An orders system sends payment instructions to an Amazon SQS queue. The consumer sometimes times out after it has already created the payment record but before it deletes the SQS message. As a result, the same instruction can be processed more than once. Which design best ensures the consumer remains resilient and does not create duplicate payments when the same instruction is delivered multiple times?

Assume the consumer will always delete the SQS message in the same execution path, and ignore the timeout case.

Timeouts and crashes do occur; assuming deletion always succeeds leads directly to duplicate processing.

Switch to SQS Standard because it provides exactly-once delivery, so duplicates cannot happen.

SQS Standard is at-least-once delivery; duplicates can still occur, and exactly-once is not guaranteed.

Increase the consumer timeout and reduce the number of retries so that duplicates rarely occur.

Reducing retries lowers frequency but does not guarantee correctness; resilience requires correctness under duplicates.

What does this SAA-C03 question test?

Static NAT maps one inside address to one outside address.

What is the correct answer to this question?

The correct answer is: Use idempotency: store a deterministic payment request identifier in a DynamoDB table and only create a payment when a conditional write indicates it was not processed before. — The key requirement is correctness under duplicate deliveries and partial failures. With SQS at-least-once delivery, the same message can be processed multiple times, especially when timeouts prevent message deletion. Implementing idempotency by persisting a deterministic identifier (for example, paymentInstructionId) and using a conditional write in DynamoDB ensures the payment record is created only once; subsequent attempts detect the existing processed state and skip or reconcile safely. Increasing timeouts or relying on deletion success doesn’t address the underlying delivery semantics. SQS Standard does not guarantee exactly-once behavior, so it cannot eliminate duplicates by itself. Option A ignores real failure modes and guarantees duplicates under timeouts. Option C is incorrect because SQS Standard does not provide exactly-once delivery. Option D may reduce duplicate frequency, but resilience requires safe handling even when duplicates occur, not merely fewer duplicates.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.