Re: tsearch2 dictionary that indexes substrings?

On Fri, 20 Apr 2007, Tilmann Singer wrote:

> Hi,
>
> In this http://archive.netbsd.se/?ml=pgsql-hackers&a=2006-10&t=2475028
> thread Teodor Sigaev describes a way to make tsearch2 index substrings
> of words:
>
>> 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'
>
> Did anyone do that already?

AFAIK, no

>
> If I understand it correctly such a dictionary would require to write
> a custom C component - is that correct? Or could I get away with
> writing a plpgsql function that does the above and hooking that
> somehow into the tsearch2 config?

You need to write C-function, see example in
http://www.sai.msu.su/~megera/postgres/fts/doc/fts-intdict-xmp.html

     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83