>
To: Mark Lewis <mark.lewis@mir3.com>
To: pgsql-performance@postgresql.org
Subject: Re: help tuning queries on large database
Date: Wed, 11 Jan 2006 01:03:48 -0500
Message-ID: <7.0.1.0.2.20060111005534.0378a630@earthlink.net> (raw)
In-Reply-To: <1136939286.22590.27.camel@archimedes>
References: <FC9B7CC4-F469-4BF5-8862-332E6C26BEA5@pobox.com>
<7.0.1.0.2.20060108160633.026bd358@earthlink.net>
<1136939286.22590.27.camel@archimedes>
At 07:28 PM 1/10/2006, Mark Lewis wrote:
>Ron,
>
>A few days back you mentioned:
>
> > Upgrade your kernel to at least 2.6.12
> > There's a known issue with earlier versions of the 2.6.x kernel and
> > 64b CPUs like the Opteron. See kernel.org for details.
> >
>
>I did some searching and couldn't find any obvious mention of this issue
>(I gave up after searching through the first few hundred instances of
>"64" in the 2.6.12 changelog).
>
>Would you mind being a little more specific about which issue you're
>talking about? We're about to deploy some new 16GB RAM Opteron DB
>servers and I'd like to check and make sure RH backported whatever the
>fix was to their current RHEL4 kernel.
There are 3 issues I know about in general:
1= As Peter Royal noted on this list, pre 12 versions of 2.6.x have
problems with RAM of >= 4GB.
2= Pre 12 versions on 2.6.x when running A64 or Xeon 64b SMP seem to
be susceptible to "context switch storms".
3= Physical and memory IO is considerably improved in the later
versions of 2.6.x compared to 2.6.11 or earlier.
Talk to a real Linux kernel guru (I am not) for details and specifics.
Ron
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: rjpeace@earthlink.net, mark.lewis@mir3.com
Subject: Re: help tuning queries on large database
In-Reply-To: <7.0.1.0.2.20060111005534.0378a630@earthlink.net>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox