Re: [PERFORM] Cursors performance

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Bill Chandler <billybobc1210(at)yahoo(dot)com>
Cc: Kris Jurka <books(at)ejurka(dot)com>, pgsql-jdbc(at)postgresql(dot)org, pgsql-perform(at)postgresql(dot)org
Subject: Re: [PERFORM] Cursors performance
Date: 2004-07-13 17:08:57
Message-ID: 16994.1089738537@sss.pgh.pa.us
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Bill Chandler <billybobc1210(at)yahoo(dot)com> writes:
> One final clue before I go: if I change my wildcard to
> 'NEPOOL%' from 'NEPOOL%REAL%' my query completes much
> faster.

Could we see the exact queries and EXPLAIN ANALYZE output for both
cases? I'm wondering if the plan changes. I think that the planner
will believe that the latter pattern is significantly more selective
(how much more selective depends on exactly which PG version you're
using); if this results in a bad row-count estimate then a bad plan
could get picked.

regards, tom lane

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