{CodeRoyale}
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Multiple ChoiceBeginner 45s

At-least-once semantics

A queue guarantees at-least-once delivery. What must producers or consumers handle?
Options
  1. 1Nothing, at-least-once guarantees processing exactly once
  2. 2Message loss on broker restart, since unpersisted messages drop
  3. 3Only ordered delivery, since ordering implies no duplicates
  4. 4Duplicate deliveries, so consumers must be idempotent
system-designmessagingidempotency

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