Date: Tue, 4 Oct 2005 16:01:37 -0500
From: "Jim C. Nasby" <jnasby@pervasive.com>
To: Richard Huxton <dev@archonet.com>
Cc: xchris <lyralyra@fastmail.fm>, pgsql-performance@postgresql.org
Subject: Re: Lists or external TABLE?
Message-ID: <20051004210137.GZ40138@pervasive.com>
References: <1128071781.8112.32.camel@lyra> <433D06AB.3020409@archonet.com>
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On Fri, Sep 30, 2005 at 10:34:35AM +0100, Richard Huxton wrote:
> xchris wrote:
> >
> >Let's suppose i need to add an info about addresses (which includes
> >country,city,cap....etc etc).
> >Addresses can vary from 1 to 20 entries..
> >
> >Talking about performance is it better to include a list of addresses in
> >TABLE A or is it better to create an external TABLE B?
> 
> Don't optimise before you have to.
> 
> Do the addresses belong in "A"? If so, put them there. On the other 
> hand, if you want items in "A" to have more than one address, or to 
> share addresses then clearly you will want a separate address table. 
> It's difficult to say more without a clear example of your requirements.
> 
> Even if you choose to alter your design for performance reasons, you 
> should make sure you run tests with realistic workloads and hardware. 
> But first, trust PG to do its job and design your database according to 
> the problem requirements.

On top of what Richard said, 5000 rows is pretty tiny. Even if each row
was 1K wide, that's still only 5MB.

Also, if from a data-model standpoint it doesn't matter which way you
go, I suggest looking at what it will take to write queries against both
versions before deciding. I tend to stay away from arrays because
they tend to be harder to query against.
-- 
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