text: CREATE TABLE readings (
    katakana text
  );
  
  INSERT INTO readings VALUES ('ポストグレスキューエル');
  INSERT INTO readings VALUES ('グルンガ');
  INSERT INTO readings VALUES ('ピージールンガ');
  INSERT INTO readings VALUES ('ピージーロジカル');
  
  CREATE INDEX pgrn_index ON readings
    USING pgroonga (katakana pgroonga_text_term_search_ops_v2);
  
  SET enable_seqscan = off;
  SET enable_indexscan = off;
  SET enable_bitmapscan = on;
  
  EXPLAIN (COSTS OFF)
  SELECT katakana
    FROM readings
   WHERE katakana &^~| ARRAY['po', 'gu'];
  
  SELECT katakana
    FROM readings
   WHERE katakana &^~| ARRAY['po', 'gu'];
  
  DROP TABLE readings;
  