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MySQL Enterprise Monitor 2.3 Manual
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2.7 The Replication Tab


MySQL Enterprise subscription, MySQL Enterprise Monitor, MySQL Replication Monitor, and MySQL Query Analyzer are only available to commercial customers. To learn more, see:

Navigate to the Replication page by choosing the Replication tab. This page summarizes the state of your replication servers; you can drill down to see details about any master or slave. Using this page helps you avoid running the SHOW SLAVE STATUS command over and over on multiple servers; for consistency, the Replication page uses some of the same keywords as the output from that command.


Set up agents to monitor each master and slave server. Only servers that are monitored appear on this page.

The Replication page groups all master servers with their slaves. Masters and their slaves are autodiscovered and a grouping is created, based on the way that the servers are interconnected (known as the replication topology). This grouping shows up on the replication page and also in the Heat Chart on the Monitor tab. Scans run on a five minute interval, so depending upon the order of discovery, it can take as long as 2 polling intervals to create a complete group.

Figure 2.8 MySQL Enterprise Monitor User Interface: Replication Groups

MySQL Enterprise Monitor User Interface: Replication groups

Discovery events are logged to the Replication log. To view this log, navigate to the Settings page and choose the Logs link. View all replication-related events by clicking the Replication link. This log can be a useful tool for debugging the replication topology discovery process.


For discovery to work properly, the agent must be installed on the same machine as the server you are monitoring. Do not use remote monitoring.

You can manage replication groups from the Manage Servers page in the same way as other groups. However, any slaves removed from a server group are automatically restored to that group. You can also add non-slaves to a replication grouping. For more information about server groupings see Section, “Grouping Servers”.

Replication Page Details

Choose a value from the Refresh drop-down list box to set the rate at which information is updated. This refresh rate applies only to the information presented on this page: It is independent of the rate set for the Monitor tab.

The following columns describe replication master and slave servers:

  • Servers: Displays the group name and any servers that are part of the group. Levels of indentation in this column show the relationship between master servers and their slaves. The icon next to each server indicates if the server is enabled for semi-synchronous replication or not. A gray disabled-style icon indicates that semi-synchronous replication is not available.

  • Type: Indicates the topology of a server group or in the case of individual servers, whether a server is a master, a combined master/slave, or a slave.

  • Threads: Displays information about the two dedicated replication threads that run on the slave server. Both threads must be running for the slave to work properly. IO reports the status of the slave I/O thread. SQL reports the status of the slave SQL thread.

  • Time Behind: The interval that the slave is behind the master, in hh:mm:ss format. This column is blank if a server is a master. Typically, you try to keep this value low.

  • Binary Logs: Displays information about the binary log file. Current File shows the binary log file name. Position shows the current position in the binary log file.

  • Master Position: Displays information about the binary log position from the master server. Binary Log shows the master binary log file name. Position shows the current position in the master binary log file.

  • Log Space: Displays the sizes of log files related to replication. Binary Logs shows size information for the binary log files. Relay Logs shows size information for the relay log files.

  • Last SQL Error: The most recent error encountered by the slave SQL thread.

  • Last IO Error: The most recent error encountered by the slave I/O thread.

  • Unlabeled Column: To edit a server group name, click on the applicable rename group link under this column.

Most column headings are active links; click the header to change the display order. Sorting works differently for different column groupings. Click the Seconds Behind header to order servers by the number of seconds they are behind their master. The server topology is respected regardless of sort order. For example, in a TREE topology, ordering occurs within branches only.

If the agent is down, servers show in bold red in the Servers column. The Slave IO and the Slave SQL columns display stopped in red text if these threads are not running. If an agent is down, the last know status of the IO or SQL threads is shown in italics.

Clicking a master server opens a dialog box that displays information about the server. The information shown includes:

  • The number of slave servers.

  • The binary log file name.

  • The binary log position.

  • Which databases are replicated and which not.

The dialog box also includes a link to hide or show the slave servers.

Clicking a slave server opens a dialog window showing extensive information about the slave.

Usage Notes

For information on the kinds of problems you might find while monitoring replication, and how to solve them, see Troubleshooting Replication and Improving Replication Performance.

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