1. Apache HDFS broker support HDFS HA and Hadoop kerberos authentication.
2. New Backup and Restore function. Use Fs Broker to backup your data to HDFS or restore them from HDFS.
3. Table-Level Privileges. Grant fine-grained privileges on table-level to specified user.
4. A lot of bugs fixed.
5. Performance improvement.
1. ix bugs in query layer.
2. remove some redundant code in BE
3. support specify multi helper node when starting FE
4. add proc 'cluster_load_statistic' to show load balance situation of Palo
