Re: like and optimization

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: robn(at)verdi(dot)et(dot)tudelft(dot)nl (Rob van Nieuwkerk)
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: like and optimization
Date: 2001-01-21 02:52:49
Message-ID: 8608.980045569@sss.pgh.pa.us
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robn(at)verdi(dot)et(dot)tudelft(dot)nl (Rob van Nieuwkerk) writes:
> But if anybody thinks that selects with LIKE on indexed columns with
> single-byte non-ASCII characters are working OK: they are not !! See my
> posting and following thread "7.0.3 reproduceable serious select error"
> from a couple of days ago.

Yes, we know :-(. That's why that optimization is currently disabled
for non-ASCII locales in 7.1. Juriy appears to be saying that it does
work OK in KOI8-R locale.

> I made a reproduceable example of things going wrong with a "en_US"
> locale which is the widely-used (single-byte) ISO-8859-1 Latin 1 charset.

en_US uses multi-pass collation rules. It's those collation rules, not
the charset per se, that causes the problem.

regards, tom lane

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