From: Alexander Staubo <alex@purefiction.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Susan Russo <russo@morgan.harvard.edu>
Cc: pgsql-performance@postgresql.org
Cc: harvsys@morgan.harvard.edu
Subject: Re: specific query (not all) on Pg8 MUCH slower than Pg7
Date: Tue, 8 May 2007 16:59:30 +0200
Message-ID: <88daf38c0705080759o2e5771c3qdf1b34baa581fc53@mail.gmail.com> (raw)
In-Reply-To: <1160.1178635705@sss.pgh.pa.us>
References: <200705081418.l48EIY8V026360@larrys.harvard.edu>
<1160.1178635705@sss.pgh.pa.us>
On 5/8/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> You're not getting the indexscan optimization of the LIKE clause, which
> is most likely due to having initdb'd the 8.1 installation in something
> other than C locale. You can either redo the initdb in C locale (which
> might be a good move to fix other inconsistencies from the 7.3 behavior
> you're used to) or create a varchar_pattern_ops index on the column(s)
> you're using LIKE with.
Given the performance implications of setting the wrong locale, and
the high probability of accidentally doing this (I run my shells with
LANG=en_US.UTF-8, so all my databases have inherited this locale), why
is there no support for changing the database locale after the fact?
# alter database test set lc_collate = 'C';
ERROR: parameter "lc_collate" cannot be changed
Alexander.
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To: pgsql-performance@postgresql.org
Cc: alex@purefiction.net, tgl@sss.pgh.pa.us, russo@morgan.harvard.edu, harvsys@morgan.harvard.edu
Subject: Re: specific query (not all) on Pg8 MUCH slower than Pg7
In-Reply-To: <88daf38c0705080759o2e5771c3qdf1b34baa581fc53@mail.gmail.com>
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