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 7.5.8, 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.

MySQL Cluster 7.5 is also available from our repository for Linux
platforms, go here for details:

http://dev.mysql.com/downloads/repo/

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 7.5.8 (5.7.20-ndb-7.5.8) (2017-10-18,
General Availability)

MySQL NDB Cluster 7.5.8 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
http://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 bugfixes and changes made
in previous NDB Cluster releases, as well as all bugfixes and
feature changes which were added in mainline MySQL 5.7
through MySQL 5.7.20 (see Changes in MySQL 5.7.20 (Not yet
released, General Availability)
(http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-20.html)).

Bugs Fixed

* Replication: With GTIDs generated for incident log
events, MySQL error code 1590 (ER_SLAVE_INCIDENT) could
not be skipped using the --slave-skip-errors=1590 startup
option on a replication slave. (Bug #26266758)

* Errors in parsing NDB_TABLE modifiers could cause memory
leaks. (Bug #26724559)

* Added DUMP code 7027 to facilitate testing of issues
relating to local checkpoints. For more information, see
DUMP 7027
(http://dev.mysql.com/doc/ndb-internals/en/ndb-internals-dump-command-7027.html).
(Bug #26661468)

* A previous fix intended to improve logging of node
failure handling in the transaction coordinator included
logging of transactions that could occur in normal
operation, which made the resulting logs needlessly
verbose. Such normal transactions are no longer written
to the log in such cases. (Bug #26568782)
References: This issue is a regression of: Bug #26364729.

* Due to a configuration file error, CPU locking capability
was not available on builds for Linux platforms. (Bug
#26378589)

* Some DUMP codes used for the LGMAN kernel block were
incorrectly assigned numbers in the range used for codes
belonging to DBTUX. These have now been assigned symbolic
constants and numbers in the proper range (10001, 10002,
and 10003). (Bug #26365433)

* Node failure handling in the DBTC kernel block consists
of a number of tasks which execute concurrently, and all
of which must complete before TC node failure handling is
complete. This fix extends logging coverage to record
when each task completes, and which tasks remain,
includes the following improvements:

+ Handling interactions between GCP and node failure
handling interactions, in which TC takeover causes
GCP participant stall at the master TC to allow it
to extend the current GCI with any transactions that
were taken over; the stall can begin and end in
different GCP protocol states. Logging coverage is
extended to cover all scenarios. Debug logging is
now more consistent and understandable to users.

+ Logging done by the QMGR block as it monitors
duration of node failure handling duration is done
more frequently. A warning log is now generated
every 30 seconds (instead of 1 minute), and this now
includes DBDIH block debug information (formerly
this was written separately, and less often).

+ To reduce space used, DBTC instance number: is
shortened to DBTC number:.

+ A new error code is added to assist testing.
(Bug #26364729)

* Error 899 Rowid already allocated... was reported under
certain conditions involving high loads on a cluster
having 4 or more data nodes. This occurred when a row ID
was available at the primary but not available at the
backup; a transaction that seized the row ID at the
primary failed to seize it at the backup since the ID was
unavailable.
For multiple operations on the same tuple where the end
result of the transaction is that the tuple is deleted,
the last operation on that tuple is marked to deallocate
the row ID. The operation is marked by setting a flag
during the COMMIT phase. When processing a COMPLETE
operation, this flag is checked, and if set, the row ID
is deallocated.
When a transaction contained a READ-EX operation,
followed by a DELETE on the same tuple, some commits
could be made out of order. When another transaction was
running insert operations on the same table, the
following events occurred in the order listed:

1. DELETE committed on primary

2. READ-EX committed on primary, marked as deallocator
on primary

3. READ-EX completed on primary, row ID deallocated

4. Freed row ID on primary seized by INSERT operation

5. INSERT tries to seize row ID on backup, gets Error
899 because row ID has not yet been freed on backup

6. DELETE completed on backup, row ID deallocated
This problem is fixed by enforcing a constraint such that
the deallocator operation must be a write operation, so
that read operations are ignored while choosing the
deallocator and the last write operation. Since write
operations are completed first at the backup and then at
the primary, this ensures that the row ID cannot be freed
at the primary before it is freed at the backup. In
addition, since row ID deallocation is now performed on
the primary and on the backup by the same operation, the
time between deallocation on the backup and deallocation
on the primary is significantly shortened. (Bug
#25960230)
References: See also: Bug #85706, Bug #26040805.

* NDB Cluster did not compile successfully when the build
used WITH_UNIT_TESTS=OFF
(http://dev.mysql.com/doc/refman/5.7/en/source-configuration-options.html#option_cmake_with_unit_tests).
(Bug
#86881, Bug #26375985)

* A potential hundredfold signal fan-out when sending a
START_FRAG_REQ signal could lead to a node failure due to
a job buffer full error in start phase 5 while trying to
perform a local checkpoint during a restart. (Bug #86675,
Bug #26263397)
References: See also: Bug #26288247, Bug #26279522.

* Compilation of NDB Cluster failed when using
-DWITHOUT_SERVER=1
(http://dev.mysql.com/doc/refman/5.7/en/source-configuration-options.html#option_cmake_without_server)
to build only the client libraries. (Bug #85524, Bug #25741111)




--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql