Archive for November 17, 2010

MySQL Cluster 7.1.9 binaries released

The binary version for MySQL Cluster 7.1.9 has now been made available at

A description of all of the changes (fixes) that have gone into MySQL Cluster 7.1.9 (compared to 7.1.8) can be found in the official MySQL Cluster documentation. In addition, there is a great BLOG posting from Johan Anderson explaining how to use the new table added to ndbinfo to tune DiskPageBufferMemory when storing tables on disk.

MySQL Cluster 6.3.39 binaries released

The binary version for MySQL Cluster 6.3.39 has now been made available at

A description of all of the changes (fixes) that have gone into MySQL Cluster 6.3.39 (compared to 6.3.38) can be found in the official MySQL Cluster documentation.

MySQL (including Cluster) at the 2010 UK Oracle User Group Conference

The UK Oracle User Group Conference runs from 29th November through 1st December 2010 – the MySQL content is on Wednesday 1st at the ICC in Birmingham. This is a great chance for MySQL users to find out more on the latest developments and question some of the experts (both from inside and outside Oracle) and for Oracle users who don’t have experience with MySQL to discover what it’s all about.

The day starts with a keynote from Rich Mason (VP responsible for MySQL sales) at 8:45; I’ll be part of a MySQL panel at 9:50 and then Mat Keep and I will be presenting on MySQL Cluster at 14:15. In the Cluster session we’ll will introduce MySQL Cluster and cover the most important features of MySQL Cluster 7.1: ndbinfo; MySQL Cluster Connector/Java and other features that push the limits of MySQL Cluster into new workloads and communities.

ndbinfo presents real-time usage statistics from the MySQL Cluster data nodes as a series of SQL tables, enabling developers and administrators to monitor database performance and optimize their applications.

Designed for Java developers, the MySQL Cluster Connector for Java implements an easy-to-use and high performance native Java interface and OpenJPA plug-in that maps Java classes to tables stored in the MySQL Cluster database.

Finally, we’ll present some real-world case studies and explain some of the new capabilities that are currently in development.

Another session that’s likely to be suited to people interested in MySQL Cluster is a more general presentation on delivering High Availability with MySQL – presented by Mario Beck.

As you’d expect there are many more MySQL sessions to choose from – check the full schedule.

To register for just the MySQL sessions use the MySQL registration page, the full conference registration page is here.

Hope to see as many of you there as possible!

Monitoring MySQL Cluster with MySQL Enterprise Monitor

MySQL Enterprise Monitor with MySQL Cluster

A few months ago, I posted a walkthrough of how to extend MySQL Enterprise Monitor in order to monitor MySQL Cluster. The great news is that as of MySQL Enterprise Monitor 2.3 (available from Oracle E-Delivery since 1st November) this functionality is included in the core product and so there is no need to add the extra features in manually. Of course, that post might still be of interest if you want to further extend MySQL Enterprise Monitor.

This post briefly steps through the new (Cluster-specific) functionality but if you’re interested, why not try it for yourself and download the new MySQL Enterprise Monitor software from Oracle E-Delivery. If you like what you see then the good news is that if you take out a subscription for MySQL Cluster CGE (or buy a license) then this now also entitles you to use MySQL Enterprise Monitor.

There are two main aspects that have been extended to cover MySQL Cluster:

  • A new MySQL Cluster Advisor has been added. This Advisor is made up of a set of rules that check various aspects of the data nodes and raise alerts if a configurable threshold is exceeded
  • A set of new graphs have been added so that you can monitor the usage of key resources over time.

Note that MySQL Enterprise Monitor has no direct connection to the data nodes and so one or more of the MySQL Servers from the Cluster is effectively used as a proxy. There is nothing special for you to configure on the servers, behind the scenes, Enterprise Monitor is reading the contents of the ndbinfo database that was introduced in MySQL Cluster 7.1.

If using an older version of MySQL Cluster then you get less benefit from MySQL Enterprise Monitor but there is still some value in using it to monitor the MySQL Servers that are part of the cluster:

  • Use the Query Analyzer to keep track of how your applications access the database and troubleshoot performance issues
  • Monitor the state of the MySQL Server itself (number of client connections, CPU usage etc.)
  • Generate alerts when data nodes are out of service.

Schedule Cluster Rules Against the Servers

There is documentation covering installing and running the MySQL Enterprise Monitor service manager and agents and so I won’t repeat the steps here except to point out that you need one or more of the agents to be configured to monitor one or more of the MySQL Servers in your Cluster. Of course, you could monitor multiple MySQL Cluster deployments from the same dashboard – just make sure that you have an agent monitoring at least one MySQL Server from each one.

By default, none of the rules from the MySQL Cluster Advisor are scheduled against any of your servers and so the first thing you need to do is go to the “Advisors” tab and from their select “Add to Schedule”. Select the server(s) on the left and then check the radio button(s) against the whole Cluster advisor or against one or more of the rules within it and click the “schedule” button. You’ll then be given the option to override the default frequency that each rule is run before confirming the activation (scheduling) of the rule(s) for your server(s). This is also the point where you can indicate whether or not an SNMP Trap should be raised when the alert is raised/cleared (the destinations for the SNMP notifications can be set under the “Settings” tab).

Error scheduling rules against wrong version of MySQL Server

Note that if you try scheduling the Cluster Advisor rules against a MySQL Server that is not part of a MySQL Cluster 7.1 (or later) deployment they you will get errors indicating that the server cannot provide the required data.








MySQL Cluster Graphs

The new MySQL Cluster graphs are activated by default and you can view them from the “Graphs” tab but note that if there are no MySQL Cluster 7.1 servers in the list that you highlight on the left of the browser then the Cluster graphs will be hidden.






Customize Cluster Rule

Note that there is still scope for simple customizations directly from the the MySQL Enterprise Monitor GUI. For example if you don’t think that the default thresholds are appropriate for your configuration then select “Manage Rules” within the “Advisors” tab and then click “edit” next to the rule in question – you then get the option to alter the threshold values.

As a final configuration step, go back to the “Monitor” tab and click on “edit favorites” to promote your favourite Cluster graphs to the home screen.


Details of Cluster alert

Any Critical alerts (including ones for the newly scheduled Cluster rules) will appear on the Monitor page – to see the Info and Warning alerts, select the “Events” tab. Clicking on any of these alerts will give you extra details and the opportunity to close the alert.

MySQL Cluster Manager 1.1 available!

As the title of this post suggests, MySQL Cluster Manager 1.1 is now available – but this actually has a double meaning:

  1. MySQL Cluster Manager 1.1 is GA (I’ll explain below the major improvements over 1.0)
  2. Everyone is now able to download and try it (without first having to purchase a license)!

This software is only available through commercial licenses (i.e. not GPL like the rest of Cluster) and until recently there was no way for anyone to try it out unless they had already bought MySQL Cluster CGE; this changed on Monday when the MySQL software became available through Oracle’s E-Delivery site. Now you can download the software and try it out for yourselves (just select “MySQL Database” as the product pack, select your platform, click “Go” and then scroll down to get the software).

So What is MySQL Cluster Manager?

MySQL Cluster Manager provides the ability to control the entire cluster as a single entity, while also supporting very granular control down to individual processes within the cluster itself.  Administrators are able to create and delete entire clusters, and to start, stop and restart the cluster with a single command.  As a result, administrators no longer need to manually restart each data node in turn, in the correct sequence, or to create custom scripts to automate the process.

MySQL Cluster Manager automates on-line management operations, including the upgrade, downgrade and reconfiguration of running clusters as well as adding nodes on-line for dynamic, on-demand scalability, without interrupting applications or clients accessing the database.  Administrators no longer need to manually edit configuration files and distribute them to other cluster nodes, or to determine if rolling restarts are required. MySQL Cluster Manager handles all of these tasks, thereby enforcing best practices and making on-line operations significantly simpler, faster and less error-prone.

MySQL Cluster Manager is able to monitor cluster health at both an Operating System and per-process level by automatically polling each node in the cluster.  It can detect if a process or server host is alive, dead or has hung, allowing for faster problem detection, resolution and recovery.

To deliver 99.999% availability, MySQL Cluster has the capability to self-heal from failures by automatically restarting failed Data Nodes, without manual intervention.  MySQL Cluster Manager extends this functionality by also monitoring and automatically recovering SQL and Management Nodes.  

How is it Implemented?

MySQL Cluster Manager Architecture

MySQL Cluster Manager is implemented as a series of agent processes that co-operate with each other to manage the MySQL Cluster deployment; one agent running on each host machine that will be running a MySQL Cluster node (process). The administrator uses the regular mysql command to connect to any one of the agents using the port number of the agent (defaults to 1862 compared to the MySQL Server default of 3306).

How is it Used?

When using MySQL Cluster Manager to manage your MySQL Cluster deployment, the administrator no longer edits the configuration files (for example config.ini and my.cnf); instead, these files are created and maintained by the agents. In fact, if those files are manually edited, the changes will be overwritten by the configuration information which is held within the agents. Each agent stores all of the cluster configuration data, but it only creates the configuration files that are required for the nodes that are configured to run on that host.

Similarly when using MySQL Cluster Manager, management actions must not be performed by the administrator using the ndb_mgm command (which directly connects to the management node meaning that the agents themselves would not have visibility of any operations performed with it).

When using MySQL Cluster Manager, the ‘angel’ processes are no longer needed (or created) for the data nodes, as it becomes the responsibility of the agents to detect the failure of the data nodes and recreate them as required. Additionally, the agents extend this functionality to include the management nodes and MySQL Server nodes.

Example 1: Create a Cluster from Scratch

The first step is to connect to one of the agents and then define the set of hosts that will be used for the Cluster:

$ mysql -h -P 1862 -u admin -psuper --prompt='mcm> '
mcm> create site --hosts=,,, mysite;

Next step is to tell the agents where they can find the Cluster binaries that are going to be used, define what the Cluster will look like (which nodes/processes will run on which hosts) and then start the Cluster:

mcm> add package --basedir=/usr/local/mysql_6_3_27a 6.3.27a;
mcm> create cluster --package=6.3.26
ndbd@,mysqld@,mysqld@ mycluster;
mcm> start cluster mycluster; 

Example 2: On-Line upgrade of a Cluster

A great example of how MySQL Cluster Manager can simplify management operations is upgrading the Cluster software. If performing the upgrade by hand then there are dozens of steps to run through which is time consuming, tedious and subject to human error (for example, restarting nodes in the wrong order could result in an outage). With MySQL Cluster Manager, it is reduced to two commands – define where to find the new version of the software and then perform the rolling, in-service upgrade:

mcm> add package --basedir=/usr/local/mysql_7_1_8 7.1.8;
mcm> upgrade cluster --package=7.1.8 mycluster;

Behind the scenes, each node will be halted and then restarted with the new version – ensuring that there is no loss of service.

What’s New in MySQL Cluster Manager 1.1

If you’ve previously tried out version 1.0 then the main improvements you’ll see in 1.1 are:

  • More robust; 1.0 was the first release and a lot of bug fixes have gone in since then
  • Optimized restarts – more selective about which nodes need to be restarted when making a configuration change
  • Automated On-line Add-node

MySQL Cluster Manager 1.1 – Automated On-Line Add-Node

Automated On-Line Add-Node

Since MySQL Cluster 7.0 it has been possible to add new nodes to a Cluster while it is still in service; there are a number of steps involved and as with on-line upgrades if the administrator makes a mistake then it could lead to an outage.

We’ll now look at how this is automated when using MySQL Cluster Manager; the first step is to add any new hosts (servers) to the site and indicate where those hosts can find the Cluster software:

mcm> add hosts --hosts=, mysite;
mcm> add package --basedir=/usr/local/mysql_7_1_8 --hosts=, 7_1_8;

The new nodes can then be added to the Cluster and then started up:

mcm> add process --processhosts=mysqld@,mysqld@,ndbd@,
ndbd@,ndbd@,ndbd@ mycluster;
mcm> start process --added mycluster; 

The Cluster has now been extended but you need to perform a final step from any of the MySQL Servers to repartition the existing Cluster tables to use the new data nodes:

mysql> OPTIMIZE TABLE <table-name>;

Where can I found out more?

There is a lot of extra information to help you understand what can be achieved with MySQL Cluster Manager and how to use it: