To: "Mario Weilguni" <mweilguni@sime.com>
Cc: <valiouk@yahoo.co.uk>,  "Jay" <arrival123@gmail.com>,
	<pgsql-performance@postgresql.org>
Subject: Re: Using PK value as a String
In-Reply-To: <48A15ECF.5030203@sime.com> (Mario Weilguni's message of "Tue\,
	12 Aug 2008 11\:58\:39 +0200")
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References: <18986.60888.qm@web25807.mail.ukl.yahoo.com>
	<48A15ECF.5030203@sime.com>
From: Gregory Stark <stark@enterprisedb.com>
Organization: EnterpriseDB
Date: Tue, 12 Aug 2008 13:51:36 +0100
Message-ID: <87od3ywg4n.fsf@oxford.xeocode.com>
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"Mario Weilguni" <mweilguni@sime.com> writes:

> UUID is already a surrogate key not a natural key, in no aspect better than a
> numeric key, just taking a lot more space.
>
> So why not use int4/int8?

The main reason to use UUID instead of sequences is if you want to be able to
generate unique values across multiple systems. So, for example, if you want
to be able to send these userids to another system which is taking
registrations from lots of places. Of course that only works if that other
system is already using UUIDs and you're all using good generators.

You only need int8 if you might someday have more than 2 *billion* users...
Probably not an urgent issue.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com
  Ask me about EnterpriseDB's Slony Replication support!