MySQL Cluster 7.4.12 has been released

[Sreedhar S]

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 7.4.12, 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 Cluster NDB 7.4.12 (5.6.31-ndb-7.4.12) (2016-07-18)

   MySQL Cluster NDB 7.4.12 is a new release of MySQL 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 MySQL Cluster releases.

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

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

   This release also incorporates all bugfixes and changes made
   in previous MySQL Cluster releases, as well as all bugfixes
   and feature changes which were added in mainline MySQL 5.6
   through MySQL 5.6.31 (see Changes in MySQL 5.6.31
   (2016-06-02)
   (http://dev.mysql.com/doc/relnotes/mysql/5.6/en/news-5-6-31.h
   tml)).

   Functionality Added or Changed

     * ClusterJ: To make it easier for ClusterJ to handle fatal
       errors that require the SessionFactory to be closed, a
       new public method in the SessionFactory interface,
       getConnectionPoolSessionCounts()
       (http://dev.mysql.com/doc/ndbapi/en/mccj-clusterj-session
       factory.html#mccj-clusterj-sessionfactory-getconnectionpo
       olsessioncounts), has been created. When it returns zeros
       for all pooled connections, it means all sessions have
       been closed, at which point the SessionFactory can be
       closed and reopened. See Reconnecting to a MySQL Cluster
       (http://dev.mysql.com/doc/ndbapi/en/mccj-using-clusterj-s
       tart.html#mccj-using-clusterj-reconnect) for more detail.
       (Bug #22353594)

   Bugs Fixed

     * Incompatible Change: When the data nodes are only
       partially connected to the API nodes, a node used for a
       pushdown join may get its request from a transaction
       coordinator on a different node, without (yet) being
       connected to the API node itself. In such cases, the
       NodeInfo object for the requesting API node contained no
       valid info about the software version of the API node,
       which caused the DBSPJ block to assume (incorrectly) when
       aborting to assume that the API node used NDB version
       7.2.4 or earlier, requiring the use of a backward
       compatability mode to be used during query abort which
       sent a node failure error instead of the real error
       causing the abort.
       Now, whenever this situation occurs, it is assumed that,
       if the NDB software version is not yet available, the API
       node version is greater than 7.2.4. (Bug #23049170)

     * Although arguments to the DUMP command are 32-bit
       integers, ndb_mgmd used a buffer of only 10 bytes when
       processing them. (Bug #23708039)

     * During shutdown, the mysqld process could sometimes hang
       after logging NDB Util: Stop ... NDB Util: Wakeup. (Bug
       #23343739)
       References: See also: Bug #21098142.

     * During an online upgrade from a MySQL Cluster NDB 7.3
       release to an NDB 7.4 (or later) release, the failures of
       several data nodes running the lower version during local
       checkpoints (LCPs), and just prior to upgrading these
       nodes, led to additional node failures following the
       upgrade. This was due to lingering elements of the
       EMPTY_LCP protocol initiated by the older nodes as part
       of an LCP-plus-restart sequence, and which is no longer
       used in NDB 7.4 and later due to LCP optimizations
       implemented in those versions. (Bug #23129433)

     * Reserved send buffer for the loopback transporter,
       introduced in MySQL Cluster NDB 7.4.8 and used by API and
       management nodes for administrative signals, was
       calculated incorrectly. (Bug #23093656)
       References: This issue is a regression of: Bug #21664515.

     * During a node restart, re-creation of internal triggers
       used for verifying the referential integrity of foreign
       keys was not reliable, because it was possible that not
       all distributed TC and LDM instances agreed on all
       trigger identities. To fix this problem, an extra step is
       added to the node restart sequence, during which the
       trigger identities are determined by querying the current
       master node. (Bug #23068914)
       References: See also: Bug #23221573.

     * Following the forced shutdown of one of the 2 data nodes
       in a cluster where NoOfReplicas=2, the other data node
       shut down as well, due to arbitration failure. (Bug
       #23006431)

     * The ndbinfo.tc_time_track_stats table uses histogram
       buckets to give a sense of the distribution of latencies.
       The sizes of these buckets were also reported as
       HISTOGRAM BOUNDARY INFO messages during data node
       startup; this printout was redundant and so has been
       removed. (Bug #22819868)

     * A failure occurred in DBTUP in debug builds when
       variable-sized pages for a fragment totalled more than 4
       GB. (Bug #21313546)

     * mysqld did not shut down cleanly when executing
       ndb_index_stat. (Bug #21098142)
       References: See also: Bug #23343739.

     * DBDICT and GETTABINFOREQ queue debugging were enhanced as
       follows:

          + Monitoring by a data node of the progress of
            GETTABINFOREQ signals can be enabled by setting
            DictTrace >= 2.

          + Added the ApiVerbose configuration parameter, which
            enables NDB API debug logging for an API node where
            it is set greater than or equal to 2.

          + Added DUMP code 1229 which shows the current state
            of the GETTABINFOREQ queue. (See DUMP 1229
            (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-du
            mp-command-1229.html).)
       See also The DBDICT Block
       (http://dev.mysql.com/doc/ndbapi/en/ndb-internals-kernel-
       blocks-dbdict.html). (Bug #20368450)
       References: See also: Bug #20368354.

     * Cluster API: Deletion of Ndb objects used a
       dispoportionately high amount of CPU. (Bug #22986823)

On behalf of the MySQL Release Team
-Sree