MySQL Cluster 7.4.22 has been released

[Sreedhar Sreedhargadda]

Dear MySQL Users,

MySQL Cluster is the distributed, shared-nothing variant of MySQL.
This storage engine provides:

  - In-Memory storage - Real-time performance
  - Transparent Auto-Sharding - Read & write scalability
  - Active-Active/Multi-Master geographic replication
  - 99.999% High Availability with no single point of failure
    and on-line maintenance
  - NoSQL and SQL APIs (including C++, Java, http, Memcached
    and JavaScript/Node.js)

MySQL Cluster 7.4 makes significant advances in performance;
operational efficiency (such as enhanced reporting and faster restarts
and upgrades) and conflict detection and resolution for active-active
replication between MySQL Clusters.

MySQL Cluster 7.4.22, has been released and can be downloaded from

http://www.mysql.com/downloads/cluster/

where you will also find Quick Start guides to help you get your
first MySQL Cluster database up and running.

The release notes are available from

http://dev.mysql.com/doc/relnotes/mysql-cluster/7.4/en/index.html

MySQL Cluster enables users to meet the database challenges of next
generation web, cloud, and communications services with uncompromising
scalability, uptime and agility.

More details can be found at

http://www.mysql.com/products/cluster/

Enjoy !

==============================================================================
Changes in MySQL NDB Cluster 7.4.22 (5.6.42-ndb-7.4.22) (2018-10-23, General Availability)

   MySQL NDB Cluster 7.4.22 is a new release of MySQL NDB
   Cluster 7.4, based on MySQL Server 5.6 and including features
   in version 7.4 of the NDB storage engine, as well as fixing
   recently discovered bugs in previous NDB Cluster releases.

   Obtaining MySQL NDB Cluster 7.4.  MySQL NDB Cluster 7.4
   source code and binaries can be obtained from
https://dev.mysql.com/downloads/cluster/.

   For an overview of changes made in MySQL NDB Cluster 7.4, see
   What is New in NDB Cluster 7.4
   (http://dev.mysql.com/doc/refman/5.6/en/mysql-cluster-what-is-new-7-4.html).

   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 5.6
   through MySQL 5.6.42 (see Changes in MySQL 5.6.42 (Not yet
   released, General Availability)
   (http://dev.mysql.com/doc/relnotes/mysql/5.6/en/news-5-6-42.html)).

Bugs Fixed

     * MySQL NDB ClusterJ: When a table containing a BLOB or a
       TEXT field was being queried with ClusterJ for a record
       that did not exist, an exception ("The method is not
       valid in current blob state") was thrown. (Bug #28536926)

     * MySQL NDB ClusterJ: A NullPointerException was thrown
       when a full table scan was performed with ClusterJ on
       tables containing either a BLOB or a TEXT field. It was
       because the proper object initializations were omitted,
       and they have now been added by this fix. (Bug #28199372,
       Bug #91242)

     * When the SUMA kernel block receives a SUB_STOP_REQ
       signal, it executes the signal then replies with
       SUB_STOP_CONF. (After this response is relayed back to
       the API, the API is open to send more SUB_STOP_REQ
       signals.) After sending the SUB_STOP_CONF, SUMA drops the
       subscription if no subscribers are present, which
       involves sending multiple DROP_TRIG_IMPL_REQ messages to
       DBTUP. LocalProxy can handle up to 21 of these requests
       in parallel; any more than this are queued in the Short
       Time Queue. When execution of a DROP_TRIG_IMPL_REQ was
       delayed, there was a chance for the queue to become
       overloaded, leading to a data node shutdown with Error in
       short time queue.
       This issue is fixed by delaying the execution of the
       SUB_STOP_REQ signal if DBTUP is already handling
       DROP_TRIG_IMPL_REQ signals at full capacity, rather than
       queueing up the DROP_TRIG_IMPL_REQ signals. (Bug
       #26574003)

     * Having a large number of deferred triggers could
       sometimes lead to job buffer exhaustion. This could occur
       due to the fact that a single trigger can execute many
       operations---for example, a foreign key parent trigger
       may perform operations on multiple matching child table
       rows---and that a row operation on a base table can
       execute multiple triggers. In such cases, row operations
       are executed in batches. When execution of many triggers
       was deferred---meaning that all deferred triggers are
       executed at pre-commit---the resulting concurrent
       execution of a great many trigger operations could cause
       the data node job buffer or send buffer to be exhausted,
       leading to failure of the node.
       This issue is fixed by limiting the number of concurrent
       trigger operations as well as the number of trigger fire
       requests outstanding per transaction.
       For immediate triggers, limiting of concurrent trigger
       operations may increase the number of triggers waiting to
       be executed, exhausting the trigger record pool and
       resulting in the error Too many concurrently fired
       triggers (increase MaxNoOfFiredTriggers. This can be
       avoided by increasing MaxNoOfFiredTriggers, reducing the
       user transaction batch size, or both. (Bug #22529864)
       References: See also: Bug #18229003, Bug #27310330.

On Behalf of MySQL Release Engineering team,
-Sreedhar S