Re: How to switch off Snowball stemmer for tsearch2?

Oleg Bartunov <oleg@xxxxxxxxxx> · Wed, 22 Aug 2007 23:33:04 +0400 (MSD)

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@xxxxxxxxxx> 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@xxxxxxxxxx, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83

---------------------------(end of broadcast)---------------------------
TIP 1: if posting/reading through Usenet, please send an appropriate
       subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your
       message can get through to the mailing list cleanly

	Regards,
		Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@xxxxxxxxxx, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83

---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster