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This chapter contains information about
MySQL Cluster, which is a
high-availability, high-redundancy version of MySQL adapted for the
distributed computing environment. Recent releases of MySQL Cluster
use version 7 of the
engine (also known as
NDB) to enable
running several computers with MySQL servers and other software in a
cluster; the latest releases available for production use
NDB version 7.2.
Support for the
engine is not included in the standard MySQL Server 5.5 binaries
built by Oracle. Instead, users of MySQL Cluster binaries from
Oracle should upgrade to the most recent binary release of MySQL
Cluster for supported platforms—these include RPMs that should
work with most Linux distributions. MySQL Cluster users who build
from source should use the sources provided for MySQL Cluster.
(Locations where the sources can be obtained are listed later in
This chapter contains information about MySQL Cluster NDB 7.2 releases through 5.5.49-ndb-7.2.25. Currently, the MySQL Cluster NDB 7.3 and MySQL Cluster NDB 7.4 release series are both Generally Available (GA). MySQL Cluster NDB 7.2 is a previous GA release series; although this series is still supported, we recommend that new deployments use MySQL Cluster NDB 7.4. For information about MySQL Cluster NDB 7.4, see MySQL Cluster NDB 7.3 and MySQL Cluster NDB 7.4, in the MySQL 5.6 Manual. MySQL Cluster NDB 7.5 is also available as a Developer Preview; see MySQL Cluster NDB 7.5.
Release notes for the changes in each release of MySQL Cluster are located at MySQL Cluster 7.2 Release Notes.
Supported Platforms. MySQL Cluster is currently available and supported on a number of platforms. For exact levels of support available for on specific combinations of operating system versions, operating system distributions, and hardware platforms, please refer to http://www.mysql.com/support/supportedplatforms/cluster.html.
Availability. MySQL Cluster binary and source packages are available for supported platforms from http://dev.mysql.com/downloads/cluster/.
MySQL Cluster release numbers.
MySQL Cluster follows a somewhat different release pattern from
the mainline MySQL Server 5.5 series of releases. In this
Manual and other MySQL documentation, we
identify these and later MySQL Cluster releases employing a
version number that begins with “NDB”. This version
number is that of the
storage engine used in the release, and not of the MySQL server
version on which the MySQL Cluster release is based.
Version strings used in MySQL Cluster software. The version string displayed by MySQL Cluster programs uses this format:
mysql_server_version represents the
version of the MySQL Server on which the MySQL Cluster release is
based. For all MySQL Cluster NDB 6.x and 7.x releases, this is
the version of the
NDB storage engine
used by this release of the MySQL Cluster software. You can see this
format used in the mysql client, as shown here:
mysqlWelcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.5.49-ndb-7.2.25 Source distribution Type 'help;' or '\h' for help. Type '\c' to clear the buffer. mysql>
SELECT VERSION()\G*************************** 1. row *************************** VERSION(): 5.5.49-ndb-7.2.25 1 row in set (0.00 sec)
This version string is also displayed in the output of the
SHOW command in the ndb_mgm
SHOWConnected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=1 @10.0.10.6 (5.5.49-ndb-7.2.25, Nodegroup: 0, *) id=2 @10.0.10.8 (5.5.49-ndb-7.2.25, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=3 @10.0.10.2 (5.5.49-ndb-7.2.25) [mysqld(API)] 2 node(s) id=4 @10.0.10.10 (5.5.49-ndb-7.2.25) id=5 (not connected, accepting connect from any host)
The version string identifies the mainline MySQL version from which
the MySQL Cluster release was branched and the version of the
NDBCLUSTER storage engine used. For
example, the full version string for MySQL Cluster NDB 7.2.4 (the
first MySQL Cluster production release based on MySQL Server 5.5) is
mysql-5.5.19-ndb-7.2.4. From this we can
determine the following:
Since the portion of the version string preceding “
-ndb-” is the base MySQL Server version, this means that MySQL Cluster NDB 7.2.4 derives from the MySQL 5.5.19, and contains all feature enhancements and bugfixes from MySQL 5.5 up to and including MySQL 5.5.19.
Since the portion of the version string following “
-ndb-” represents the version number of the
NDBCLUSTER) storage engine, MySQL Cluster NDB 7.2.4 uses version 7.2.4 of the
New MySQL Cluster releases are numbered according to updates in the
NDB storage engine, and do not necessarily
correspond in a one-to-one fashion with mainline MySQL Server
releases. For example, MySQL Cluster NDB 7.2.4 (as previously noted)
is based on MySQL 5.5.19, while MySQL Cluster NDB 7.2.0 was based on
MySQL 5.1.51 (version string:
Compatibility with standard MySQL 5.5 releases.
While many standard MySQL schemas and applications can work using
MySQL Cluster, it is also true that unmodified applications and
database schemas may be slightly incompatible or have suboptimal
performance when run using MySQL Cluster (see
Section 18.1.6, “Known Limitations of MySQL Cluster”). Most of these issues
can be overcome, but this also means that you are very unlikely to
be able to switch an existing application datastore—that
currently uses, for example,
InnoDB—to use the
NDB storage engine without allowing
for the possibility of changes in schemas, queries, and
applications. In addition, the MySQL Server and MySQL Cluster
codebases diverge considerably, so that the standard
mysqld cannot function as a drop-in replacement
for the version of mysqld supplied with MySQL
MySQL Cluster development source trees. MySQL Cluster development trees can also be accessed from https://github.com/mysql/mysql-server.
The MySQL Cluster development sources maintained at https://github.com/mysql/mysql-server are licensed under the GPL. For information about obtaining MySQL sources using Bazaar and building them yourself, see Section 2.9.3, “Installing MySQL Using a Development Source Tree”.
As with MySQL Server 5.5, MySQL Cluster NDB 7.2 is built using CMake.
Currently, MySQL Cluster NDB 7.3 and MySQL Cluster NDB 7.4 releases are Generally Available (GA). We recommend that new deployments use MySQL Cluster NDB 7.4. MySQL Cluster NDB 7.1 and earlier versions are no longer in active development. For an overview of major features added in MySQL Cluster NDB 7.4, see What is New in MySQL Cluster NDB 7.4. For similar information about MySQL Cluster NDB 7.3, see What is New in MySQL Cluster NDB 7.3. For an overview of major features added in past MySQL Cluster releases, see MySQL Cluster Development History. MySQL Cluster NDB 7.5 is also available as a Developer Preview for testing of new features; for more information, see MySQL Cluster NDB 7.5.
This chapter represents a work in progress, and its contents are subject to revision as MySQL Cluster continues to evolve. Additional information regarding MySQL Cluster can be found on the MySQL Web site at http://www.mysql.com/products/cluster/.
Additional Resources. More information about MySQL Cluster can be found in the following places:
For answers to some commonly asked questions about MySQL Cluster, see Section A.10, “MySQL FAQ: MySQL 5.5 and MySQL Cluster”.
The MySQL Cluster mailing list: http://lists.mysql.com/cluster.
The MySQL Cluster Forum: http://forums.mysql.com/list.php?25.
Many MySQL Cluster users and developers blog about their experiences with MySQL Cluster, and make feeds of these available through PlanetMySQL.