Re: Query performance over a large proportion of data

From: Tom Lane
Subject: Re: Query performance over a large proportion of data
Date: ,
Msg-id: 17476.1236730615@sss.pgh.pa.us
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In response to: Query performance over a large proportion of data  ("Steve McLellan")
List: pgsql-performance

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Query performance over a large proportion of data  ("Steve McLellan", )
 Re: Query performance over a large proportion of data  (Scott Marlowe, )
 Re: Query performance over a large proportion of data  ("Kevin Grittner", )
  Re: Query performance over a large proportion of data  (Tom Lane, )
 Re: Query performance over a large proportion of data  (Scott Marlowe, )
 Re: Query performance over a large proportion of data  (Tom Lane, )
 Re: Query performance over a large proportion of data  (Steve McLellan, )
 Re: Query performance over a large proportion of data  (Steve McLellan, )
  Re: Query performance over a large proportion of data  (Scott Marlowe, )
 Re: Query performance over a large proportion of data  (Steve McLellan, )
 Re: Query performance over a large proportion of data  (decibel, )
  Re: Query performance over a large proportion of data  (Matteo Beccati, )

"Steve McLellan" <> 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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