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Re: Adding Arabic dictionary for TSearch2.. to_tsvector('arabic'...) doesn't work..

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I finally got around to build a configuration but the results are not good at all and a bit odd.

Here is what I did:

I built the configuration with the hunspell + an Arabic simple dictionary (with just the stop words as an input) because I noticed that words not recognized will still get returned back.

Removed from the affix file : 
Flag long

CREATE TEXT SEARCH DICTIONARY hunar (
    TEMPLATE = ispell,
    DictFile = hunar,
    AffFile = hunar,
    StopWords = ar
);

CREATE TEXT SEARCH DICTIONARY ar_simple (
    TEMPLATE = pg_catalog.simple,      //Not sure what this is or does
    STOPWORDS = ar
);

CREATE TEXT SEARCH CONFIGURATION hunarconfig ( COPY = pg_catalog.english );

ALTER TEXT SEARCH CONFIGURATION hunarconfig
    ALTER MAPPING FOR asciiword, asciihword, hword_asciipart,
                      word, hword, hword_part
    WITH hunar, ar_simple;


Running : 

SELECT * FROM ts_debug('hunarconfig', '
وفي هذا الإطار أجرى رئيس الوزراء القطري الشيخ حمد بن جاسم بن جبر آل ثاني محادثات في لندن مع نظيره البريطاني غوردون براون تناولت الأوضاع الأمنية في الشرق الأوسط وتطرقت المباحثات إلى سبل تثبيت وقف إطلاق النار في قطاع غزة وعملية إعادة إعمار وبناء القطاع بعد الحرب الإسرائيلية الأخيرة.
');


returned odd results ( I think). Not many was recognized by the hunar dictionary and 
some stopwords where recognized by the latter dictionary ar_simple even though the same stopwords file was used in the hunar dictionary. Should I not expect the stopwords to be recognized by hunar and not ar_simple ? 

Here is a small sample that shows what I mean (with comments) : 


"وفي";         "{hunar,ar_simple}";     "hunar";              "{}"          // Recognized stop word by hunar dictionary

"هذا";          "{hunar,ar_simple}";     "ar_simple";        "{}"         // Recognized stop word but by ar_simple ? WHY?

"أجرى";       "{hunar,ar_simple}";     "ar_simple";        "{أجرى}"   // Not recognized by any, return


Is this not strange? Shouldn't the first dictionary (hunar) return the stopwords recognized and not ar_simple?


/ Moe











On Sat, Jan 10, 2009 at 11:14 AM, Andrew <archa@xxxxxxxxxxxxxx> wrote:
Mohamed wrote:
Thank you for you detailed answer. I have learned alot more about this stuff now :)
Your welcome :-)


As I see it accordingly to the results it's between Hunspell and Aspell. My Aspell version is 0.6 released 2006. The Hunspell was released in 2008. 

When I run the Postgres command \dFt I get the following list :
  • ispell 
  • simple
  • snowball
  • synonym
  • thesaurus

So I set up my dictionary with the ispell as a template and Hunspell/Aspell files. Now I just have one decision to make :)

Just another thing: 
If you want to support multiple language dictionaries for a single table, with each row associated to its own dictionary

Not really, since the two languages don't overlap, couldn't I set up two separate dictionaries and index against both on the whole table ? I think that's what Oleg was refering to. Not sure...
Neither am I, so when in doubt, try it out.  And let us know the results.


Thanks for all the help / Moe

Ps. I can't read Arabic so I can't have a look on the files to decide :O

In which case, assuming you do not have access to a friend who is able to read Arabic, either choose the file with the most entries (making assumption that more is better) or take the one that came with the dictionary (assuming that those two will be best matched) or if you still can't decide, flip a coin.  As you can't read Arabic, it is not as if you are in a position to put both files through their paces and test them against a word list, picking the one that gives you the best results for the type of words your text is likely to contain.

Cheers,

Andy



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