Date: Mon, 20 Jan 2003 21:32:25 -0800
From: Vernon Wu <vernonw@gatewaytech.com>
Subject: Re: performance question
In-reply-to: <20147.1043095100@sss.pgh.pa.us>
To: mlennert@club.worldonline.be, Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-sql@postgresql.org
Reply-To: vernonw@gatewaytech.com
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20/01/2003 12:38:20 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

>"Moritz Lennert" <mlennert@club.worldonline.be> writes:
>> One question I asked myself is whether the use of char(2) is the best
>> option.
>
>It may not be, particularly if you are running in a non-English locale.
>Comparisons will invoke the standard library routine strcoll(), which is
>depressingly slow in some locales, at least on some platforms.
>


In the case of selection operations involving multiple tables joined by userid that can be in various languages, is a 
potential performance trouble spot? Considering the number of tables anywhere from ten to twenty.


>> The column (and most others in the table) contains codes that
>> designate different characteristics (for ex. in a column 'sex' one would
>> find '1'=male, '2'=female).
>
>If you are using numeric codes you are surely better off storing them
>as integer or perhaps smallint (integer is less likely to create type
>mismatch headaches, though).  In the above example you are getting the
>worst of both worlds: there's no mnemonic value in your data entries,
>*and* you're paying for textual comparisons.
>
>			regards, tom lane
>
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