Dear MySQL Users,

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

  - In-Memory storage - Real-time performance (with optional
    checkpointing to disk)
  - 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 7.5.12, has been released and can be downloaded from

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

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

Enjoy !

Changes in MySQL NDB Cluster 7.5.12 (5.7.24-ndb-7.5.12) (2018-10-23,
General Availability)

   MySQL NDB Cluster 7.5.12 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

   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 5.7.24 (see Changes in MySQL 5.7.24 (2018-10-22,
   General Availability)

Bugs Fixed

     * Packaging: Expected NDB header files were in the devel
       RPM package instead of libndbclient-devel. (Bug #84580,
       Bug #26448330)

     * 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.

     * 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
       ( <> d-definition.html#ndbparam-ndbd-maxnooffiredtriggers <>),
       reducing the user transaction batch size, or both.
       References: See also: Bug #18229003, Bug #27310330.

     * When moving an OperationRec from the serial to the
       parallel queue, Dbacc::startNext() failed to update the
       Operationrec::OP_ACC_LOCK_MODE flag which is required to
       reflect the accumulated OP_LOCK_MODE of all previous
       operations in the parallel queue. This inconsistency in
       the ACC lock queues caused the scan lock takeover
       mechanism to fail, as it incorrectly concluded that a
       lock to take over was not held. The same failure caused
       an assert when aborting an operation that was a member of
       such an inconsistent parallel lock queue. (Bug #92100,
       Bug #28530928)

     * DBTUP sent the error Tuple corruption detected when a
       read operation attempted to read the value of a tuple
       inserted within the same transaction. (Bug #92009,

     * False constraint violation errors could occur when
       executing updates on self-referential foreign keys.
       (Bug#91965, Bug #28486390)
       References: See also: Bug #90644, Bug #27930382.

     * An NDB internal trigger definition could be dropped while
       pending instances of the trigger remained to be executed,
       by attempting to look up the definition for a trigger
       which had already been released. This caused
       unpredictable and thus unsafe behavior possibly leading
       to data node failure. The root cause of the issue lay in
       an invalid assumption in the code relating to determining
       whether a given trigger had been released; the issue is
       fixed by ensuring that the behavior of NDB, when a
       trigger definition is determined to have been released,
       is consistent, and that it meets expectations.
       (Bug#91894, Bug #28451957)

     * In certain cases, a cascade update trigger was fired
       repeatedly on the same record, which eventually consumed
       all available concurrent operations, leading to Error 233
       Out of operation records in transaction coordinator
       (increase MaxNoOfConcurrentOperations). If
       ( <> definition.html#ndbparam-ndbd-maxnoofconcurrentoperations <>)
       was set to a value sufficiently high to avoid this,
       the issue manifested as data nodes consuming very large
       amounts of CPU, very likely eventually leading to a
       timeout. (Bug #91472, Bug #28262259)

     * Inserting a row into an NDB
       table having a self-referencing foreign key that
       referenced a unique index on the table other than the
       primary key failed with ER_NO_REFERENCED_ROW_2
       ( <> rver.html#error_er_no_referenced_row_2 <>). This was due to
       the fact that NDB checked foreign key constraints before
       the unique index was updated, so that the constraint
       check was unable to use the index for locating the row.
       Now, in such cases, NDB waits until all unique index
       values have been updated before checking foreign key
       constraints on the inserted row. (Bug #90644,
       References: See also: Bug #91965, Bug #28486390.

On Behalf of Oracle/MySQL Release Engineering Team
Prashant Tekriwal

Reply via email to