Re: BUG #13766: weird ts_headline/ts_vector/ts_query behaviour - Mailing list pgsql-bugs

On 10.11.2015 16:53, aslesha.akella@gmail.com wrote:
>
> We are trying to make text search for a word "goede" and "goed". It got the
> following results with different languages.
>

Hi

Do you use predefined text search configurations "english" and "dutch"?

If so and you do not change them, then "english" and "dutch"
configurations use English and Dutch stemming algorithms
(https://en.wikipedia.org/wiki/Stemming) and check for stop words. In
the following examples you can see how words are converted to lexems:

 > select to_tsvector('dutch', 'Goede vrijdag');
      to_tsvector
----------------------
  'goed':1 'vrijdag':2
(1 row)

 > select to_tsvector('dutch', 'Goed vrijdag');
      to_tsvector
----------------------
  'goed':1 'vrijdag':2
(1 row)

 > select to_tsvector('english', 'Goed vrijdag');
     to_tsvector
--------------------
  'go':1 'vrijdag':2
(1 row)

 > select to_tsvector('english', 'Goede vrijdag');
      to_tsvector
----------------------
  'goed':1 'vrijdag':2
(1 row)

The simple configuration do not use stemming algorithms. It only convert
input words to lower case lexems and exclude stop words.

You also can create ispell dictionary and use it. More information in
the documentation:
http://www.postgresql.org/docs/devel/static/textsearch-dictionaries.html
and good articles:
http://shisaa.jp/postset/postgresql-full-text-search-part-1.html
http://shisaa.jp/postset/postgresql-full-text-search-part-2.html
http://shisaa.jp/postset/postgresql-full-text-search-part-3.html

But I am not sure that I understood your question correctly.

--
Artur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company