MySQL Enterprise Monitor Glossary

These terms are commonly used in information about the MySQL Enterprise Monitor product.



A piece of logic that collects specific data from monitored Assets, optionally saves data to be returned for graphing and reporting purposes, and optionally generates Conditions, which are collected into Events. Advisors can be in one or more Categories.

The MySQL Enterprise Monitor product comes with a number of standard advisors. Based on your organization's particular needs, you may create or adapt custom advisors.

See Also alarm, collection, custom, notification, rule, schedule, standard.

advisor category

A set of Advisors that are designed to enforce MySQL best practices for that specific category. For example, there are predefined advisor categories such as Administration, Availability, Cluster, Replication and Security.

See Also advisor.


The MySQL Enterprise Monitor component that actively collects data from a host and its MySQL server instances. The data is transmitted to the Service Manager.

See Also instance, Service Manager.


A term from MySQL Enterprise Monitor 2.x that was replaced with events. Events are handled using event handling, which determines how they act when a potential problem is discovered. For example, an email might be sent.

See Also alert, Critical, event, notification, Warning.


A term from MySQL Enterprise Monitor 2.x that was replaced with events. Events are handled using event handling, which determines how they act when a potential problem is discovered. For example, an email might be sent.

See Also advisor, alarm, event, notification, SMTP, Warning.


The web server that runs the Tomcat servlet container that powers the UI. The MySQL Enterprise Monitor Service Manager installation includes the Apache web server.

See Also Dashboard, Service Manager, Tomcat.


A component that the MySQL Enterprise Monitor product monitors, such as a MySQL server instance, or a CPU or file system within a server machine. Contrast with metric, which is a property within the component that is measured.

See Also instance, metric.

Asset Selector

The Groups shown in the Asset Selector are the ones you create and manage (on the MySQL Instances Dashboard, or during Agent installation) and those that are discovered automatically from monitoring replication topologies. It is on the left side of many UI pages that controls content in the main-body of the page.

See Also asset, Dashboard, graph.


The mechanism that detects the set of master, slave, and master/slave servers in a replication configuration, and displays the topology in the Server tree.

See Also Asset Selector, master, replication, slave, topology.


best practice

Within the MySQL Enterprise Monitor product, a best practice is a specific rule backed up by a metric. When a threshold value is reached, the Service Manager raises an alarm.

See Also alarm, metric, rule, Service Manager, threshold.

blackout period

A function of Event Notification, it is a time period where events do not trigger notifications via the Event Handler, in that information is not reported from a MySQL Server. Typically, this is during a maintenance period when the database might go through an unusual workload that does not require raising any notifications.

See Also Agent, instance, notification.


An aspect or component of a system whose capacity imposes a limit on performance. In MySQL Enterprise Monitor, you identify bottlenecks in areas such as I/O or memory usage using graphs, and use advisors to automatically raise alerts when problems occur.

See Also advisor, alert, graph.


The bundled MySQL server refers to the MySQL server that can be installed along with the MySQL Enterprise Monitor product, to serve as the repository for the collected data.

See Also repository.



The C programming language.

canonical query

A synonym for normalized query.

See Also normalized query.

chain replication

In replication, a kind of topology where each server acts as a master/slave server, connected to at most two other servers.

See Also circular replication, master/slave, replication, topology.

circular replication

In a replication configuration, a topology where every server is both a master and a slave, connected to two other servers, forming a ring structure. Forms a ring structure.

See Also replication, ring replication, topology.


A set of related advisors.

See Also advisor.


A software component (analogous to a driver) that provide connectivity to the MySQL server for client programs. MySQL comes with connectors for several programming languages and frameworks. The MySQL Enterprise Monitor product includes plugins for certain collectors, to help monitor queries sent by application programs and use that data within the Query Analyzer.

See Also Connector/J, Connector/Net, Connector/PHP, query, Query Analyzer.


The Connector for applications written in the Java programming language. It communicates directly with the MySQL server without going through the libmysqlclient shared library.

See Also Connector, Java.


The Connector for applications written with the .NET programming framework. It communicates directly with the MySQL server without going through the libmysqlclient shared library.

See Also .NET, Connector.


The Connector for applications written in the PHP programming language. The mechanism for communicating with the MySQL server may differ depending on the version of PHP involved.

See Also Connector, PHP.


The MySQL Enterprise Monitor product interfaces with many different databases and other kinds of servers. Each of these components can have its own login and security credentials. MySQL Enterprise Monitor pulls performance data from the MySQL servers that you monitor, stores the resulting data in a repository that is also a MySQL server, and sends alerts by communicating through other kinds of servers such as SMTP for e-mail alerts and NMS for SNMP traps. It pulls support-related data from the My Oracle Support site. You view the results in the UI, which is protected by its own login and optionally by LDAP authentication.

See Also Dashboard, LDAP, NMS, repository, SMTP, SNMP.


A high severity level for alarms. Within a rule, you can designate the threshold values that specify whether an alarm triggers a Critical, Warning, or Informational alert.

See Also advisor, alarm, event, rule, threshold, Warning.


User-created rules and graphs. Contrast with standard.

See Also graph, rule, standard.



The Dashboard menu contains several pages (dashboards) for viewing and configuring MySQL Enterprise Monitor. This includes dashboards for the Overview, Replication, and MySQL Instances.

See Also Service Manager, Tomcat, What's New tab.

data collection item

Data values derived from server status variables, operating system status information, and MySQL table information. You can reference these items using mnemonic names in expressions when you create or edit rules.

See Also expression, rule.



The highest severity level for an advisor. Within an Advisor, you can designate the threshold values that specify whether an event triggers an Emergency, Critical, Warning, or Informational event.

See Also Critical, event, Warning.


A slightly more comprehensive synonym for alarm Evaluating a rule generates an event. The result of an event can be success if everything is OK. An alarm is raised only if something goes wrong. You monitor events using the Events tab, and by setting Event Handling.

See Also alarm, alert, Critical, notification, Warning.


A textual report showing the internal mechanisms used by a query, and estimates for the cost, such as amount of data to process, involved in each step. Performance monitoring involves checking whether queries that are slow or frequently run could be sped up or made less resource-intensive, by examining the EXPLAIN plan to check if the MySQL optimizer has chosen the most efficient ways to process indexes, order join clauses, and so on. The MySQL Enterprise Monitor product includes a number of features for visualizing EXPLAIN plans. These features are language-dependent, relying on support in the various Connectors for programming languages and frameworks.

See Also query.


The part of a rule that tests a metric against a threshold value.

See Also alarm, metric, rule, threshold.



Additional considerations apply when the server you are monitoring is separated from the Service Manager by a firewall.

See Also remote, Service Manager, SSL.

full table scan

An aspect of a SELECT query that often indicates a performance or scalability issue. The query scans every row in a table, rather than using an index to look up a subset of rows. It can be a non-issue for small tables that are cached in memory. It can be unavoidable when querying large tables to prepare reports. Performance issues are most likely when the table being scanned is involved in a join operation, when the query is run frequently, or when the result set only references a small fraction of the rows in the table.

To diagnose possible issues due to full table scans, choose a time period of heavy SQL activity from one of the graphs, use the Query Analyzer to locate queries that process large numbers of rows, and examine the explain plan for the queries. The notation in the explain plan that indicates a full table scan is Type=ALL.

See Also EXPLAIN plan, graph, query, Query Analyzer.



A visual representation of server activity, resources, or other metrics over time. You monitor graphs using the Graphs tab.

See Also Heat Chart, metric.



An implementation detail from MySQL Enterprise Monitor 2.x that is no longer present. A heartbeat signal that is sent from an Agent to the Service Manager was defined as the heartbeat, and was present in the connecting URL.

See Also Agent, Service Manager.

Heat Chart

A special chart from MySQL Enterprise Monitor 2.3 that showed the status of critical rules. This was replaced with the Overview dashboard.

See Also advisor, Dashboard.


A computer running one or more instances of MySQL server. Typically each host is monitored by a MySQL Enterprise Monitor Agent.

See Also instance, MySQL server.



A mysqld daemon running on a MySQL server. There might be multiple instances running on the same server machine. An instance is one of the kinds of asset that the MySQL Enterprise Monitor product can monitor.

The MySQL Instances dashboard manages the instances, and the MySQL Process Discovery advisor discovers local instances on the host that the Agent is installed on.

See Also asset.


A persisted instance of a run-time metric evaluation. These may store the raw metric data, or the result of an expression or function against a metric. Instruments are generally stored for things that will show in the GUI, such as graph data.

See Also graph, metric.


Core information about a host or MySQL server instance. This data is collected by the Agent. The inventory includes details such as the MySQL server version number, supported storage engines and replication configuration. The data in the inventory helps to determine what other kinds of data can be collected from the hosts and MySQL servers.

See Also Agent, instance, replication.



The MySQL Enterprise Plugin for Connector/J enables any application using the Connector/J JDBC driver to supply query analyzer information directly to MySQL Enterprise Service Manager. Information is sent to the MySQL Enterprise Service Manager for analysis without any need to modify your applications.

The MySQL Enterprise Monitor product is also partly built on Java technology, using the Tomcat servlet container for the web-based GUI. It uses a JVM on the machine that runs the Service Manager, its performance is affected by the Tomcat configuration parameters, the Agent is written in Java, and during troubleshooting you might use diagnostic information from the Java environment.

See Also Connector/J, Dashboard, JDBC, plugin, Query Analyzer, Tomcat.


The underlying database API used by many Java applications, including the Connector/J component.

See Also Connector/J, Java.



An authentication mechanism that can control access to the UI. On Linux, Unix, and OS X systems, you might have a separate LDAP server where each user has their own credentials. On Windows systems, the LDAP protocol is used to connect to an Active Directory server for the same authentication purposes. Typically, you map LDAP roles to corresponding MySQL Enterprise Monitor roles, to enable groups of users to have basic or administrative access to the Dashboard without configuring each user individually, or giving them a new user ID and password, or requiring extra work to revoke access when they leave the organization.

See Also credentials, Dashboard, role.

log file

The MySQL Enterprise Monitor product manages log files for the Tomcat, repository, and Service Manager components, as well as a configuration report pertaining to the initial installation. You can view each of these configuration files through the UI, or by examining the physical file.

See Also Dashboard, repository, Service Manager, Tomcat.


A programming language that is used for parts of the Aggregator and Service Manager. Although you do not need to know this language to operate the MySQL Enterprise Monitor product, sometimes you specify options containing file paths related to Lua scripts or libraries.

See Also Agent, Query Analyzer, Service Manager.



In a replication configuration, a database server that sends updates to a set of slave servers. It typically dedicates most of its resources to write operations, leaving user queries to the slaves. In complex topologies, a server can be both a master and a slave, known as a master/slave.

See Also master/slave, replication, slave, topology.


In replication, a server that acts as a slave to receive updates from another server, and also acts as a master to propagate changes to another set of slave servers. Keeps the top-level master from having to service too many slaves, and allows certain kinds of changes to be propagated to a subset of slaves. This topology is represented as a tree, with all the intermediate nodes being master/slave servers.

See Also master, replication, slave, topology, tree.


Any property that is measured using a numeric value. Within MySQL Enterprise Monitor, such measurements can be displayed over time as a graph, or an alert can be sent when a threshold value is reached. Each metric is collected from an asset. For example, how much time is taken by a database query, or how full is the file system on a server machine.

See Also alert, asset, graph, threshold.

mixed replication

In a replication configuration, a kind of topology consisting of different combinations of master, slave, and dual-purpose master/slave servers.

See Also chain replication, circular replication, master, master/slave, replication, slave, topology, tree.


To view information about the state, health, activity, and history of a resource such as a MySQL server instance. Monitoring can help to diagnose problems, spot worrisome trends before they turn into problems, reassure when systems are operating normally, and notify when an operator needs to take corrective action. With MySQL Enterprise Monitor, the component you interact with during monitoring is the UI.

See Also Dashboard, instance.

My Oracle Support

The web site for filing bugs and service requests with Oracle Support. (Commercial customers such as MySQL Enterprise Monitor users now use the official Oracle support channel rather than the MySQL bug database.) In MySQL Enterprise Monitor, you interact with the support site through the What's New tab.

See Also service request, What's New tab.

MySQL server

The MySQL database instance running on a host computer. More than one MySQL instance can run on the same computer, either as separate mysqld processes or through virtualization.

See Also instance.



A programming framework used by many Windows applications, including the Connector/Net component.

See Also Connector/Net.


Acronym for Network Management System, a type of monitoring system that is separate from the MySQL Enterprise Monitor product. If your network has this kind of monitoring capability, MySQL Enterprise Monitor can notify the NMS of network issues by translating events into SNMP traps.

See Also event, SNMP.

normalized query

A condensed form of the query text used to treat similar queries as if they were identical, for monitoring performance. When MySQL Enterprise Monitor normalizes queries, it disregards differences in keyword capitalization, whitespace, and most comments. It replaces literal values with placeholders and transforms multi-row insert statements and IN clauses, to group similar statements with different parameters when measuring how much time is consumed by a particular type of query.

See Also canonical query, query.


A low severity level for events. Within an advisor, you can designate the threshold values that specify the severity level that is triggered.

In 2.x, this was known as the "informational" severity level.

See Also advisor, Critical, event, rule, threshold, Warning.


The e-mail or other form of communication triggered by an alarm. Notifications are defined using Event Handlers.

See Also alarm.

notification group

A collection of users who should receive a notification when advisor alerts occur. These users might have login credentials for the UI, but this is not a requirement.

See Also alert, Dashboard, notification.



A scripting language typically embedded within web pages.

See Also Connector/PHP.


In the MySQL Enterprise Monitor product, a component that sits between the database and applications that use a particular language-based Connector. It collects query data from both standalone and web-based applications, for MySQL Enterprise Monitor to monitor. For example, there is the MySQL Enterprise Plugin for Connector/Net, and the MySQL Enterprise Plugin for Connector/J. The mechanism for transferring the data, such as whether the data flows through the Aggregator or the Proxy, depends on the particular connector.

See Also Connector, proxy.


It can accept queries from user applications, forward them to a MySQL server, and return the query results back to the application. You rearrange the TCP/IP ports so that the application communicates with the proxy instead of the database, either by changing the port where the application communicates with the database, or the port where the database listens.

See Also Agent.



QRTi stands for "Query Response Time index". It is a "quality of service" measurement for each query, and it uses the Apdex formula for that calculation. For more information about Apdex, see: Apdex on Wikipedia.

See Also Query Analyzer.


An abbreviation for Query Analyzer used in some keyword names.

See Also Query Analyzer.


In the MySQL Enterprise Monitor context, any SQL statement whose performance might be monitored. Includes not just SQL SELECT queries, but also DML statements such as INSERT, UPDATE, and DELETE, and DDL statements such as CREATE TABLE and TRUNCATE TABLE.

See Also normalized query, slow query log.

Query Analyzer

The MySQL Enterprise Monitor component that tracks data about MySQL queries and summarizes that data using graphs and tables. You interact with it (for example, filtering the displayed queries or selecting a specific time period) using the Query Analyzer tab in the UI.

See Also Dashboard, graph, query.



Additional considerations apply when the server you are monitoring is separated from the Service Manager, for example by a wide-area network or by a firewall.

See Also firewall, remote monitoring, SSL.

remote monitoring

An Agent on one host that monitors different hosts, and MySQL instances on different hosts.

Remote monitoring has limitations, versus local monitoring. Remote monitoring does not provide Operating System level data, such as CPU, file, and network utilization information.

See Also heartbeat, remote.


A set of database features that mirrors the same data across a set of servers. Used for reliability in case of server failure, and to speed up queries by dividing the work across servers. Because replication involves so many aspects of reliability and performance, it is an important aspect to monitor and has a dedicated Replication dashboard in the UI.

See Also Dashboard, Replication dashboard, topology.

Replication dashboard

A dashboard page within the UI that monitors aspects of replication. See Section 14.3, “Replication”.

See Also Dashboard, replication.


The database that stores the monitoring data collected by the MySQL Enterprise Monitor product. It can be a separate database instance that is part of the MySQL Enterprise Monitor installation (the bundled MySQL server), or you can use an existing database of your own. The bundled MySQL server is a level of MySQL database that is fully tested with the MySQL Enterprise Monitor product, and can be kept separate from your other databases to avoid any extra load on them. You might use an existing server that has spare capacity, fast storage devices, tuned configuration parameters, a backup system, or other conveniences that can benefit the MySQL Enterprise Monitor data storage as well.

See Also bundled, instance.

ring replication

See circular replication.


A level of access privilege for the UI. One of manager (highest privilege), dba, read-only, or agent (specialized privilege for sending data). Each user account registered with the Dashboard must have one of these roles. Components such as the Agent and the Aggregator use the agent role. To simplify the process of granting credentials for large numbers of users, you can map LDAP roles to these MySQL Enterprise Monitor roles.

See Also Agent, credentials, Dashboard, LDAP.


A test consisting of an expression and one or more threshold values that correspond to different alert levels. When the value of the expression reaches one of the threshold values, an event is generated. Depending on how you configure the rule, the event can result in an alarm, a notification, or both.

See Also advisor, alarm, event, expression, notification, threshold.



Determines how often each advisor is evaluated.

See Also advisor.


A dynamic filter against an asset class.

See Also asset.

Service Manager

The core MySQL Enterprise Monitor component that receives the monitoring data from the Agent, Aggregator, and Query Analyzer components. It displays this information through the GUI web-interface, and manages the Advisors, Events, and Event Handlers, as well as access to Reporting, Graphing, and Query Analysis.

See Also advisor, Agent, alert, Dashboard, Query Analyzer, rule.

service request

Generic term for a bug that you have filed or a support request that you have opened, on the My Oracle Support site. Formerly, we referred to these as support issues.

See Also My Oracle Support, support issue.


A measure of the seriousness of an Event. Event Handling policies can take into account the severity level in determining the appropriate course of Notification action.

See Also alarm, alert, rule.


In a replication configuration, a database server that receives updates from a master server. Typically used to service user queries, to minimize the query load on the master. In complex topologies, a server can be both a master and a slave, known as a master/slave.

See Also master, master/slave, replication, topology.

slow query log

A MySQL Server facility for tracking queries that consume considerable time and resources. MySQL Enterprise Monitor provides more information about query performance than the slow query log, and does not currently use the slow query log itself.

See Also query.


The e-mail protocol for sending alerts as e-mail messages. To send alerts this way, you configure e-mail settings similar to those in an e-mail client.

See Also alert.


A protocol for sending event notifications (SNMP traps) to an NMS. The MySQL Enterprise Monitor product can turn notifications for selected rules into SNMP traps. In contrast to typical alerts that are only raised when some issue occurs, SNMP traps are broadcast for all state changes, so that corrective action can be cancelled when an issue is cleared.

See Also alert, NMS, notification.


For MySQL Enterprise Monitor, the default port used for SSL connections is 18443. If you are connecting using SSL, the built-in MySQL Enterprise Monitor certificate is self-signed and may be highlighted as unsafe within the browser on initial connection. To prevent problems accessing the site, add an exception for the certificate to your browser for this server.


The predefined rules and graphs supplied as part of the MySQL Enterprise Monitor product. Contrast with custom.

See Also custom, graph, rule.

Status Summary

The Status Summary widget is displayed on top of every page, updates dynamically, and shows current status counters for Hosts monitored, MySQL Instances monitored, MySQL Instances with invalid connection configurations, Unmonitored MySQL Instances, and Emergency Events. The counters are live links for displaying details or resolving the issues they are reporting.

support issue

Former term for bugs and service requests. In the My Oracle Support system, now known as a service request, which is the preferred term.

See Also service request.


table scan

See full table scan.


The cutoff value in a rule. When the rule's expression passes this value, an alert is triggered. There can be different threshold values to trigger the different level alerts.

See Also alert, Critical, expression, rule, Warning.


A component of the Service Manager, the servlet engine that powers the UI.

See Also Apache, Dashboard, Java, Service Manager.


In a replication configuration, the way in which the different master, slave, and dual-purpose master/slave servers are connected. In MySQL Enterprise Monitor, the configurations are classified in the Replication Tab as one of TREE, RING, or MIXED.

See Also master, master/slave, replication, slave.


A data structure often used to represent relationships between MySQL servers. In the UI, servers are displayed in the Server Tree sidebar. In a replication configuration, setting up some machines as dual-purpose master/slave servers produces a nesting relationship that is represented in the Server Tree.

See Also Asset Selector, Dashboard, master/slave, replication.


Predicting when a problem may occur. For example, predicting that a disk will run out of disk space 30 days in the future.



The UI is a web-based interface to the MySQL Enterprise Service Manager. The back end is a Java application powered by the Tomcat server.

See Also Dashboard.


A unique identifier used to distinguish each MySQL instance, host machine, and agent. Because there is so much flexibility in spreading components across multiple systems or running multiple instances and agents on the same system, the combination of these different UUIDs identifies where information came from and the source of any issues. Always generate a new UUID for any one of these components, rather than copying or reusing an existing UUID value.

In MySQL Enterprise Monitor, the UUID for a MySQL server is stored in the table mysql.inventory. When a component such as the Agent or a Connector plugin connects to that MySQL server, the applicable MySQL user must have privileges to read this table.

See Also Agent, instance.



A medium severity level for alarms. Within a rule, you can designate the threshold values that specify for each severity level.

See Also advisor, alarm, alert, Critical, event, notification, rule, threshold.

What's New tab

A page within the UI that provides updates and news related to MySQL Enterprise Monitor and your My Oracle Support account.

See Also Dashboard, My Oracle Support.