Thread: ts_rank
Could somebody explain me on which methods is based ts_rank and how it works? I would appreciate some articles, if exist. Thanks a lot for reply. Mark -- View this message in context: http://postgresql.1045698.n5.nabble.com/ts-rank-tp4384120p4384120.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com.
On Tue, May 10, 2011 at 6:21 AM, Mark <Marek.Balgar@seznam.cz> wrote: > Could somebody explain me on which methods is based ts_rank and how it works? > I would appreciate some articles, if exist. > Thanks a lot for reply. As far as I can tell, our documentation contains no useful information on this topic whatsoever. :-( -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
Robert Haas wrote: > Mark wrote: >> Could somebody explain me on which methods is based ts_rank and >> how it works? I would appreciate some articles, if exist. > As far as I can tell, our documentation contains no useful > information on this topic whatsoever. :-( There's some potentially useful information here: http://www.postgresql.org/docs/9.0/interactive/textsearch-controls.html#TEXTSEARCH-RANKING Although I don't know if it addresses Mark's question very well. Personally, I wonder how relevant ts_rank will be after knn-giswt is out.... -Kevin
On Thu, May 19, 2011 at 10:42 PM, Kevin Grittner <Kevin.Grittner@wicourts.gov> wrote: > Robert Haas wrote: >> Mark wrote: > >>> Could somebody explain me on which methods is based ts_rank and >>> how it works? I would appreciate some articles, if exist. > >> As far as I can tell, our documentation contains no useful >> information on this topic whatsoever. :-( > > There's some potentially useful information here: > > http://www.postgresql.org/docs/9.0/interactive/textsearch-controls.html#TEXTSEARCH-RANKING Ah, yes. I didn't read that carefully enough. That is useful, but it doesn't really explain how it works. > Although I don't know if it addresses Mark's question very well. > Personally, I wonder how relevant ts_rank will be after knn-giswt > is out.... I don't see why it would be any less useful... though if someone could find a way to KNN-ify such searches, I'm sure there would be a lot of very happy users. Seems pretty difficult, though. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
>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 :-( -- View this message in context: http://postgresql.1045698.n5.nabble.com/ts-rank-tp4384614p4414631.html Sent from the PostgreSQL - hackers mailing list archive at Nabble.com.
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. -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +
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? -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +
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@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(495)939-16-83, +007(495)939-23-83
Oleg Bartunov wrote: > 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. Thanks. Attached doc patch applied to head and 9.1.X. --------------------------------------------------------------------------- > > 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@sai.msu.su, http://www.sai.msu.su/~megera/ > phone: +007(495)939-16-83, +007(495)939-23-83 -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + diff --git a/doc/src/sgml/textsearch.sgml b/doc/src/sgml/textsearch.sgml new file mode 100644 index ef228e3..46db103 *** a/doc/src/sgml/textsearch.sgml --- b/doc/src/sgml/textsearch.sgml *************** ts_rank(<optional> <replaceable class="P *** 867,873 **** <listitem> <para> ! Standard ranking function.<!-- TODO document this better --> </para> </listitem> </varlistentry> --- 867,873 ---- <listitem> <para> ! Ranks vectors based on the frequency of their matching lexems. </para> </listitem> </varlistentry>