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Neat trick

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
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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 
The Leader in Integrated Media Intelligence Solutions


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Subject: Re: transaction is read-only error
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Subject: transaction is read-only error

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