Re: How to switch off Snowball stemmer for tsearch2?

On Wed, 22 Aug 2007, Dmitry Koterov wrote:

> Suppose I cannot add such synonyms, because:
>
> 1. There are a lot of surnames, cannot take care about all of them.
> 2. After adding a new surname I have to re-calculate all full-text indices,
> it costs too much (about 10 days to complete the recalculation).
>
> So, I neet exactly what I ast - switch OFF stem guessing if a word is not in
> the dictionary.

no problem, just modify pg_ts_cfgmap, which contains mapping
token - dictionaries.

if you change configuration you should rebuild tsvector and reindex.
10 days looks very suspicious.

>
> On 8/22/07, Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> wrote:
>>
>> 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(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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>

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