MySQL NDB Cluster 7.6.14 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 5.7.30 (see Changes in MySQL 5.7.30 (2020-04-27, General Availability)).
NDB Client Programs: Two options are added for the ndb_blob_tool utility, to enable it to detect missing blob parts for which inline parts exist, and to replace these with placeholder blob parts (consisting of space characters) of the correct length. To check whether there are missing blob parts, use the ndb_blob_tool
--check-missingoption. To replace with placeholders any blob parts which are missing, use the program's
--add-missingoption, also added in this release. (Bug #28583971)
NDB Client Programs: Removed a dependency from the ndb_waiter and ndb_show_tables utility programs on the
NDBTlibrary. This library, used in
NDBdevelopment for testing, is not required for normal use. The visible effect for users from this change is that these programs no longer print
NDBT_ProgramExit -following completion of a run. Applications that depend upon this behavior should be updated to reflect this change when upgrading to this release.
MySQL NDB ClusterJ: The unused
antlr3plugin has been removed from the ClusterJ
pomfile. (Bug #29931625)
MySQL NDB ClusterJ: The minimum Java version ClusterJ supports for MySQL NDB Cluster 8.0 is now Java 8. (Bug #29931625)
MySQL NDB ClusterJ: A few Java APIs used by ClusterJ are now deprecated in recent Java versions. These adjustments have been made to ClusterJ:
Class.getDeclaredConstructor().newInstance()calls. Also updated the exception handling and the test cases wherever required.
Numberclasses' constructors that instantiate an object from a
Stringor a primitive type are deprecated. Replaced all such deprecated instantiation calls with the corresponding
Proxy.getProxyClass()is now deprecated. The
DomainTypeHandlerImplclass now directly creates a new instance using the
Proxy.newProxyInstance()method; all references to the
Proxyclass and its constructors are removed from the
SessionFactoryImplclass now uses the interfaces underlying the proxy object to identify the domain class rather than using the Proxy class. Also updated
finalize()method is now deprecated. This patch does not change the overriding finalize() methods, but just suppresses the warnings on them. This deprecation will be handled separately in a later patch.
Updated the CMake configuration to treat deprecation warnings as errors when compiling ClusterJ.
It now possible to consolidate data from separate instances of NDB Cluster into a single target NDB Cluster when the original datasets all use the same schema. This is supported when using backups created using
START BACKUPin ndb_mgm and restoring them with ndb_restore, using the
--remap-columnoption implemented in this release (along with
--restore-dataand possibly other options).
--remap-columncan be employed to handle cases of overlapping primary, unique, or both sorts of key values between source clusters, and you need to make sure that they do not overlap in the target cluster. This can also be done to preserve other relationships between tables.
When used together with
--restore-data, the new option applies a function to the value of the indicated column. The value set for this option is a string of the format
, whose components are listed here:
db: Database name, after performing any renames.
tbl: Table name.
fn: Function name; currently, the only supported name is
args: The size of the offset to be added to the column value by
offset. The range of the argument is that of the signed variant of the column's type; thus, negative offsets are supported.
You can use
--remap-columnfor updating multiple columns of the same table and different columns of different tables, as well as combinations of multiple tables and columns. Different offset values can be employed for different columns of the same table.
As part of this work, two new options are also added to ndb_desc in this release:
ndb_restore now supports different primary key definitions for source and target tables when restoring from an
NDBnative backup, using the
--allow-pk-changesoption introduced in this release. Both increasing and decreasing the number of columns making up the original primary key are supported. This may be useful when it is necessary to accommodate schema version changes while restoring data, or when doing so is more efficient or less time-consuming than performing
ALTER TABLEstatements involving primary key changes on a great many tables following the restore operation.
When extending a primary key with additional columns, any columns added must not be nullable, and any values stored in any such columns must not change while the backup is being taken. Changes in the values of any such column while trying to add it to the table's primary key causes the restore operation to fail. Due to the fact that some applications set the values of all columns when updating a row even if the values of one or more of the columns does not change, it is possible to override this behavior by using the
--ignore-extended-pk-updatesoption which is also added in this release. If you do this, care must be taken to insure that such column values do not actually change.
When removing columns from the table's primary key, it is not necessary that the columns dropped from the primary key remain part of the table afterwards.
References: See also: Bug #30383919.
MySQL NDB ClusterJ: When a
Datevalue was read from a NDB cluster, ClusterJ sometimes extracted the wrong year value from the row. It was because the
Utilityclass, when unpacking the
Datevalue, wrongly extracted some extra bits for the year. This patch makes ClusterJ only extract the required bits. (Bug #30600320)
MySQL NDB ClusterJ: When the cluster's
NdbOperation::AbortOptiontype had the value of
AO_IgnoreOnError, when there was a read error, ClusterJ took that as the row was missing and returned
nullinstead of an exception. This was because with
execute()method always returns a success code after each transaction, and ClusterJ is supposed to check for any errors in any of the individual operations; however, read operations were not checked by ClusterJ in the case. With this patch, read operations are now checked for errors after query executions, so that a reading error is reported as such. (Bug #30076276)
When restoring signed auto-increment columns, ndb_restore incorrectly handled negative values when determining the maximum value included in the data. (Bug #30928710)
When a node ID allocation request failed with NotMaster temporary errors, the node ID allocation was always retried immediately, without regard to the cause of the error. This caused a very high rate of retries, whose effects could be observed as an excessive number of Alloc node id for node
nnnfailed log messages (on the order of 15,000 messages per second). (Bug #30293495)
NDBtables having no explicit primary key,
NdbReceiverBuffercould be allocated with too small a size. This was due to the fact that the attribute bitmap sent to
NDBfrom the data nodes always includes the primary key. The extra space required for hidden primary keys is now taken into consideration in such cases. (Bug #30183466)