BEGIN
        IF (TG_OP = 'INSERT') THEN
		NEW.fts_name := to_tsvector(NEW.lang, NEW.name);
                -- NEW.fts_summary := to_tsvector(NEW.lang, NEW.fts_summary);            
		RETURN NEW;
        ELSIF (TG_OP = 'UPDATE') THEN
            IF OLD.name != NEW.name THEN 	
                -- NEW.fts_name := to_tsvector(NEW.lang, NEW.name);                   
            END IF;
            RETURN NEW;             
	END IF;
END;

ERROR: function to_tsvector(character varying, character varying) does not exist LINE  1 : SELECT to_tsvector( $ 1  , $ 2  ) ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts. QUERY: SELECT to_tsvector( $ 1  , $ 2  ) CONTEXT: PL/pgSQL function "trg_ins_upd_articles" line  3  at assignment

postgres=# \df to_tsvector
                         List of functions
   Schema   |    Name     | Result data type | Argument data types
------------+-------------+------------------+---------------------
 pg_catalog | to_tsvector | tsvector         | regconfig, text
 pg_catalog | to_tsvector | tsvector         | text