Re: [HACKERS] LIKE fixed(?) for non-ASCII collation orders

From: Andreas Degert <ad(at)papyrus-gmbh(dot)de>
To: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] LIKE fixed(?) for non-ASCII collation orders
Date: 1999-12-31 14:56:25
Message-ID: 87vh5fgnvq.fsf@tarzan.noname.
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> I have just committed what I hope is the final solution for the problem
> of LIKE index optimization in non-ASCII locales. indxpath.c now
> generates both a lower and upper indexqual in all locales. For example,
> x LIKE 'foo%t'
> will create indexqual conditions
> x >= 'foo' AND x < 'fop'
> The "<" condition is omitted only if the code is unable to produce a
> string greater than the pattern's constant prefix.

the .. >= .. < .. condition will result in addtional matches, like 'fo ot',
so you still have to check with LIKE. I'm using such an expression
(without the additional LIKE) in an application, and it seems to match
at least everything that LIKE would match too (my users would have
complained about missing matches, but i never did a formal test or
evaluation).

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Sren Kreimeier 1999-12-31 15:17:55 How you can put over 20 GB on a single CD!
Previous Message Vince Vielhaber 1999-12-31 14:37:53 Re: [HACKERS] Happy New Year!