From: | Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> |
---|---|
To: | Bruce Momjian <bruce(at)momjian(dot)us> |
Cc: | Mark <Marek(dot)Balgar(at)seznam(dot)cz>, pgsql-hackers(at)postgresql(dot)org, Teodor Sigaev <teodor(at)sigaev(dot)ru> |
Subject: | Re: ts_rank |
Date: | 2011-10-13 11:23:14 |
Message-ID: | Pine.LNX.4.64.1110131514570.26195@sn.sai.msu.ru |
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Lists: | pgsql-hackers |
I'm sorry, my plane to Nepal is waiting me :) I'll be back in the
midst of November. In short, ts_rank is based only on frequencies of lexems
and doesn't count distance between query lexems. Also, it supports only
primitive queries.
Oleg
On Wed, 12 Oct 2011, Bruce Momjian wrote:
> Bruce Momjian wrote:
>> Mark wrote:
>>>> There's some potentially useful information here:
>>>> http://www.postgresql.org/docs/9.0/interactive/textsearch-controls.html#TEXTSEARCH-RANKING
>>>
>>> Thanks for reply. I was reading the documentation of PostgreSQL, but there
>>> it is not written the name of the used methods. Everywhere there is written,
>>> that ts_rank use standard ranking function. But it is difficult to say which
>>> is the standard function.
>>> Somewhere I found that it is maybe based on Vector space model and it seems
>>> to be truth, because in the code of tsrank.c is counted the frequency of
>>> words, but I am not sure of that :-(
>>
>> Oleg, Teodor, can you give me a description of how ts_rank decided how
>> to rank items? Thanks.
>
> Any news on this question?
>
>
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru)
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
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