What is eventual consistency?

Definition:

Eventual consistency allows copies or derived views to differ temporarily while updates propagate. If no new changes occur and processing succeeds, those views converge. This is useful when a delay is acceptable, but the product must define what users see during that delay and how failed propagation is repaired.

Key points:

• Different copies may temporarily show different data.

• Without new writes, they converge after pending updates are applied.

• Suitable for some feeds or analytics; current stock or order allocation may need stronger guarantees.

• Examples include a report updating after an order is accepted, or a search index catching up with a profile change.

Interview point:

• Name the permitted delay and reconciliation mechanism; “eventually” without an operational bound is not a complete plan.