CREATE OR REPLACE FUNCTION ff_tsvector_add (v1 tsvector, v2 tsvector) RETURNS tsvector AS $$ BEGIN RETURN v1 || v2 ; END; $$ LANGUAGE plpgsql IMMUTABLE RETURNS NULL ON NULL INPUT; CREATE AGGREGATE ff_tsvector_agg ( basetype = tsvector, sfunc = ff_tsvector_add, stype = tsvector );