Received: from localhost (postgresql.org [64.49.215.8])
	by postgresql.org (Postfix) with ESMTP id AC003475E85
	for <pgsql-sql@postgresql.org>; Mon, 26 Aug 2002 17:10:39 -0400 (EDT)
Received: from davinci.ethosmedia.com (davinci.ethosmedia.com [209.10.40.250])
	by postgresql.org (Postfix) with ESMTP id D2CC8475E41
	for <pgsql-sql@postgresql.org>; Mon, 26 Aug 2002 17:10:38 -0400 (EDT)
Received: from [66.219.92.2] (HELO chocolate-mousse)
	by davinci.ethosmedia.com (CommuniGate Pro SMTP 3.5.9)
	with ESMTP id 1624781; Mon, 26 Aug 2002 14:10:36 -0700
Content-Type: text/plain;
  charset="iso-8859-1"
From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: Jeff Boes <jboes@nexcerpt.com>, pgsql-sql@postgresql.org
Subject: Re: "reverse()" on strings
Date: Mon, 26 Aug 2002 14:11:01 -0700
X-Mailer: KMail [version 1.4]
References: <no.Yo.N.nN.0208261600250.2291-100000@business.com>
	<ake4lb$20ed$1@news.hub.org>
In-Reply-To: <ake4lb$20ed$1@news.hub.org>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Message-Id: <200208261411.01219.josh@agliodbs.com>
X-Virus-Scanned: by AMaViS new-20020517
X-Archive-Number: 200208/359
X-Sequence-Number: 9205

Jeff, h012,

> CREATE FUNCTION fn_strrev(text) returns text as '
> return reverse($_[0])
> ' language 'plperl' with (iscachable);

If you make that "WITH (ISCACHABLE, ISSTRICT)" the index will be faster to=
=20
update on columns which contain large numbers of NULLs.  "ISSTRICT" refers =
to=20
the fact that if the function receives a NULL, it will output a NULL, and=
=20
thus saves the parser the time running NULLs through the function.

Also, remember to use this index, you'll have to call the exact same functi=
on=20
in your queries.

--=20
-Josh Berkus
 Aglio Database Solutions
 San Francisco