A payments platform must process each account's transactions strictly in arrival order, prevent a publisher's retries from creating duplicate charges, and sustain several million messages a day with predictable throughput. Which messaging service fits?
Show answer and explanation
Answer: A
Service Bus Premium provides dedicated messaging capacity, and sessions guarantee first-in, first-out delivery per session key, such as an account ID. Duplicate detection, configured with a history window, discards messages that repeat a message ID, which stops a retrying publisher from causing a second charge. Premium also handles high daily volume predictably. Event Hubs preserves order within a partition but has no built-in duplicate suppression. Event Grid is a push router with at-least-once delivery and no session ordering. Storage queues offer no FIFO guarantee and no duplicate detection.
Why the other options are wrong
- B. Event Hubs keeps ordering within a partition and suits streaming, but it has no built-in duplicate detection, so retries could still produce a second charge.
- C. Event Grid routes events to subscribers with at-least-once delivery and no per-account ordering, so duplicate and out-of-order deliveries are possible.
- D. Storage queues have no FIFO guarantee and no duplicate detection. Visibility timeouts can cause the same message to be processed twice.