void shutdownPool() throws SQLException {
    if (pool != null) {
      poolDone.set(true);
      drainQueue();
      pool.shutdownNow();
      try {
        while (!pool.awaitTermination(1, TimeUnit.SECONDS)) {
          drainQueue();
          LOG.debug("Slow fetch thread shutdown");
        }
      } catch (InterruptedException e) {
        throw new SQLException(e);
      }
      drainQueue();
      pool = null;
      threadsStarted = 0;
    }
  }
Set the specified schema to the resultset
@param colNames
@param colTypes
jdbc/src/java/org/apache/hive/jdbc/HiveQueryResultSet.java