Professional Data Engineer · Free Practice Question Medium
Question 9
A consultant has recommended that you replace an existing messaging system with Cloud Pub/Sub. You are concerned that your existing system has a different delivery guarantee than Cloud Pub/Sub. What kind of message deliver semantics does Cloud Pub/Sub guarantee?
- A Deliver at most once
- B Deliver at least once
- C Best effort but no guarantee
- D Deliver at most or deliver at least depending on configuration of the subscription
Reveal correct answer
Correct answer: B
Explanation
Cloud Pub/Sub has a deliver at least once guarantee. It does not have deliver at most once guarantee. It is possible the Cloud Pub/Sub could deliver a message more than once. See https://cloud.google.com/pubsub/docs/subscriber
Discussion
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