Re: Tuning to speed select

On Wed, Aug 09, 2006 at 03:46:38PM +0200, Martijn van Oosterhout wrote:
> On Wed, Aug 09, 2006 at 09:19:31AM -0400, Tom Laudeman wrote:
> > Is there a tuning parameter I can change to increase speed of selects?
> > Clearly, there's already some buffering going on since selecting an
> > indexed ~50,000 records takes 17 seconds on the first try, and only 0.5
> > seconds on the second try (from pgsql).
>
> Your OS is probably buffering, 1GB of RAM holds a lot of data. You can
> try increasing the shared_buffers parameter, but if the delay is
> getting data from the disk, that won't really help you.

If most of your queries use the same index then clustering on that
index might speed up initial (i.e., not-cached) queries by reducing
the number of disk pages that need to be read. See the documentation
for more information.

http://www.postgresql.org/docs/8.1/interactive/sql-cluster.html

--
Michael Fuhr