.NET Architecture & System Design Interview Question #44
What does exactly-once processing mean?
Caching, CDN, Queues & Asynchronous Processing Junior Beginner
Quick Interview Answer
Exactly-once processing means the intended business effect occurs once despite failures, retries, or duplicate delivery. Achieving this across distributed components is difficult and often depends on transaction boundaries, idempotency, deduplication, or technology-specific guarantees.
Detailed Explanation
Exactly-once processing means the intended business effect occurs once despite failures, retries, or duplicate delivery. Achieving this across distributed components is difficult and often depends on transaction boundaries, idempotency, deduplication, or technology-specific guarantees.
A broker advertising exactly-once delivery does not automatically make every external side effect exactly once. Architects should define precisely which operation and boundary the guarantee covers.
Code Example
Duplicate message
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Idempotency key / transaction
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Business effect applied once