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From: Andy Colson <andy@squeakycode.net>
To: Ryan Wexler <ryan@iridiumsuite.com>
To: pgsql-performance@postgresql.org
Subject: Re: performance on new linux box
Date: Tue, 13 Jul 2010 18:26:09 -0500
Message-ID: <4C3CF611.1090702@squeakycode.net> (raw)
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On 07/11/2010 03:02 PM, Ryan Wexler wrote:

>
> Well I got me a new raid card, MegaRAID 8708EM2, fully equipped with
> BBU and read and write caching are enabled.  It completely solved my
> performance problems.  Now everything is way faster than the previous
> server.  Thanks for all the help everyone.
>
> One question I do have is this card has a setting called Read Policy
> which apparently helps with sequentially reads.  Do you think that is
> something I should enable?
>
>
>

I would think it depends on your usage.  If you use clustered indexes (and understand how/when they help) then enabling it would help (cuz clustered is assuming sequential reads).

or if you seq scan a table, it might help (as long as the table is stored relatively close together).

But if you have a big db, that doesnt fit into cache, and you bounce all over the place doing seeks, I doubt it'll help.

-Andy



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