Event Sourcing as Architecture Practice

Event sourcing is often described as an architecture practice. In the Cohesive System Model, the technical mechanics are captured by event sourcing as a realization substrate pattern.

Problem

Event sourcing addresses the problem of preserving the committed history that explains current state, rather than persisting only a latest state record.

Cohesive Formulation

The practice realizes persistence as a durable sequence of committed endogenous events. Reconstitution folds that committed event schedule into current state.

The important distinction is:

attempted input != committed endogenous event

Only committed events are state actions for the target entity. That is why event sourcing is also a consistency practice: the event history is the authoritative history of valid state transitions.

In the Model

Event sourcing supports audit, replay, projection rebuild, temporal queries, and state reconstitution. It also raises operational concerns around schema evolution, idempotency, ordering, snapshots, retention, and event publication.