Which attribute in the postgresql.conf file this is set ?
I am running CentOS Linux, PG 8.4
Thanks! Arvind
From: Mladen Gogala <mgogala@vmsinfo.com> To: "pgsql-novice@postgresql.org" <pgsql-novice@postgresql.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