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To: Manfred Koizar <mkoi-pg@aon.at>
Cc: shridhar_daithankar@persistent.co.in, pgsql-hackers@postgresql.org,
	pgsql-general <pgsql-general@postgresql.org>,
	pgsql-performance@postgresql.org
Subject: Re: [pgsql-performance] Large databases, performance 
In-reply-to: <a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com> 
References: <3D9C3E05.7070906@clearmetrix.com>
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	<a2n7qu0qen2ne1chalomdgt5n1etgb4uk3@4ax.com>
Comments: In-reply-to Manfred Koizar <mkoi-pg@aon.at>
	message dated "Wed, 09 Oct 2002 10:00:03 +0200"
Date: Wed, 09 Oct 2002 09:32:50 -0400
Message-ID: <19697.1034170370@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Manfred Koizar <mkoi-pg@aon.at> writes:
> here is an implementation of a set of user types: char3, char4,
> char10.

Coupla quick comments on these:

> CREATE FUNCTION charNN_lt(charNN, charNN)
>     RETURNS boolean
>     AS '$libdir/fixchar'
>     LANGUAGE 'c';

> bool
> charNN_lt(char *a, char *b)
> {
> 	return (strncmp(a, b, NN) < 0);
> }/*charNN_lt*/

These functions are dangerous as written, because they will crash on
null inputs.  I'd suggest marking them strict in the function
declarations.  Some attention to volatility declarations (isCachable
or isImmutable) would be a good idea too.

Also, it'd be faster and more portable to write the functions with
version-1 calling conventions.

Using the Makefile to auto-create the differently sized versions is
a slick trick...

			regards, tom lane