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Re: default locale considered harmful? (was Re: [GENERAL]

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Peter Eisentraut <peter_e(at)gmx(dot)net>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Andrew Sullivan <andrew(at)libertyrms(dot)info>,PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: default locale considered harmful? (was Re: [GENERAL]
Date: 2003-05-31 04:09:04
Message-ID: 200305310409.h4V494124130@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackers
Has the single-byte LIKE penalty been eliminated, so we don't need to
consider using C as the default locale for initdb, right?

If fixed, how was it done?

---------------------------------------------------------------------------

Peter Eisentraut wrote:
> Tom Lane writes:
> 
> > I recall someone floating a proposal that initdb should by default
> > initialize the database in C locale, not whatever-it-finds-in-the-
> > environment.  To get a non-C locale you'd have to give an explicit
> > command-line switch --- essentially, reversing the sense of the present
> > "initdb --no-locale" option.
> 
> If you're concerned about speed, let's think about fixing the real
> problems, not about disabling the feature altogether.  A while ago I
> proposed an easy solution that made LIKE use an index based on strxfrm
> order instead.  It was rejected on the grounds that it would prevent a
> future enhancement of the LIKE mechanism to use the locale-enabled
> collation order, but no one seems to be seriously interested in
> implementing that.  I still have the patch; we can reconsider it if you
> like.
> 
> (Btw., LIKE using the locale-enabled collation sequence is hardly going to
> work, because most locales compare strings backwards from the end to the
> start in the second pass, so something like LIKE 'foo%' can easily give
> inconsistent results, since you don't know what the end of the string
> really is.  It's better to think of pattern matching as
> character-by-character matching.)
> 
> -- 
> Peter Eisentraut   peter_e(at)gmx(dot)net
> 
> 
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-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

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