From: | Mladen Gogala <mgogala(at)vmsinfo(dot)com> |
---|---|
To: | "pgsql-novice(at)postgresql(dot)org" <pgsql-novice(at)postgresql(dot)org> |
Subject: | Neat trick |
Date: | 2010-09-14 21:30:28 |
Message-ID: | 4C8FE974.9000801@vmsinfo.com |
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Lists: | pgsql-novice |
I figured out how to speed up the sequential scans using "blockdev"
command. Essentially, this increases the read-ahead on the underlying
block device for the file system. It will change the read-ahead value
for the entire disk, even if there are several partitions on the disk.
The results are very promising. Unfortunately, I didn't take baseline
numbers and measure the effect with precision, but the look of it is
that things are much faster with the read-ahead set to 2048 instead of
the default 256. The read-ahead is measured in sectors read ahead by the
OS. The OS is Red Hat Linux, EL 5.5.
--
Mladen Gogala
Sr. Oracle DBA
1500 Broadway
New York, NY 10036
(212) 329-5251
http://www.vmsinfo.com
The Leader in Integrated Media Intelligence Solutions
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