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ndbinfo
MySQL Cluster Information DatabaseManaging a MySQL Cluster involves a number of tasks, the first of which is to configure and start MySQL Cluster. This is covered in Section 17.3, “MySQL Cluster Configuration”, and Section 17.4, “MySQL Cluster Programs”.
The next few sections cover the management of a running MySQL Cluster.
For information about security issues relating to management and deployment of a MySQL Cluster, see Section 17.5.11, “MySQL Cluster Security Issues”.
There are essentially two methods of actively managing a running
MySQL Cluster. The first of these is through the use of commands
entered into the management client whereby cluster status can be
checked, log levels changed, backups started and stopped, and nodes
stopped and started. The second method involves studying the
contents of the cluster log
ndb_
;
this is usually found in the management server's
node_id
_cluster.logDataDir
directory, but this
location can be overridden using the
LogDestination
option.
(Recall that node_id
represents the
unique identifier of the node whose activity is being logged.) The
cluster log contains event reports generated by
ndbd. It is also possible to send cluster log
entries to a Unix system log.
Some aspects of the cluster's operation can be also be monitored
from an SQL node using the
SHOW ENGINE NDB
STATUS
statement.
In MySQL Cluster NDB 7.1.1 and later, detailed information about
cluster operations is available in real time through an SQL
interface using the ndbinfo
database. For more information, see
Section 17.5.10, “The ndbinfo
MySQL Cluster Information Database”.
Beginning with MySQL Cluster NDB 7.0.22 and MySQL Cluster NDB
7.1.11, NDB statistics counters provide improved monitoring using
the mysql client. These counters, implemented in
the NDB kernel, relate to operations performed by or affecting
Ndb
objects, such as starting,
closing, and aborting transactions; primary key and unique key
operations; table, range, and pruned scans; blocked threads waiting
for various operations to complete; and data and events sent and
received by MySQL Cluster. The counters are incremented by the NDB
kernel whenever NDB API calls are made or data is sent to or
received by the data nodes.
mysqld exposes the NDB API statistics counters as
system status variables, which can be identified from the prefix
common to all of their names (Ndb_api_
). The
values of these variables can be read in the
mysql client from the output of a
SHOW STATUS
statement, or by querying
either the
SESSION_STATUS
table
or the GLOBAL_STATUS
table (in the INFORMATION_SCHEMA
database). By
comparing the values of the status variables before and after the
execution of an SQL statement that acts on
NDB
tables, you can observe the actions
taken on the NDB API level that correspond to this statement, which
can be beneficial for monitoring and performance tuning of MySQL
Cluster.
MySQL Enterprise Monitor can also be used to monitor MySQL Servers that are part of
a MySQL Cluster deployment. MySQL Enterprise Monitor 2.3, added a MySQL Cluster
advisor, including a set of graphs providing information on MySQL
Cluster resources, and defining rules for alerts on key information
from data nodes such as
DataMemory
usage. This
information is made available to MySQL Enterprise Monitor 2.3 or later by any MySQL
Server which is connected to the MySQL Cluster, using
ndbinfo
. The advisor could be run
against a single MySQL Server in the Cluster, or against a pair in
order to provide a higher level of availability for the monitoring
service. For more information, see the
MySQL Enterprise Monitor
2.3 Manual.
MySQL Cluster Manager provides an advanced command-line interface that simplifies many otherwise complex MySQL Cluster management tasks, such as starting, stopping, or restarting a MySQL Cluster with a large number of nodes. The MySQL Cluster Manager client also supports commands for getting and setting the values of most node configuration parameters as well as mysqld server options and variables relating to MySQL Cluster. MySQL Cluster Manager 1.1 provides support for adding data nodes online. See the MySQL Cluster Manager 1.1 User Manual, for more information.
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