Re: [HACKERS] Index greater than 8k - Mailing list pgsql-general

From Joshua D. Drake
Subject Re: [HACKERS] Index greater than 8k
Date
Msg-id 4548B593.4090104@commandprompt.com
Whole thread Raw
In response to Re: [HACKERS] Index greater than 8k  (Teodor Sigaev <teodor@sigaev.ru>)
List pgsql-general
Teodor Sigaev wrote:
>> We are trying to get something faster than ~ '%foo%';
>> Which Tsearch2 does not give us :)
>
> Hmm, why not with GIN? :) Although, right now GIN doesn't support prefix
> search, it's possible to use it.

Well they run 8.1 :)

Joshua D. Drake

>
> Brain storm method:
>
> Develop a dictionary which returns all substring for lexeme, for example
> for word foobar it will be 'foobar fooba foob foo fo oobar ooba oob oo
> obar oba ob bar ba ar'. And make GIN functional index over your column
> (to save disk space).
> So, your query will be looked as
> select ... where to_tsvector(text_column) @@ 'foo';
> Notices:
> Time of search in GIN weak depend on number of words (opposite to
> tsearch2/GiST), but insertion of row may be slow enough....
>


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