Re: efficiency of wildcards at both ends

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От Jasen Betts
Тема Re: efficiency of wildcards at both ends
Дата
Msg-id js402l$pde$1@reversiblemaps.ath.cx
обсуждение исходный текст
Ответ на efficiency of wildcards at both ends  (Sam Z J <sammyjiang721@gmail.com>)
Список pgsql-general
On 2012-06-20, Sam Z J <sammyjiang721@gmail.com> wrote:
> --0016e6d999db24c4c704c2ea7a97
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi all
>
> I'm curious how is wildcards at both ends implemented, e.g. LIKE '%str%'
> How efficient is it if that's the only search criteria against a large
> table? how much does indexing the column help

fulltextsearch can be abused with a custom lexer that fragments the string in every possible
way and that can be matched against, but not using LIKE.

Works OK on tables with tens of thaousands of rows haven't tried it on
larger rows.


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