Changes in MySQL NDB Cluster 7.6.20 (5.7.36-ndb-7.6.20) (2021-10-20, General Availability)

MySQL NDB Cluster 7.6.20 is a new release of NDB 7.6, based on MySQL Server 5.7 and including features in version 7.6 of the NDB storage engine, as well as fixing recently discovered bugs in previous NDB Cluster releases.

Obtaining NDB Cluster 7.6.  NDB Cluster 7.6 source code and binaries can be obtained from https://dev.mysql.com/downloads/cluster/.

For an overview of changes made in NDB Cluster 7.6, see What is New in NDB Cluster 7.6.

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 5.7 through MySQL 5.7.36 (see Changes in MySQL 5.7.36 (2021-10-19, General Availability)).

Bugs Fixed

• A buffer used in the SUMA kernel block did not always accommodate multiple signals. (Bug #33246047)

• It was possible in certain cases for an array index to exceed NO_OF_BUCKETS. (Bug #33019959)

• Added an ndbrequire() in QMGR to check whether the node ID received from the CM_REGREF signal is less than MAX_NDB_NODES. (Bug #32983311)

• A check was reported missing from the code for handling GET_TABLEID_REQ signals. To fix this issue, all code relating to all GET_TABLEID_* signals has been removed from the NDB sources, since these signals are no longer used or supported in NDB Cluster. (Bug #32983249)

• Added an ndbrequire() in QMGR to ensure that process reports from signal data use appropriate node IDs. (Bug #32983240)

• It was possible in some cases to specify an invalid node type when working with the internal management API. Now the API specifically disallows invalid node types, and defines an “unknown” node type (NDB_MGM_NODE_TYPE_UNKNOWN) to cover such cases. (Bug #32957364)

• ndb_restore raised a warning to use --disable-indexes when restoring data after the metadata had already been restored with --disable-indexes.

  When --disable-indexes is used to restore metadata before restoring data, the tables in the target schema have no indexes. We now check when restoring data with this option to ensure that there are no indexes on the target table, and print the warning only if the table already has indexes. (Bug #28749799)

• When restoring of metadata was done using --disable-indexes, there was no attempt to create indexes or foreign keys dependent on these indexes, but when ndb_restore was used without the option, indexes and foreign keys were created. When --disable-indexes was used later while restoring data, NDB attempted to drop any indexes created in the previous step, but ignored the failure of a drop index operation due to a dependency on the index of a foreign key which had not been dropped. This led subsequently to problems while rebuilding indexes, when there was an attempt to create foreign keys which already existed.

  We fix ndb_restore as follows:

  • When --disable-indexes is used, ndb_restore now drops any foreign keys restored from the backup.

  • ndb_restore now checks for the existence of indexes before attempting to drop them.

  (Bug #26974491)

• Event buffer status messages shown by the event logger have been improved. Percentages are now displayed only when it makes to do so. In addition, if a maximum size is not defined, the printout shows max=unlimited. (Bug #21276857)