From: Greg Stark <gsstark@mit.edu>
To: Gavin Hamill <gdh@laterooms.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: pg 8.1.3, AIX, huge box, painfully slow.
Date: 07 Apr 2006 16:30:15 -0400
Message-ID: <871ww9m8mg.fsf@stark.xeocode.com> (raw)
In-Reply-To: <20060407204526.197afc19.gdh@laterooms.com>
References: <20060407185823.abe93017.gdh@laterooms.com>
<15233.1144435299@sss.pgh.pa.us>
<20060407204526.197afc19.gdh@laterooms.com>
Gavin Hamill <gdh@laterooms.com> writes:
> This is one hell of a moving target and I can't help but think I'm just
> missing something that's right in front of my nose, too close to see.
I'm assuming you compiled postgres yourself? Do you have the output from the
configure script? I'm wondering if it failed to find a good spinlock match for
the architecture. Not sure if that's really likely but it's a possibility.
Also, I'm pretty sure IBM has tools that would let you disable some of the
processors to see if maybe it's a shared memory bus issue. If I understand you
right the machine isn't in production yet? In which case I would get timing
information for a single processor, two processors, four processors, and eight
processors. If you see it max out and start dropping then that would point
towards a hardware/low level postgres issue like spinlocks or shared memory
rather than a high level database issue like stats.
--
greg
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: gsstark@mit.edu, gdh@laterooms.com
Subject: Re: pg 8.1.3, AIX, huge box, painfully slow.
In-Reply-To: <871ww9m8mg.fsf@stark.xeocode.com>
* 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