To: "Steve McLellan" <smclellan@mintel.com>
cc: pgsql-performance@postgresql.org
Subject: Re: Query performance over a large proportion of data 
In-reply-to: <1ca6422a7addad0207f758f54300dd0b.squirrel@semichrome.net> 
References: <1ca6422a7addad0207f758f54300dd0b.squirrel@semichrome.net>
Comments: In-reply-to "Steve McLellan" <smclellan@mintel.com>
	message dated "Tue, 10 Mar 2009 16:12:17 -0500"
Date: Tue, 10 Mar 2009 20:16:55 -0400
Message-ID: <17476.1236730615@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

"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