Re: Neat trick

Hi Mladen,

Which attribute in the postgresql.conf file this is set ?

I am running CentOS Linux, PG 8.4

Thanks!
Arvind

________________________________
From: Mladen Gogala <mgogala(at)vmsinfo(dot)com>
To: "pgsql-novice(at)postgresql(dot)org" <pgsql-novice(at)postgresql(dot)org>
Sent: Tue, September 14, 2010 2:30:28 PM
Subject: [NOVICE] Neat trick

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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