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
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/7.5/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 7.5.12 (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
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster.html)
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
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-what-is-new-7-5.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 5.7
through MySQL 5.7.24 (see Changes in MySQL 5.7.24 (2018-10-22,
General Availability)
(http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-24.html)).
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
(http://dev.mysql.com/doc/refman/5.7/en/blob.html) or a
TEXT (http://dev.mysql.com/doc/refman/5.7/en/blob.html)
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
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndb
<http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndbd-definition.html#ndbparam-ndbd-maxnooffiredtriggers>
d-definition.html#ndbparam-ndbd-maxnooffiredtriggers
<http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndbd-definition.html#ndbparam-ndbd-maxnooffiredtriggers>),
reducing the user transaction batch size, or both.
(Bug#22529864)
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,
Bug#28500861)
* 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
MaxNoOfConcurrentOperations
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndbd-
<http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndbd-definition.html#ndbparam-ndbd-maxnoofconcurrentoperations>
definition.html#ndbparam-ndbd-maxnoofconcurrentoperations
<http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndbd-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
(http://dev.mysql.com/doc/refman/5.7/en/mysql-cluster.html)
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
(http://dev.mysql.com/doc/refman/5.7/en/error-messages-se
<http://dev.mysql.com/doc/refman/5.7/en/error-messages-server.html#error_er_no_referenced_row_2>
rver.html#error_er_no_referenced_row_2
<http://dev.mysql.com/doc/refman/5.7/en/error-messages-server.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,
Bug#27930382)
References: See also: Bug #91965, Bug #28486390.
On Behalf of Oracle/MySQL Release Engineering Team
Prashant Tekriwal