Aggregate Event Stream Lifetimes

Types of aggregates

In an event-sourced system, there are two kinds of aggregates:

• Short-lived aggregates

• Long-lived aggregates

Short-lived aggregates

Short-lived aggregates will not see many events in their short lifetime. Examples of a short-lived aggregate would be Order from the Ordering module and Basket from the Shopping Baskets module. Both exist for a short amount of time, and we do not expect them to see many events.

The performance of short-lived aggregates and streams with few events in general will not be a problem. The small number of events can be read and processed quickly.

Long-lived aggregates

Long-lived aggregates will see many events over their very long lifetime. Examples ...