There are many cases in an Event's life when a system (either the system creating the event or a system transporting the event) might wish to only emit a portion of the events that actually happened. In a high throughput system where creating the event is costly, a system might wish to only create an event for 1/100 of the times that something happened. Additionally, during the transmission of an event from the source to the eventual recipient, any step along the way might choose to only pass along a fraction of the events it receives.
In order for the system receiving the event to understand what is actually happening in the system that generated the event, information about how many similar events happened would need to be included in the event itself. This field provides a place for a system generating an event to indicate that the emitted event represents a given number of other similar events. It also provides a place for intermediary transport systems to modify the event when they impose additional sampling.
- Type:
Integer - Description: The rate at which this event has already been sampled. Represents
the number of similar events that happened but were not sent plus this event.
For example, if a system sees 30 occurrences and emits a single event,
ratewould be 30 (29 not sent and 1 sent). A value of1is the equivalent of this extension not being used at all. - Constraints
- The rate MUST be greater than zero.