Re: Fastest char datatype

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От Peter Eisentraut
Тема Re: Fastest char datatype
Дата
Msg-id 200907200902.34654.peter_e@gmx.net
обсуждение исходный текст
Ответ на Fastest char datatype  (Robert James <srobertjames@gmail.com>)
Ответы Re: Fastest char datatype  (Robert James <srobertjames@gmail.com>)
Список pgsql-performance
On Monday 20 July 2009 04:46:53 Robert James wrote:
> I'm storing a lot of words in a database.  What's the fastest format for
> finding them? I'm going to be doing a lot of WHERE w LIKE 'marsh%' and
> WHERE w IN ('m', 'ma').  All characters are lowercase a-z, no punctuation,
> no other alphabets.  By default I'm using varchar in utf-8 encoding, but
> was wondering if I could specificy something else (perhaps 7bit ascii,
> perhaps lowercase only) that would speed things up even further.

If your data is only lowercase a-z, as you say, then the binary representation
will be the same in all server-side encodings, because they are all supersets
of ASCII.

These concerns will likely be dominated by the question of proper indexing and
caching anyway.

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