Date: Tue, 4 Oct 2005 15:19:33 -0500
From: "Jim C. Nasby" <jnasby@pervasive.com>
To: Ron Peacetree <rjpeace@earthlink.net>
Cc: Matthew Nuzum <mattnuzum@gmail.com>, newz@bearfruit.org,
	Postgresql Performance list <pgsql-performance@postgresql.org>
Subject: Re: Logarithmic change (decrease) in performance
Message-ID: <20051004201933.GT40138@pervasive.com>
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On Wed, Sep 28, 2005 at 06:03:03PM -0400, Ron Peacetree wrote:
> 1= keep more of the data set in RAM
> 2= increase the size of your HD IO buffers
> 3= make your RAID sets wider (more parallel vs sequential IO)
> 4= reduce the atomic latency of your RAID sets
> (time for Fibre Channel 15Krpm HD's vs 7.2Krpm SATA ones?)
> 5= make sure your data is as unfragmented as possible
> 6= change you DB schema to minimize the problem
> a= overall good schema design
> b= partitioning the data so that the system only has to manipulate a
> reasonable chunk of it at a time.

Note that 6 can easily swamp the rest of these tweaks. A poor schema
design will absolutely kill any system. Also of great importance is how
you're using the database. IE: are you doing any row-by-row operations?

> In many cases, there's a number of ways to accomplish the above.
> Unfortunately, most of them require CapEx.
> 
> Also, ITRW world such systems tend to have this as a chronic
> problem.  This is not a "fix it once and it goes away forever".  This
> is a part of the regular maintenance and upgrade plan(s). 

And why DBA's typically make more money that other IT folks. :)
-- 
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