Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 255 discussion

D. Store the order in the database. Send a message that includes the order number to an Amazon Simple Queue Service (Amazon SQS) FIFO queue. Set the payment service to retrieve the message and process the order. Delete the message from the queue. This approach ensures that the order creation and payment processing steps are separate and atomic. By sending the order information to an SQS FIFO queue, the payment service can process the order one at a time and in the order they were received. If the payment service is unable to process an order, it can be retried later, preventing the creation of multiple orders. The deletion of the message from the queue after it is processed will prevent the same message from being processed multiple times. It's worth noting that FIFO queues guarantee that messages are processed in the order they are received, and prevent duplicates.

A. is not a suitable solution for preventing the creation of multiple orders. This approach does not guarantee the sequential and reliable processing of orders. B. is not an appropriate solution for preventing the creation of multiple orders. CloudTrail is primarily used for logging and auditing API activity, and invoking a Lambda based on the logged request does not ensure the correct order processing. C. is not a suitable solution. SNS is a publish-subscribe messaging service, and polling it may result in delayed processing and potential order duplication. D. is the correct solution. Using an SQS FIFO ensures that the orders are processed in a sequential and reliable manner, preventing the creation of multiple orders for the same transaction.

if the backend can not keep up, queue the tasks.

D. Store the order in the database. Send a message that includes the order number to an Amazon Simple Queue Service (Amazon SQS) FIFO queue. Set the payment service to retrieve the message and process the order. Delete the message from the queue.

The question is related in breaking down the flow. SQS is go-to choice to decouple & DB will be used to store

Why not A?

The use of a FIFO queue in Amazon SQS ensures that messages are processed in the order they are received.

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asnwer is d