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Date: Fri, 22 Feb 2008 18:10:18 +1300
From: Mark Kirkwood <markir@paradise.net.nz>
Subject: Re: 4s query want to run faster
In-reply-to: <dcc563d10802211516x65e80eb4o3d9975e626b3a760@mail.gmail.com>
To: Scott Marlowe <scott.marlowe@gmail.com>
Cc: Adonias Malosso <malosso@gmail.com>, Claus Guttesen <kometen@gmail.com>,
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Scott Marlowe wrote:
>
> effective_cache_size is pretty easy to set, and it's not real
> sensitive to small changes, so guesstimation is fine where it's
> concerned.  Basically, let your machine run for a while, then  add the
> cache and buffer your unix kernel has altogether (top and free will
> tell you these things).  If you're running other apps on the server,
> make a SWAG (scientific wild assed guess) how much the other apps are
> pounding on the kernel cache / buffer and set effective_cache_size to
> how much you think postgresql is using of the total and set it to
> that.
>   

FWIW - The buffered|cached may well be called something different if you 
are not on Linux (I didn't see any platform mentioned - sorry if I 
missed it) - e.g for Freebsd it is "Inactive" that shows what the os is 
caching and "Cached" actually means something slightly different... (yep 
that's caused a lot of confusion in the past...)

Cheers

Mark