Event rules and threshold rules differ from KPI rules in that Optimize evaluates data points against the rule as they are collected (that is, in real time) rather than waiting for a KPI collection interval (that is, an aggregation of data points collected over an interval). Event and threshold rules generally apply to types of data that require immediate response, such as an application unexpectedly shutting down or CPU usage exceeding unacceptable limits. Optimize maintains state for event rules so that you can track data over multiple intervals, but it does not maintain state for threshold rules. On the other hand, for capturing any individual order with a size greater than a million dollars, a threshold rule would be preferable to an event rule.

For more information on KPI, event, and threshold rules, see Chapter 5 “Defining Rules” in webMethods Optimize User’s Guide.