19 Changes in MySQL NDB Cluster 7.3.15 (5.6.34-ndb-7.3.15) (2016-10-18, General Availability)

MySQL NDB Cluster 7.3.15 is a new release of NDB Cluster, based on MySQL Server 5.6 and including features from version 7.3 of the NDB storage engine, as well as fixing a number of recently discovered bugs in previous NDB Cluster releases.

Obtaining MySQL NDB Cluster 7.3. MySQL NDB Cluster 7.3 source code and binaries can be obtained from https://dev.mysql.com/downloads/cluster/.

For an overview of changes made in MySQL NDB Cluster 7.3, see What is New in NDB Cluster 7.3.

This release also incorporates all bug fixes and changes made in previous NDB Cluster releases, as well as all bug fixes and feature changes which were added in mainline MySQL 5.6 through MySQL 5.6.34 (see Changes in MySQL 5.6.34 (2016-10-12, General Availability)).

Functionality Added or Changed

MySQL NDB ClusterJ: To help applications handle database errors better, a number of new features have been added to the ClusterJDatastoreException class:
- A new method, getCode(), returns code from the NdbError object.
- A new method, getMysqlCode(), returns mysql_code from the NdbError object.
- A new subclass, ClusterJDatastoreException.Classification, gives users the ability to decode the result from getClassification(). The method Classification.toString() gives the name of the error classification as listed in NDB Error Classifications.
(Bug #22353594)

Bugs Fixed

NDB Cluster APIs: Reuse of transaction IDs could occur when Ndb objects were created and deleted concurrently. As part of this fix, the NDB API methods lock_ndb_objects() and unlock_ndb_objects are now declared as const. (Bug #23709232)
Removed an invalid assertion to the effect that all cascading child scans are closed at the time API connection records are released following an abort of the main transaction. The assertion was invalid because closing of scans in such cases is by design asynchronous with respect to the main transaction, which means that subscans may well take some time to close after the main transaction is closed. (Bug #23709284)
A number of potential buffer overflow issues were found and fixed in the NDB codebase. (Bug #23152979)
When a data node has insufficient redo buffer during a system restart, it does not participate in the restart until after the other nodes have started. After this, it performs a takeover of its fragments from the nodes in its node group that have already started; during this time, the cluster is already running and user activity is possible, including DML and DDL operations.
During a system restart, table creation is handled differently in the DIH kernel block than normally, as this creation actually consists of reloading table definition data from disk on the master node. Thus, DIH assumed that any table creation that occurred before all nodes had restarted must be related to the restart and thus always on the master node. However, during the takeover, table creation can occur on non-master nodes due to user activity; when this happened, the cluster underwent a forced shutdown.
Now an extra check is made during system restarts to detect in such cases whether the executing node is the master node, and use that information to determine whether the table creation is part of the restart proper, or is taking place during a subsequent takeover. (Bug #23028418)
When restoring a backup taken from a database containing tables that had foreign keys, ndb_restore disabled the foreign keys for data, but not for the logs. (Bug #83155, Bug #24736950)
Several object constructors and similar functions in the NDB codebase did not always perform sanity checks when creating new instances. These checks are now performed under such circumstances. (Bug #77408, Bug #21286722)
An internal call to malloc() was not checked for NULL. The function call was replaced with a direct write. (Bug #77375, Bug #21271194)