Appendix A MySQL Enterprise Monitor Frequently Asked Questions


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

FAQ Categories

General Usage


Questions and Answers

A.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.

A.2: 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.

A.3: 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.

A.4: 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.

A.5: Why do some rules appear to have a Severity of Unknown?

Due to timing issues, certain rules such as 32-Bit Binary Running on 64-Bit AMD Or Intel System and Key Buffer Size Greater Than 4 GB do not evaluate correctly due to timing issues. This is a known issue that is expected to be resolved in future versions of MySQL Enterprise Monitor.

A.6: Can I run MySQL Enterprise Service Manager on machine with other applications running?

You can, but Oracle recommends running your MySQL Enterprise Service Manager on a dedicated machine, especially when monitoring many agents.

A.7: 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.

A.8: 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

A.1: What is MySQL Enterprise Monitor?

Included as part of a MySQL Enterprise subscription, the MySQL Enterprise Monitor is a distributed, web-based application that helps customers reduce downtime, tighten security and increase throughput of their MySQL servers by telling them about problems in their database applications before they occur. It is downloadable from the Oracle Software Delivery Cloud web site and is deployed within the safety of the customer data center.

A.2: 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

A.3: 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

A.4: 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.

A.5: 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.

A.6: How is the Enterprise Monitor web application architected?

The Enterprise Monitor web application comprises three components:

A.7: 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.

A.8: What versions of MySQL are supported by the MySQL Enterprise Monitor?

The MySQL Enterprise Monitor supports MySQL versions 5.1 and above.

A.9: 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.

A.10: What are the MySQL Enterprise Monitor Advisors?

Advisors filter and evaluate the information broadcast by the Monitoring Agents and present it to the Events page when defined thresholds are breached. They also present advice on how to correct the issue. There are more than 200 Advisors, all of which are enabled by default. Thresholds are the predefined limits for Advisors. If the monitored data breaches the defined threshold, an event is generated and displayed on the Events page. Advisor thresholds use a variety of different value types, depending on the monitored value. Some use percentages, such as percentage of maximum number of connections. Others use timed durations, such as the average statement execution time. It is also possible to check if specific configuration elements are present or correct.

A.11: 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

A.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.

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

See Section 23.1, “Providing Query Analyzer Data”.

A.3: What overhead can I expect when the MySQL Query Analyzer is installed and enabled?

The average overhead when in active collection mode is in the 15-20% range. In pass-thru mode the overhead is minimal, weighing in at 1-5% on most MySQL systems of average load.

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

For the complete features and benefits, visit the

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

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

A.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.

A.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

A.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.

A.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.

A.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.

A.11: How much degradation in performance does mysql-proxy introduce?

At the very least it's equivalent to a network hop in latency. The degradation is directly related to your average query execution time. If your queries execute in microseconds (which can happen if served from query cache) then the degradation will be higher, and noticeable. We've seen some applications that actually do work when they execute queries, the degradation is much less, and in some limited cases because of scheduling, the application actually has better throughput.

A.12: 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 23.1, “Providing Query Analyzer Data”.