Rép. : Re: access time performance problem
Just to be sure:
Could it be a checkpoint?
Checkpoint is supposed to flush all data to disks at regular intervals, isn't it?
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Erwan DUROSELLE // SEAFRANCE DSI
Responsable Bases de Données // Databases Manager
Tel: +33 (0)1 55 31 59 70 // Fax: +33 (0)1 55 31 85 28
email: eduroselle@seafrance.fr
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"scott.marlowe" <scott.marlowe@ihs.com> 10/10/2002 17:34 >>>
On Thu, 10 Oct 2002, Louis-Marie Croisez wrote:
Sorry, bad url:
use this instead:
http://louis.croisez.free.fr/capture1.jpg
I'm gonna make a guess here that it's WAL activity, or log activity.
So first off, are you saving postgresql's output to a log? if so, try
logging to a different drive than your data drive or turning off logging
for a quick test.
If it's WAL writes that are causing the problem, you can either try to
change the settings for commit_delay and commit_siblings or symlinking the
pg_xlog directory somewhere else. If you aren't sure how to do that,
don't learn how to on a live production server with real data.
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I have tried to modify checkpoint_to and checkpoint_segment, commit_delay and commit_sibblings parameters, but without any effect.
Touching the different postgres parameters, I was not able to influence the height of the peaks (see captures1.jpg), nor the delay
between the peaks.
I wonder if that peaks are independent from postgres or not ? I have executed bonnie++, good results as expected.
Should I upgrade my kernel to the last one (2.4.19), and/or install the last postgres version?
----- Original Message -----
From: "Erwan DUROSELLE" <EDuroselle@seafrance.fr>
To: <pgsql-general@postgresql.org>
Sent: Thursday, October 10, 2002 5:58 PM
Subject: Rép. : Re: [GENERAL] access time performance problem
Just to be sure:
Could it be a checkpoint?
Checkpoint is supposed to flush all data to disks at regular intervals, isn't it?
-------------------------------------------------------------------------------
Erwan DUROSELLE // SEAFRANCE DSI
Responsable Bases de Données // Databases Manager
Tel: +33 (0)1 55 31 59 70 // Fax: +33 (0)1 55 31 85 28
email: eduroselle@seafrance.fr
-------------------------------------------------------------------------------
"scott.marlowe" <scott.marlowe@ihs.com> 10/10/2002 17:34 >>>
On Thu, 10 Oct 2002, Louis-Marie Croisez wrote:
Sorry, bad url:
use this instead:
http://louis.croisez.free.fr/capture1.jpg
I'm gonna make a guess here that it's WAL activity, or log activity.
So first off, are you saving postgresql's output to a log? if so, try
logging to a different drive than your data drive or turning off logging
for a quick test.
If it's WAL writes that are causing the problem, you can either try to
change the settings for commit_delay and commit_siblings or symlinking the
pg_xlog directory somewhere else. If you aren't sure how to do that,
don't learn how to on a live production server with real data.
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(send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
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