The Overview Dashboard shows a high level summary of the MySQL instances and hosts that are monitored by MySQL Enterprise Monitor.
The Overview summarizes various key statistics related to the group that is selected, such Database Availability, Connections, Database Activity, Query Response Times, and any current MySQL Instances or Hosts that have active Critical or Emergency level events against them. It is designed in this way to give you a quick high level picture of assets that require immediate attention, as well as give you an up to date profile of how MySQL Instances within environment are behaving.
By default the "All" group is selected, so the Overview summarizes these statistics for all MySQL Instances and Hosts that are monitored. If you have a specific group that you would like to focus on, then change the Group Overview selection:
The Database Availability statistics show an aggregate of availability statistics, generated by the MySQL Availability Advisor, for all MySQL Instances within the selected Group, and allows you to monitor your Service Level Agreements for availability.
The MySQL Availability Advisor must be enabled for this functionality to work. It is enabled by default.
Database Availability is computed by each individual MySQL Enterprise Agent attempting to make a connection to each monitored MySQL Instance on a frequent basis (by default every 1 second, but this is configurable within the Advisor), to check whether the MySQL Instance is actively accepting new connections.
Depending on the response from the MySQL Instance, the availability is broken down in to four categories:
Available: The instance was actively monitored, and we could make a new connection.
Up: The instance
status variable reported it was up when we last logged in, but
we were not actively monitoring at this time. This can happen
when you start monitoring for the first time from an Agent, or
if the Agent was down for some period of time.
Unreachable: The Agent could not get a
response from the MySQL Instance, however when we logged back in
we detected that the instance was up for that period of time
Uptime status variable. This can
happen for various reasons, such as a
max_connections limit being reached, or some
networking problem between the MySQL Enterprise Agent and the MySQL
Instance that is being monitored.
Down: The Agent could not get a response from the MySQL Instance at all.
For each time range, the bar chart is split up in to slices of time (1 or 2 pixels each, depending on the width of the display), which represent a period of time; Day = 4 minutes, Week = 20 minutes and Month = 2 hours. Within those slices, the time within each availability state is aggregated across all MySQL Instances within the selected Group, and shown as the percentage of the total time in the slice.
For example, if you have four MySQL Instances within the selected group, with three of them being up and one of them being down for a 4 minute period within the day, the slice representing those 4 minutes would be 75% dark green, and 25% red.
MySQL Availability reporting is only available when using a MySQL Enterprise Agent of version 3.0.0 and above.
The remaining Databases Statistics graphs are designed to show a high level picture of the concurrency (Connections - All MySQL Instances), throughput (Database Activity - All MySQL Instances) and response times (Query Response Time Index) of the MySQL Instances within the selected group. These allow you to quickly spot if the profile of activity within the environment has changed.
For more information on the Query Response Time index (QRTI), see Section 5.1, “Query Response Time index (QRTi)”.
The Current Problem MySQL Instances and Current Problem MySQL Hosts list the top 5 MySQL Instances and Hosts respectively, based on whether they have open events with a current status of either Emergency or Critical.
The results are sorted by the total time that each event has been within these statuses, by Emergency descending, and then Critical descending. This means that the MySQL Instances, or Hosts, that have had Emergency, then Critical events open for the longest will float to the top of the list.
This is extremely useful in environments that are monitoring many MySQL Instances, as it allows you to focus in to which MySQL Instances or Hosts to tackle next, by telling you those that have the most problems against them.
When a MySQL Instance or Host has any open Emergency events against them, the row for that asset will be shown in red:
The Emergency & Critical Events panel lists a stream of the currently open events with an Emergency or Critical status. These are listed separately to the Current Problem MySQL Instances or Current Problem Hosts panels, as these might not show all assets within an environment that is monitoring five or more of either asset type.
This allows you to see all current high priority events within a single panel for all monitored assets.