From: Josh Berkus <josh@agliodbs.com>
To: Alex Kretschmer <a_kretschmer@gmx.de>
Cc: pgsql-sql@postgresql.org
Subject: Re: postgres index on ILIKE
Date: Mon, 29 Sep 2003 10:09:31 -0700
Message-ID: <200309291009.31470.josh@agliodbs.com> (raw)
In-Reply-To: <3F7824A8.2010704@gmx.de>
References: <3F7824A8.2010704@gmx.de>
Alex,
> mydb=# explain select filename from neighbors where filename ilike
> '%test%'; QUERY PLAN
> -------------------------------------------------------------
> Seq Scan on neighbors (cost=0.00..17449.64 rows=774 width=37)
> Filter: ((filename)::text ~~* '%test%'::text)
I just looked at your query. What you have above is an "unanchored text
search", where you are looking for a snippet of text anywhere in the field.
Such a search *cannot* be indexed using a regular index.
Instead, you need to employ the TSearch full text searching module for
PostgreSQL.
hmmm ... the Tsearch home page appears to be down. Check out the readme in
your postgreSQL source code: PG_SOURCE/contrib/tsearch/readme
--
Josh Berkus
Aglio Database Solutions
San Francisco
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: josh@agliodbs.com, a_kretschmer@gmx.de
Subject: Re: postgres index on ILIKE
In-Reply-To: <200309291009.31470.josh@agliodbs.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox