MySQL Enterprise Monitor 8.0.24 Manual

Appendix C MySQL Enterprise Monitor Frequently Asked Questions


MySQL Enterprise Monitor is available as part of the MySQL Enterprise subscription, learn more at

FAQ Categories



Questions and Answers

C.1: If I upgrade to 3.1, what happens to the users defined in earlier versions?

All users defined in earlier versions are mapped to the default roles introduced in Access Control Lists in MySQL Enterprise Monitor 3.1. The user names are retained but their permissions are defined separately in default roles. All pre-existing users are automatically mapped to the default roles.

For example, if User1 is defined as a dba in MySQL Enterprise Monitor 3.0.x, User1 is created in MySQL Enterprise Monitor 3.1, but assigned to the dba Role. If User1 is defined as a dba, and granted both Query Analyzer permissions in 3.0.x, it is assigned to the default dba Role, and both Query Analyzer roles in 3.1.

General Usage


Questions and Answers

C.1: How do I find Ignored MySQL Instances? And how to I show them again?

From the MySQL Instances page, open the Unmonitored Instances panel and enable the Ignored Instance filter parameter and execute the search. This lists the ignored MySQL Instances.

To change the status of an ignored MySQL Instance, choose Show Instance from the context-menu for a specific MySQL Instance, or check the ignored MySQL Instance(s) and click the Show Instances button.

C.2: Using MySQL Enterprise Service Manager 3.2 with older agents, why am I seeing warning messages like the following in the agent logs?

WARN [HttpPollingJobFetcher-thread-0:com.mysql.etools.agent.ManagedOrder] 
bean order property CoalescedCollectionRunner.collections is a collection 
and contains a class not available on the agent. This element of the collection 
will be ignored. Upgrading the agent to a version at least the same as the service 
manager may solve this problem. 
java.lang.RuntimeException: java.lang.ClassNotFoundException: 

MySQL Enterprise Monitor 3.2 introduced support for multi-source replication. Some of the functionality introduced in the 3.2 agents is not available in the earlier agents. XXXXXXX represents one of the classes unavailable in the earlier agent.

These warnings do not imply anything is wrong with your installation or any data is missing from the collections. However, it is strongly recommended that you upgrade your agents to the same version as your MySQL Enterprise Service Manager.

C.3: In 2.3, the agent-mgmt-hostname contained the string "heartbeat" as the URLs path. Did this change?

Yes, this is no longer required and is ignored as of MySQL Enterprise Monitor 3.0.0.

C.4: How do I change the name of a server?

Open the MySQL Instances dashboard, and choose Edit Instance from the instance menu. Alternatively, toggle the checkbox for one instance and click Edit Instances.

Renaming the server in this way will override all other server naming, including changes to the agent configuration.

C.5: Does Query Analyzer work with all versions of MySQL and the MySQL Client Libraries?

MySQL 5.1 or later is supported.

Analyzing Performance Schema results requires MySQL Server 5.6.14 and above.

C.6: Why does the file apache-tomcat/logs/tomcat.log show error messages saying This is very likely to create a memory leak.? Is that anything to be concerned about?

This message is sometimes produced by underlying components of the web stack on web application reload or shutdown, and is not a cause for concern. It is not practical to shut off these spurious messages within Tomcat.

C.7: Why does monitoring a MySQL instance with FEDERATED tables cause extra connections, and decreased performance?

When the agent starts, it executes a discovery process that performs a number of INFORMATION_SCHEMA queries that gather table information for rules. These INFORMATION_SCHEMA queries can be costly on instances with many tables, particularly with large numbers of FEDERATED tables to another instance, as each table has a new session opened for it on the target machine.

MySQL Monitor


Questions and Answers

C.1: What are the features and related benefits of the MySQL Enterprise Monitor?

The MySQL Enterprise Monitor is like having a "Virtual DBA Assistant" at your side to recommend best practices to eliminate security vulnerabilities, improve replication, and optimize performance. For the complete features and benefits, visit the

C.2: What are the immediate benefits of implementing the MySQL Enterprise Monitor?

Often MySQL installations are implemented with default settings that may not be best suited for specific applications or usage patterns. The MySQL Advisors go to work immediately in these environments to identify potential problems and proactively notify and advise DBAs on key MySQL settings that can be tuned to improve availability, tighten security, and increase the throughput of their existing MySQL servers

C.3: What are the long-term benefits of the MySQL Enterprise Monitor?

Over time, the task of managing even medium-scale MySQL server farms becomes exponentially more complicated, especially as the load of users, connections, application queries, and objects on each MySQL server increases. The Enterprise Monitor continually monitors the dynamic security, performance, replication and schema relevant metrics of all MySQL servers, so as the number of MySQL continues to grow, DBAs are kept up to date on potential problems and proactive measures that can be implemented to ensure each server continues to operate at the highest levels of security, performance and reliability.

C.4: How is the MySQL Enterprise Monitor installed and deployed?

The Enterprise Monitor is powered by a distributed web application that is installed and deployed within the confines of the corporate firewall.

C.5: How is the Enterprise Monitor web application architected?

The Enterprise Monitor web application comprises three components:

C.6: What makes MySQL Enterprise unique?

Of the products on the market that monitor MySQL, SQL code and OS specific metrics, the MySQL Enterprise Monitor is the only solution that is built and supported by the engineers at MySQL. Unlike other solutions that report on raw MySQL and OS level metrics, the MySQL Enterprise Monitor is designed to optimize the use of MySQL by proactively monitoring MySQL instances and providing notifications and 'MySQL DBA expertise in a box' advice on corrective measures DBAs can take before problems occur.

C.7: What versions of MySQL are supported by the MySQL Enterprise Monitor?

The MySQL Enterprise Monitor supports MySQL versions 5.1 and above.

C.8: What operating system platforms are supported by the MySQL Enterprise Monitor?

The Enterprise Monitor Service Manager is fully supported on most current versions of Linux, Windows and Windows Server Editions, and Solaris. The Monitor Agent supports any platform supported by the MySQL Enterprise server. For the complete list of MySQL Enterprise supported operating systems and CPUs, visit MySQL Supported Platforms and select MySQL Enteprise Monitor.

C.9: How are subscribers notified about the availability of new or updated MySQL Enterprise Monitor, MySQL Enterprise Advisors and Advisor Rules?

Customers receive email notifications of new and updated MySQL Enterprise Monitor versions. Also, the What's New section of MySQL Enterprise Monitor, if enabled, contains new product announcements.

MySQL Query Analyzer


Questions and Answers

C.1: What is the MySQL Query Analyzer?

The MySQL Query Analyzer allows DBAs, developers and system administrators to improve application performance by collecting, monitoring, and analyzing queries as they run on their MySQL servers.

C.2: How is the MySQL Query Analyzer installed and enabled?

See Section 31.1, “Providing Query Analyzer Data”.

C.3: What overhead can I expect if the MySQL Query Analyzer is enabled?

Using MySQL 5.6, or higher, with Performance Schema enabled, there is no appreciable overhead.

C.4: What are the main features and benefits of the MySQL Query Analyzer?

For the complete features and benefits, see MySQL Enterprise Monitor Features and Benefits.

C.5: What are the typical use cases of the MySQL Query Analyzer?

The typical use cases for developers, DBAs and system administrators are:

C.6: What makes the MySQL Query Analyzer unique?

Other products (free, open source and commercial) that provide MySQL query monitoring are dependent on the MySQL Slow Query Log being enabled and available for sampling. While this provides some time savings over the DBA collecting and parsing the Log, the Slow Query Log comes with overhead and does not capture sub millisecond executions. The log data also grows very large very quickly.

The MySQL Query Analyzer collects queries and execution statistics with no dependence on the SQL Query Log, it captures all SQL statements sent to the MySQL server and provides an aggregated view into the most expensive queries in number of executions and total execution time. It is also fully supported as part of the MySQL Enterprise subscription.

C.7: How can I get the MySQL Query Analyzer?

The MySQL Query Analyzer is built into the MySQL Enterprise Monitor.

To experience the MySQL Enterprise Monitor for 30 days, visit the

C.8: Does Query Analyzer work with MySQL Cluster?

Yes, providing that exact node is monitored with an agent and query analyzer has been enabled for that node. Note that you must be accessing your cluster data through a standard MySQL node for this to work.

C.9: Does Query Analyzer enable me to monitor the disk reads and writes during a query?

No, that information is not available to the query analyzer, but many Advisors and graphs do handle this information. An Agent monitors the host, which includes monitoring of the CPU, Disk, and Memory.

C.10: Does Query Analyzer handler prepared statements?

At this time, the query analyzer does not track server-side prepared statements. However the default configurations for most client-side libraries for MySQL don't use them, they emulate them client-side, and those will be tracked by the query analyzer.

C.11: Will the Query Analyzer work without any special setup?

With MySQL Server 5.6.14 and greater, Query Analyzer data is automatically (by default) collected and displayed using the Performance Schema Statement Digests MySQL Server feature. If you are monitoring an earlier MySQL Server version, then you can continue to use alternative methods of providing query data to the Query Analyzer.

For information about the different methods of retrieving query data, see Section 31.1, “Providing Query Analyzer Data”.