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Re: Neat trick

From: Arvind Sharma <arvind321(at)yahoo(dot)com>
To: Mladen Gogala <mgogala(at)vmsinfo(dot)com>, "pgsql-novice(at)postgresql(dot)org" <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Neat trick
Date: 2010-09-15 14:33:46
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Lists: pgsql-novice
Hi Mladen,

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

I am running CentOS Linux, PG 8.4


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 The Leader in Integrated Media Intelligence Solutions

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  • Neat trick at 2010-09-14 21:30:28 from Mladen Gogala


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