Hi, thanks for your Answers. @Rémi Cura You suggest a kind of Full Text Search. I already had a try with the tsearch2 extension. The issue is to realize the similarity search. I have to use many OR statements with a low set of arguments. That significantly slows the FTS down. @Kevin Grittner I used my own trigger to store the tsvector of the sentences and I created a usual gist Index on them. What kind of functional Index would you suggest. Like i already told Rémi, I have to to use many OR statements with a low set of arguments, which heavy damages the perfance. Do you have a better idea? I usually used a query like this: The tiger is the largest cat species[http://en.wikipedia.org/wiki/Felidae], reaching a total body length of up to 3.3 m and weighing up to 306 kg. -------------------------------------------------------------------------------------------------------------------------------------------------- totsvector: '3.3':16 '306':22 'bodi':11 'cat':6 'kg':23 'largest':5 'length':12 'm':17 'reach':8 'speci':7 'tiger':2 'total':10 'weigh':19 (1 row) SELECT * FROM tablename WHERE vector @@ to_tsquery('speci & tiger & total & weigh') AND vector @@ to_tsquery('largest & length & m & reach') AND vector @@ to_tsquery('3.3 & 306 & bodi & cat & kg'); And thats very slow I didn't know that the pg_trgm Module provides KNN search. Janek Sendrowski -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
