From: Tom Lane <tgl@sss.pgh.pa.us>
To: Steve McLellan <smclellan@mintel.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Query performance over a large proportion of data
Date: Tue, 10 Mar 2009 20:16:55 -0400
Message-ID: <17476.1236730615@sss.pgh.pa.us> (raw)
In-Reply-To: <1ca6422a7addad0207f758f54300dd0b.squirrel@semichrome.net>
References: <1ca6422a7addad0207f758f54300dd0b.squirrel@semichrome.net>
"Steve McLellan" <smclellan@mintel.com> writes:
> lc_messages = 'en_US.UTF-8'
> lc_monetary = 'en_US.UTF-8'
> lc_numeric = 'en_US.UTF-8'
> lc_time = 'en_US.UTF-8'
BTW, aside from the points already made: the above indicates that you
initialized your database in en_US.utf8 locale. This is not necessarily
a good decision from a performance standpoint --- you might be much
better off with C locale, and might even prefer it if you favor
ASCII-order sorting over "dictionary" sorting. utf8 encoding might
create some penalties you don't need too. This all depends on a lot
of factors you didn't mention; maybe you actually need utf8 data,
or maybe your application doesn't do many string comparisons and so
isn't sensitive to the speed of strcoll() anyway. But I've seen it
be a gotcha for people moving from MySQL, which AFAIK doesn't worry
about honoring locale-specific sort order.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, smclellan@mintel.com
Subject: Re: Query performance over a large proportion of data
In-Reply-To: <17476.1236730615@sss.pgh.pa.us>
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