text: -- To load PGroonga
  SELECT pgroonga_command('status')::json->0->0;
  
  SHOW pgroonga.query_log_path;
  SET pgroonga.query_log_path = 'pgroonga.query.log';
  SHOW pgroonga.query_log_path;
  SET pgroonga.query_log_path = default;
  SHOW pgroonga.query_log_path;
  