Java connectors for MySQL Cluster.  The MySQL Cluster distribution now includes 2 new Java user APIs, ClusterJ and ClusterJPA. ClusterJ is an object-relational interface in a manner similar to that of Java persistence frameworks such as Hibernate. Cluster JPA is a reimplementation of OpenJPA. ClusterJ uses a backend library (NdbJTie) that provides access to the NDB storage engine without using a MySQL Server connection or JDBC. ClusterJPA also uses NdbJTie when it improves performance, but can also process complex queries using JDBC and a MySQL Server connection, where it can take advantage of the MySQL query optimizer.

ClusterJ and Cluster JPA can also be made to work with recent MySQL Cluster NDB 7.0 releases although the necessary library and JAR files are included only in MySQL Cluster NDB 7.1.1 and later.

MySQL Cluster information database (ndbinfo).  The ndbinfo information database makes it possible to obtain real-time characteristics of a MySQL Cluster by issuing queries from the mysql client or other MySQL client applications. ndbinfo provides metadata specific to MySQL Cluster similarly to how the INFORMATION_SCHEMA database provides metadata for the standard MySQL Server. This eliminates much of the need to read log files, issue REPORT or DUMP commands in the ndb_mgm client, or parse the output of ndb_config in order to get configuration and status information from a running MySQL Cluster.

For more information, see Section 5.8, “The ndbinfo MySQL Cluster Information Database”.

Native support for default column values.  Starting with MySQL Cluster NDB 7.1.0, default values for table columns are stored in the NDB kernel rather than by the MySQL server as was done previously. This means that inserts on tables having column value defaults can be smaller and faster than before, because less data must be sent from SQL nodes to NDBCLUSTER.

Tables created using previous MySQL Cluster releases can still be used in MySQL Cluster 7.1.0 and later; however, they do not support native default values until they are upgraded. You can upgrade a table with non-native default values to support native default values using an offline ALTER TABLE statement.

Further enhancements based on this work that we hope to implement in future MySQL Cluster releases include the following:

--nowait-nodes option for management servers.  It is now possible to configure a cluster with two management servers, but to start the cluster using only one of them by starting the management node daemon with the --nowait-nodes option. The other management server can then be started at a later time to join the running MySQL Cluster.

Improved lock handling for primary key lookups on BLOB tables.  A MySQL Cluster table stores all but the first 256 bytes of any BLOB or TEXT column values in a separate BLOB table; when executing queries against such tables, a shared lock is obtained. Prior to MySQL Cluster NDB 7.1.1, when the query used a primary key lookup and took place within a transaction, the lock was held for the duration of the transaction, even after no more data was being read from the NDB table. Now in such cases, the lock is released when all BLOB data associated with the table has been read. (Bug#49190)

Heartbeat thread policy and priority.  Beginning with MySQL Cluster NDB 7.1.2, a new configuration parameter HeartbeatThreadPriority makes it possible to set the policy and the priority for the heartbeat thread on management and API nodes.

Improved access to partitioning information.  The ndb_desc utility now provides additional information about the partitioning of data stored in MySQL Cluster. Beginning with MySQL Cluster NDB 7.1.2, the --blob-info option causes this program to include partition information for BLOB tables in its output. Also beginning with MySQL Cluster NDB 7.1.2, the --extra-node-info option causes ndb_desc to include information about data distribution (that is, which table fragments are stored on which data nodes). Each of these options also requires the use of the --extra-partition-info option.

Information about partition-to-node mappings can also be obtained using the Table::getFragmentNodes() method, also added in MySQL Cluster NDB 7.1.2.

Replication attribute promotion and demotion.  Beginning with MySQL Cluster NDB 7.1.3, MySQL Cluster Replication supports attribute promotion and demotion when replicating between columns of different but similar types on the master and the slave. For example, it is possible to promote an INT column on the master to a BIGINT column on the slave, and to demote a TEXT column to a VARCHAR column.

The implementation of type demotion distinguishes between lossy and non-lossy type conversions, and their use on the slave can be controlled by setting the slave_type_conversions global server system variable.

For more information, see Attribute promotion and demotion (MySQL Cluster).

Change in ndbinfo database.  The experimental ndbinfo.pools table was removed from ndbinfo in MySQL Cluster NDB 7.1.3. Applications which used this table can and should be rewritten to use other ndbinfo tables. For more information, see Section 5.8.8, “The ndbinfo pools Table”.