Re: Progress report on locale safe LIKE indexing

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>
Cc: PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Progress report on locale safe LIKE indexing
Date: 2001-08-18 10:47:06
Message-ID: Pine.LNX.4.30.0108181245160.677-100000@peter.localdomain
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Hiroshi Inoue writes:

> > An operator class text_binary_ops that does memcmp()-based comparison of
> > text data. The operators are named $<$ etc. for lack of a better idea.
> > That lack is further illustrated by the idea to name them "binary-<" etc.,
> > which wouldn't get through the parser, but it doesn't need to.
> >
> > The system will use such an index for the queries in question if the
> > locale is not "like-safe", in the terminology of the code (I'll end up
> > renaming that a little).
>
> This depends on the assumption that '=' is equivalent in
> any locale. Is it guaranteed ?
> For example, ( 'a' = 'A' ) isn't allowed in any locale ?

The whole point here is not to rely on '='. Instead we use a different
opclass which does "locale-safe" comparisons, as said above.

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

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