From: Tom Lane <tgl@sss.pgh.pa.us>
To: Yantao Shi <y.shi@larc.nasa.gov>
Cc: pgsql-performance@postgresql.org
Subject: Re: wildcard search performance with "like"
Date: Tue, 17 Jan 2006 16:01:33 -0500
Message-ID: <21504.1137531693@sss.pgh.pa.us> (raw)
In-Reply-To: <43CD4CE5.3020506@larcb.ecs.nasa.gov>
References: <43CD4CE5.3020506@larcb.ecs.nasa.gov>
Yantao Shi <y.shi@larc.nasa.gov> writes:
> testdbspc=# explain select file_name from catalog where file_name like
> 'MOD04_L2.A2005311.%.004.2005312013%.hdf';
> QUERY PLAN
> Seq Scan on catalog (cost=0.00..429.00 rows=1 width=404)
> Filter: (file_name ~~ 'MOD04_L2.A2005311.%.004.2005312013%.hdf'::text)
> (2 rows)
I'm betting you are using a non-C locale. You need either to run the
database in C locale, or to create a special index type that is
compatible with LIKE searches. See
http://www.postgresql.org/docs/8.1/static/indexes-opclass.html
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, y.shi@larc.nasa.gov
Subject: Re: wildcard search performance with "like"
In-Reply-To: <21504.1137531693@sss.pgh.pa.us>
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