Re: How to switch off Snowball stemmer for tsearch2?

On Wed, 22 Aug 2007, Dmitry Koterov wrote:

> Hello.
>
> We use ispell dictionaries for tsearch2 (ru_ispell_cp1251)..
> Now Snowball stemmer is also configured.
>
> How to properly switch OFF Snowball stemmer for Russian without turning off
> ispell stemmer? (It is really needed, because "Ivanov" is not the same as
> "Ivan".)
> Is it enough and correct to simply delete the row from pg_ts_dict or not?
>
> Here is the dump of pg_ts_dict table:

don't use dump, plain select would be  better. In your case, I'd
suggest to follow standard way - create synonym file like
ivanov ivanov
and use it before other dictionaries. Synonym dictionary will recognize
'Ivanov' and return 'ivanov'.

>
> dict_name    dict_init    dict_initoption    dict_lexize    dict_comment
> en_ispell    spell_init(internal)
>
DictFile=/usr/lib/ispell/english.med,AffFile=/usr/lib/ispell/english.aff,StopFile=/usr/share/pgsql/contrib/english.stop
> spell_lexize(internal,internal,integer)
> en_stem    snb_en_init(internal)    contrib/english.stop
> snb_lexize(internal,internal,integer)    English Stemmer. Snowball.
> ispell_template    spell_init(internal)
> spell_lexize(internal,internal,integer)    ISpell interface. Must have .dict
> and .aff files
> ru_ispell_cp1251    spell_init(internal)
>
DictFile=/usr/lib/ispell/russian.med,AffFile=/usr/lib/ispell/russian.aff,StopFile=/usr/share/pgsql/contrib/russian.stop.cp1251
> spell_lexize(internal,internal,integer)
> ru_stem_cp1251    snb_ru_init_cp1251(internal)
> contrib/russian.stop.cp1251    snb_lexize(internal,internal,integer)
> Russian Stemmer. Snowball. WINDOWS (cp1251) Encoding
> ru_stem_koi8    snb_ru_init_koi8(internal)    contrib/russian.stop
> snb_lexize(internal,internal,integer)    Russian Stemmer. Snowball. KOI8
> Encoding
> ru_stem_utf8    snb_ru_init_utf8(internal)    contrib/russian.stop.utf8
> snb_lexize(internal,internal,integer)    Russian Stemmer. Snowball. UTF8
> Encoding
> simple    dex_init(internal)        dex_lexize(internal,internal,integer)
> Simple example of dictionary.
> synonym    syn_init(internal)
> syn_lexize(internal,internal,integer)    Example of synonym dictionary
> thesaurus_template    thesaurus_init(internal)
> thesaurus_lexize(internal,internal,integer,internal)    Thesaurus template,
> must be pointed Dictionary and DictFile
>

     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