Added the DictTrace data node configuration parameter, for use in debugging NDB code. For more information, see Defining MySQL Cluster Data Nodes. (Bug #55963)

Important Change; Cluster API: The poll and select calls made by the MGM API were not interrupt-safe; that is, a signal caught by the process while waiting for an event on one or more sockets returned error -1 with errno set to EINTR. This caused problems with MGM API functions such as ndb_logevent_get_next() and ndb_mgm_get_status2().

To fix this problem, the internal ndb_socket_poller::poll() function has been made EINTR-safe.

The old version of this function has been retained as poll_unsafe(), for use by those parts of NDB that do not need the EINTR-safe version of the function. (Bug #55906)

When another data node failed, a given data node DBTC kernel block could time out while waiting for DBDIH to signal commits of pending transactions, leading to a crash. Now in such cases the timeout generates a prinout, and the data node continues to operate. (Bug #55715)

An excessive number of timeout warnings (normally used only for debugging) were written to the data node logs. (Bug #53987)

It was possible for a DROP DATABASE statement to remove NDB hidden blob tables without removing the parent tables, with the result that the tables, although hidden to MySQL clients, were still visible in the output of ndb_show_tables but could not be dropped using ndb_drop_table. (Bug #54788)

The configure.js option WITHOUT_DYNAMIC_PLUGINS=TRUE was ignored when building MySQL Cluster for Windows using CMake. Among the effects of this issue was that CMake attempted to build the InnoDB storage engine as a plugin (.DLL file) even though the InnoDB Plugin is not currently supported by MySQL Cluster. (Bug #54913)

Disk Data: As an optimization when inserting a row to an empty page, the page is not read, but rather simply initialized. However, this optimzation was performed in all cases when an empty row was inserted, even though it should have been done only if it was the first time that the page had been used by a table or fragment. This is because, if the page had been in use, and then all records had been released from it, the page still needed to be read to learn its log sequence number (LSN).

This caused problems only if the page had been flushed using an incorrect LSN and the data node failed before any local checkpoint was completed—which would remove any need to apply the undo log, hence the incorrect LSN was ignored.

The user-visible result of the incorrect LSN was that it caused the data node to fail during a restart. It was perhaps also possible (although not conclusively proven) that this issue could lead to incorrect data. (Bug #54986)

Cluster Replication: When inserting rows into the mysql.ndb_binlog_index table, duplicate key errors occurred when the size of the epoch number (a 64-bit integer) exceeded 2⁵³. This happened because the NDB storage engine handler called the wrong overloaded variant of a MySQL Server internal API (the Field::store() method), which resulted in the epoch being mapped to a 64-bit double precision floating point number and a corresponding loss of accuracy for numbers greater than 2⁵³. (Bug #35217)

Cluster API: Calling NdbTransaction::refresh() did not update the timer for TransactionInactiveTimeout. (Bug #54724)