Message-ID: <4DE60422.3090800@lerner.co.il>
Date: Wed, 01 Jun 2011 12:19:30 +0300
From: "Reuven M. Lerner" <reuven@lerner.co.il>
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To: Merlin Moncure <mmoncure@gmail.com>
CC: Steve Crawford <scrawford@pinpointresearch.com>,
	Alex Hunsaker <badalex@gmail.com>, pgsql-performance@postgresql.org
Subject: Re: Speeding up loops in pl/pgsql function
References: <4DDD358E.20307@lerner.co.il>
	<BANLkTinuiR=Txtn_dUeSbvvgcWZj9c2+iw@mail.gmail.com>
	<4DDD4E57.7070800@lerner.co.il>	<4DDD98B6.6080208@pinpointresearch.com>
	<BANLkTin8u2fM+RjE4Ao78v2W83V2Z9iHUA@mail.gmail.com>
	<BANLkTimU=O-vreTUTmC6TV+cA+TyqYqUnQ@mail.gmail.com>
	<BANLkTikoGpWS=S2EFruyWCkGxFoRk7Ms_A@mail.gmail.com>
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Hi, everyone.

First of all, thanks for all of your help several days ago.  The 
improvements to our program were rather dramatic (in a positive sense).

Based on the help that everyone gave, I'm working on something similar, 
trying to use regexp_replace to transform a string into the result of 
invoking a function on each character.  For example, I'd like to do the 
following:

regexp_replace('abc', '(.)', ascii(E'\\1')::text, 'g');

Unfortunately, the above invokes ascii() on the literal string E'\\1', 
rather than on the value of the backreference, which isn't nearly as 
useful.  I'd like to get '979899' back as a string.  And of course, once 
I can get back the value of ascii(), I figure that it should work for 
any function that I define.

Thanks again for any suggestions everyone might have.

(And if this should go to pgsql-general, then I'll understand.  If it 
helps, my alternative to regexp_replace is a super-slow function, akin 
to the one that I showed here last week.)

Reuven