Re: EXTERNAL storage and substring on long strings

From: Scott Cain <cain(at)cshl(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Joe Conway <mail(at)joeconway(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: EXTERNAL storage and substring on long strings
Date: 2003-08-07 21:15:51
Message-ID: 1060290951.6795.38.camel@localhost.localdomain
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> snipped much discussion about EXTERNAL storage and substring speed

Joe and Tom,

Thanks for all of your help; I went back to my (nearly) production
database, and executed the `update feature set residues = residues
||'';` and then redid my benchmark. Here's a summary of the results:

substr in perl 0.83sec/op
substring on default text column 0.24sec/op
substring on EXTERNAL column 0.0069sec/op

There's that 2 orders of magnitude improvement I was looking for!

Thanks again,
Scott

--
------------------------------------------------------------------------
Scott Cain, Ph. D. cain(at)cshl(dot)org
GMOD Coordinator (http://www.gmod.org/) 216-392-3087
Cold Spring Harbor Laboratory

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