Re: Possible solution for LIKE optimization

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>, PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Possible solution for LIKE optimization
Date: 2001-08-06 19:47:01
Message-ID: Pine.LNX.4.30.0108062140470.680-100000@peter.localdomain
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Tom Lane writes:

> On the other hand, LIKE *is* multibyte aware. So the hypothetical
> non-locale-aware comparison operators would need to be aware of
> multibyte character sets even though not aware of locale. And the
> "add one" operator that we postulated for the LIKE index optimization
> needs to be able to increment a multibyte character.

Both of these are not hard if you know how strcmp operates. It would also
be irrelevant whether "add one" to a multibyte character yields another
valid multibyte character. strcmp doesn't care.

--
Peter Eisentraut peter_e(at)gmx(dot)net http://funkturm.homeip.net/~peter

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