@Transactional
  public void merge(Collection<ClusterConfigEntity> clusterConfigEntities) {
    merge(clusterConfigEntities, false);
  }
Merge the specified entities into the current persistence context.
@param clusterConfigEntities list of cluster configs to merge (not {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/ClusterDAO.java