A key component of the solution is an event store. The event store system is immutable, sequential, and serves as the destination for the event streams from each service. Consumers of these events can then subscribe to and read the events of interest. The event store essentially serves as an event source for each consumer. Consumers maintain their own logic related to the filters that will be applied to determine whether an event is of interest. Each consumer also maintains their own pointer/offset into the event store to serially process the events.

Events can be generated either from the application layer or directly from the data layer. Generating events from the application layer provides visibility into and control over the flow of events, but this comes at the cost of having to manage and maintain the flow of events across all the producers and consumers. Having the events emanating from the data layer frees the application layer, and developers, from having to essentially build major pieces of an event-driven system within the application.