Changes in MySQL NDB Cluster 7.6.16 (5.7.32-ndb-7.6.16) (2020-10-20, General Availability)

• Deprecation and Removal Notes

• Bugs Fixed

Deprecation and Removal Notes

• NDB Cluster APIs: Support for Node.js has been removed in this release.

  Node.js continues to be supported in NDB Cluster 8.0 only. (Bug #31781948)

• NDB Client Programs: Effective with this release, the MySQL NDB Cluster Auto-Installer (ndb_setup.py) has been deprecated and is subject to removal in a future version of NDB Cluster. (Bug #31888835)

• ndbmemcache: ndbmemcache is deprecated in this release of NDB Cluster, and is scheduled for removal in the next release. (Bug #31876970)

Bugs Fixed

• Packaging: The Dojo library included with NDB Cluster has been upgraded to version 1.15.4. (Bug #31559518)

• NDB Cluster APIs: In certain cases, the Table::getColumn() method returned the wrong Column object. This could happen when the full name of one table column was a prefix of the name of another, or when the names of two columns had the same hash value. (Bug #31774685)

• NDB Cluster APIs: It was possible to make invalid sequences of NDB API method calls using blobs. This was because some method calls implicitly cause transaction execution inline, to deal with blob parts and other issues, which could cause user-defined operations not to be handled correctly due to the use of a method executing operations relating to blobs while there still user-defined blob operations pending. Now in such cases, NDB raises a new error 4558 Pending blob operations must be executed before this call. (Bug #27772916)

• After encountering the data node in the configuration file which used NodeGroup=65536, the management server stopped assigning data nodes lacking an explicit NodeGroup setting to node groups. (Bug #31825181)

• In some cases, QMGR returned conflicting NDB engine and MySQL server version information, which could lead to unplanned management node shutdown. (Bug #31471959)

• During different phases of the restore process, ndb_restore used different numbers of retries for temporary errors as well as different sleep times between retries. This is fixed by implementing consistent retry counts and sleep times across all restore phases. (Bug #31372923)

• Backups errored out with FsErrInvalidParameters when the filesystem was running with O_DIRECT and a data file write was not aligned with the 512-byte block size used by O_DIRECT writes. If the total fragment size in the data file is not aligned with the O_DIRECT block size, NDB pads the last write to the required size, but when there were no fragments to write, BACKUP wrote only the header and footer to the data file. Since the header and footer are less than 512 bytes, leading to the issue with the O_DIRECT write.

  This is fixed by padding out the generic footer to 512 bytes if necessary, using an EMPTY_ENTRY, when closing the data file. (Bug #31180508)

• Altering the table comment of a fully replicated table using ALGORITHM=INPLACE led to an assertion. (Bug #31139313)

• Data nodes did not start when the RealtimeScheduler configuration parameter was set to 1. This was due to the fact that index builds during startup are performed by temporarily diverting some I/O threads for use as index building threads, and these threads inherited the realtime properties of the I/O threads. This caused a conflict (treated as a fatal error) when index build thread specifications were checked to ensure that they were not realtime threads. This is fixed by making sure that index build threads are not treated as realtime threads regardless of any settings applying to their host I/O threads, which is as actually intended in their design. (Bug #27533538)