Re: like and optimization - Mailing list pgsql-hackers

From Tom Lane
Subject Re: like and optimization
Date
Msg-id 8608.980045569@sss.pgh.pa.us
Whole thread Raw
In response to Re: like and optimization  (robn@verdi.et.tudelft.nl (Rob van Nieuwkerk))
List pgsql-hackers
robn@verdi.et.tudelft.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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