In addition to the maintaining the current value for a metric (AKA fact), a number derived metrics are available. These derived properties can be useful to understand the behavior. They can also be used in sensors for automation. To view these in Enterprise Manager, (1) left click on any fact and then (2) move the mouse to the white space, right click and select Show Properties. This shows the most commonly use derived metrics (3). Some of the key ones are:
- Maximum, minimum, and average values.
- Updates and Changes indicate how volatile the data is.
- Updates is the number of times this fact has been published
- Changes is the number of times the value changed when published
- Update latency is the time between the last 2 updates and
- Change latency is the time between changes (a high value means it has not changed recently)
- Update and change age are the time elapsed since it last updated or changed (the actual time is also shown). These are useful in automation to identify stale data.
- Statistical metrics are available, see Administrator's Guide for more information on using these.
- Expiry is the amount of time after publishing that the fact will automatically be deleted (in milliseconds). Expiry-Timer is the amount of time it has left before expiring.
- Some facts are counters which report the last interval of data. These have a derived metric counter, that it is the total number for the counter.
It is not required to close the properties window to select a different fact, simply click on it.