Exactly Once Delivery
Exactly Once Delivery is a messaging guarantee in distributed systems where each message is processed exactly one time, ensuring no duplicates and no lost messages. It is a critical property for applications requiring strict data consistency, such as financial transactions or event sourcing. Achieving this involves complex coordination mechanisms like idempotent operations, deduplication, and transactional messaging.
Developers should learn and implement Exactly Once Delivery when building systems that cannot tolerate duplicate or missing data, such as payment processing, order fulfillment, or real-time analytics pipelines. It is essential in scenarios where data integrity is paramount, preventing issues like double-charging or incorrect state updates. This concept is particularly relevant in stream processing frameworks and message brokers handling high-stakes data.