7.2b2 problem using like 'XXX%' sequential scan

From: Giuseppe Tanzilli - CSF <g(dot)tanzilli(at)gruppocsf(dot)com>
To: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: 7.2b2 problem using like 'XXX%' sequential scan
Date: 2001-11-14 11:26:17
Message-ID: 3BF254D9.9040300@gruppocsf.com
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Ciao,
I'm testing 7.2b2 and I see it is much slower when I use like on column
with indexes,
the explain sais it is a sequantial scan (same as 7.1.3), but the time
it get to complete is much longer.

I got the problem only on SMP machine:
explain on 7.1.3 say it is a seq scan with cost 18837
explain on 7.2b2 say it is a seq scan 22.5

on single cpu 7.2b2 says:
Index scan with cost 29 and it is very fast!!

All platform are linux/i386 using redhat 7.2 and latest libraries

I'm testing latest snapshot just now.

thanks

--
-------------------------------------------------------
Giuseppe Tanzilli g(dot)tanzilli(at)gruppocsf(dot)com
CSF Sistemi srl phone ++39 0775 7771
Via del Ciavattino
Anagni FR
Italy

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