Re: prefix search in tsearch

I applied a modified documentation patch (attached) that includes Oleg's
suggestions.

---------------------------------------------------------------------------

Oleg Bartunov wrote:
> Erik,
>
> I think it'd be more clear if you say not 'stemmed', but processed in
> according to configuration. Here is an example:
>
> $SHAREDIR/tsearch_data/my_synonyms.syn contains one line:
> one 1
>
>
> CREATE TEXT SEARCH DICTIONARY my_synonym (
> TEMPLATE = synonym,
> SYNONYMS = my_synonyms
> );
>
> ALTER TEXT SEARCH CONFIGURATION english
> ALTER MAPPING FOR asciiword
> WITH my_synonym, english_stem;
>
>
> test=# select 'one'::tsvector @@ to_tsquery('english','one:*');
> ?column?
> ----------
> f
> (1 row)
>
> because 'one' was processed by my_synonym dictionary.
>
> test=# select ts_debug('english','one');
> ts_debug
> ------------------------------------------------------------------------------
> (asciiword,"Word, all ASCII",one,"{my_synonym,english_stem}",my_synonym,{1})
> (1 row)
>
>
>
> On Tue, 31 Aug 2010, Erik Rijkers wrote:
>
> > [docs from cvs HEAD]
> >
> > I found the text-search documentation a little unclear about 'prefix search'; specifically, the
> > examples do not show that the so-called 'prefix' is first stemmed, before it is used as prefix.
> >
> > For instance, the following can be a little surprising:
> >
> > SELECT to_tsvector( 'postgraduate' ) @@ to_tsquery( 'postgres:*' );
> > ?column?
> > ----------
> > t
> > (1 row)
> >
> > Because prefix search is such an important functionality I think this should be better explained,
> > which I hope the attached doc-patch does.
> >
> > (In textsearch.sgml is another mention + example of prefix search, perhaps it should be extended a
> > little there too - which I'm happy to do as well, but I first wanted to see if you agree that it
> > is a little too obscure as it stands)
> >
> >
> > Erik Rijkers
> >
>
> 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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--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +