Changes in MySQL NDB Cluster 7.5.13 (5.7.25-ndb-7.5.13) (2019-01-22, General Availability)

MySQL NDB Cluster 7.5.13 is a new release of MySQL NDB Cluster 7.5, based on MySQL Server 5.7 and including features in version 7.5 of the NDB storage engine, as well as fixing recently discovered bugs in previous NDB Cluster releases.

Obtaining MySQL NDB Cluster 7.5.  MySQL NDB Cluster 7.5 source code and binaries can be obtained from https://dev.mysql.com/downloads/cluster/.

For an overview of changes made in MySQL NDB Cluster 7.5, see What is New in NDB Cluster 7.5.

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 5.7.25 (see Changes in MySQL 5.7.25 (2019-01-21, General Availability)).

Bugs Fixed

• Important Change: When restoring to a cluster using data node IDs different from those in the original cluster, ndb_restore tried to open files corresponding to node ID 0. To keep this from happening, the --nodeid and --backupid options—neither of which has a default value—are both now explicitly required when invoking ndb_restore. (Bug #28813708)

• Packaging; MySQL NDB ClusterJ: libndbclient was missing from builds on some platforms. (Bug #28997603)

• NDB Disk Data: When a log file group had more than 18 undo logs, it was not possible to restart the cluster. (Bug #251155785)

  References: See also: Bug #28922609.

• NDB Replication: When writes on the master—done in such a way that multiple changes affecting BLOB column values belonging to the same primary key were part of the same epoch—were replicated to the slave, Error 1022 occurred due to constraint violations in the NDB$BLOB_id_part table. (Bug #28746560)

• When a local checkpoint (LCP) was complete on all data nodes except one, and this node failed, NDB did not continue with the steps required to finish the LCP. This led to the following issues:

  No new LCPs could be started.

  Redo and Undo logs were not trimmed and so grew excessively large, causing an increase in times for recovery from disk. This led to write service failure, which eventually led to cluster shutdown when the head of the redo log met the tail. This placed a limit on cluster uptime.

  Node restarts were no longer possible, due to the fact that a data node restart requires that the node's state be made durable on disk before it can provide redundancy when joining the cluster. For a cluster with two data nodes and two fragment replicas, this meant that a restart of the entire cluster (system restart) was required to fix the issue (this was not necessary for a cluster with two fragment replicas and four or more data nodes). (Bug #28728485, Bug #28698831)

  References: See also: Bug #11757421.

• Running ANALYZE TABLE on an NDB table with an index having longer than the supported maximum length caused data nodes to fail. (Bug #28714864)

• It was possible in certain cases for nodes to hang during an initial restart. (Bug #28698831)

  References: See also: Bug #27622643.

• The output of ndb_config --configinfo --xml --query-all now shows that configuration changes for the ThreadConfig and MaxNoOfExecutionThreads data node parameters require system initial restarts (restart="system" initial="true"). (Bug #28494286)

• Executing SELECT * FROM INFORMATION_SCHEMA.TABLES caused SQL nodes to restart in some cases. (Bug #27613173)

• When tables with BLOB columns were dropped and then re-created with a different number of BLOB columns the event definitions for monitoring table changes could become inconsistent in certain error situations involving communication errors when the expected cleanup of the corresponding events was not performed. In particular, when the new versions of the tables had more BLOB columns than the original tables, some events could be missing. (Bug #27072756)

• When running a cluster with 4 or more data nodes under very high loads, data nodes could sometimes fail with Error 899 Rowid already allocated. (Bug #25960230)

• When starting, a data node copies metadata, while a local checkpoint updates metadata. To avoid any conflict, any ongoing LCP activity is paused while metadata is being copied. An issue arose when a local checkpoint was paused on a given node, and another node that was also restarting checked for a complete LCP on this node; the check actually caused the LCP to be completed before copying of metadata was complete and so ended the pause prematurely. Now in such cases, the LCP completion check waits to complete a paused LCP until copying of metadata is finished and the pause ends as expected, within the LCP in which it began. (Bug #24827685)

• Asynchronous disconnection of mysqld from the cluster caused any subsequent attempt to start an NDB API transaction to fail. If this occurred during a bulk delete operation, the SQL layer called HA::end_bulk_delete(), whose implementation by ha_ndbcluster assumed that a transaction had been started, and could fail if this was not the case. This problem is fixed by checking that the transaction pointer used by this method is set before referencing it. (Bug #20116393)

• NdbScanFilter did not always handle NULL according to the SQL standard, which could result in sending non-qualifying rows to be filtered (otherwise not necessary) by the MySQL server. (Bug #92407, Bug #28643463)

  References: See also: Bug #93977, Bug #29231709.

• NDB attempted to use condition pushdown on greater-than (>) and less-than (<) comparisons with ENUM column values but this could cause rows to be omitted in the result. Now such comparisons are no longer pushed down. Comparisons for equality (=) and inequality (<> / !=) with ENUM values are not affected by this change, and conditions including these comparisons can still be pushed down. (Bug #92321, Bug #28610217)