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Subject: Re: Docs off on ILIKE indexing? 
Date: Tue, 17 Jan 2006 15:44:30 +0100
Message-ID: <6BCB9D8A16AC4241919521715F4D8BCE6C7EB6@algol.sollentuna.se>
Thread-Topic: [HACKERS] Docs off on ILIKE indexing? 
Thread-Index: AcYaxyZc2OPs0ZGJQ763iGxQ9+0vEAArRyLg
From: "Magnus Hagander" <mha@sollentuna.net>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "pgsql-hackers" <pgsql-hackers@postgresql.org>

> > http://www.postgresql.org/docs/8.1/static/indexes-types.html
> > says:
> > The optimizer can also use a B-tree index for queries involving the=20
> > pattern matching operators LIKE, ILIKE, ~, and ~*, if the=20
> pattern is a=20
> > constant and is anchored to the beginning of the string -=20
> for example,=20
> > col LIKE 'foo%' or col ~ '^foo', but not col LIKE '%bar'.
>=20
> > But really, does it use indexes for ILIKE?
>=20
> That's pretty poorly phrased.  For ILIKE it'll only work if=20
> there's a prefix of the pattern that's not letters (and hence=20
> is unaffected by the case-folding issue).

Ahh. That explains it. Perfectly logical.
And yes, that's pretty poorly phrased - at least I didn't understand it
:-)

//Magnus