Date: Tue, 4 Oct 2005 19:01:04 -0500
From: "Jim C. Nasby" <jnasby@pervasive.com>
To: Ron Peacetree <rjpeace@earthlink.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: Is There Any Way ....
Message-ID: <20051005000104.GO40138@pervasive.com>
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On Tue, Oct 04, 2005 at 07:33:47PM -0400, Ron Peacetree wrote:
> pg is _very_ stupid about caching.  Almost all of the caching is left
> to the OS, and it's that way by design (as post after post by TL has
> pointed out).
> 
> That means pg has almost no ability to take application domain
> specific knowledge into account when deciding what to cache.
> There's plenty of papers on caching out there that show that
> context dependent knowledge leads to more effective caching
> algorithms than context independent ones are capable of.
> 
> (Which means said design choice is a Mistake, but unfortunately
> one with too much inertia behind it currentyl to change easily.)
> 
> Under these circumstances, it is quite possible that an expert class
> human could optimize memory usage better than the OS + pg.

Do you have any examples where this has actually happened? Especially
with 8.x, which isn't all that 'stupid' about how it handles buffers?
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461