Question 110
A fleet sends telemetry continuously; backend consumers require independent processing rates and resilient buffering during outages. Which limitation must be considered before claiming the issue is fully resolved?
Explanation
Correct Answer
At-least-once delivery requires deduplicating side effects at consumers. This caution prevents extrapolating beyond the specific evidence or product boundary. Event systems decouple delivery from processing and retry behavior. The unresolved point should be tested using producer throughput, subscription backlog and consumer acknowledgment patterns rather than assuming a working interface proves full compliance or resilience.
Incorrect Answers
Event acknowledgments alone prove downstream business side effects are exactly once. This limitation is framed as a blanket exception, but the case requires a different, narrower caution. The relevant boundary is that at-least-once delivery requires deduplicating side effects at consumers. Event systems decouple delivery from processing and retry behavior. Inspect producer throughput, subscription backlog and consumer acknowledgment patterns.
Using Pub/Sub guarantees consumers can never process one event twice. The proposed claim mistakes an incomplete signal or product feature for a universal guarantee. The relevant boundary is that at-least-once delivery requires deduplicating side effects at consumers. Event systems decouple delivery from processing and retry behavior. Inspect producer throughput, subscription backlog and consumer acknowledgment patterns.
Durable delivery automatically supplies application-layer idempotence. This claim exceeds the evidence and ignores an important risk or operational dependency. The relevant boundary is that at-least-once delivery requires deduplicating side effects at consumers. Event systems decouple delivery from processing and retry behavior. Inspect producer throughput, subscription backlog and consumer acknowledgment patterns.