@Override
  public GetOpenTxnsResponse getOpenTxns() throws LockException {
    try {
      return getMS().getOpenTxns();
    } catch (TException e) {
      throw new LockException(ErrorMsg.METASTORE_COMMUNICATION_FAILED.getMsg(), e);
    }
  }
Start the heartbeater threadpool and return the task.
@param initialDelay time to delay before first execution, in milliseconds
@return heartbeater
ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DbTxnManager.java