syslog slowing the database?

From: Greg Spiegelberg <gspiegelberg(at)cranel(dot)com>
To: PgSQL Performance ML <pgsql-performance(at)postgresql(dot)org>, Postgres Admin List <pgsql-admin(at)postgresql(dot)org>
Subject: syslog slowing the database?
Date: 2004-03-09 20:29:43
Message-ID: 404E2937.4060604@cranel.com
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I've been waiting all day for a pg_restore to finish on a test system
identically configured as our production in hardware and software
with the exception prod is 7.3.5 and test is 7.4.1.

The file it's restoring from is about 8GB uncompressed from a
"pg_dump -b -F t" and after 2 hours the directory the database is in
contains only 1GB. iostat reported ~2000 blocks written every 2
seconds to the DB file system.

I turned syslog off to see if it was blocking anything and in the
past couple minutes 1GB has been restored and iostat reports ~35,000
blocks written every 2 seconds to the DB file system.

The system is completely idle except for this restore process. Could
syslog the culprit?

I turned syslog back on and the restore slowed down again. Turned
it off and it sped right back up.

Can anyone confirm this for me?

Greg

--
Greg Spiegelberg
Sr. Product Development Engineer
Cranel, Incorporated.
Phone: 614.318.4314
Fax: 614.431.8388
Email: gspiegelberg(at)Cranel(dot)com
Cranel. Technology. Integrity. Focus.

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