An orders service publishes payment instructions to an Amazon SQS Standard queue. A downstream consumer sometimes times out or crashes after it has partially completed processing, causing the same instruction to be processed more than once. You must keep the design resilient without attempting to guarantee exactly-once processing. Which approach best handles duplicates safely?

Set the SQS visibility timeout extremely long so the message cannot be retried even after processing failures.

A long visibility timeout only delays retries. If a consumer fails after partial work, duplicates still occur later, and recovery becomes slower and riskier for real failures.

Switch to an SQS FIFO queue but remove error handling in the consumer so duplicates never occur.

FIFO can change ordering and reduce some duplicate scenarios, but it does not eliminate duplicates in all failure modes. Removing error handling reduces resiliency and can lead to lost or inconsistent processing.

Send all failed messages to a DLQ and rely on it to deduplicate messages that were already successfully processed.

A DLQ captures messages that fail repeatedly (after retry attempts / redrive conditions). It is for poison-message handling, not for deduplicating messages that were already successfully processed but later retried.

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: Make the consumer idempotent by deriving a deterministic idempotency key from the payment instruction (for example, the instruction ID), persisting the result of successful processing, and skipping re-processing when that key is already marked successful. — SQS Standard uses at-least-once delivery, so duplicates can occur when a consumer times out, crashes, or acknowledges only after incomplete processing. The resilient pattern is to make the consumer idempotent: use a deterministic idempotency key from the instruction, record successful completion in a durable store, and ensure that when the same message is delivered again the consumer detects the prior success and safely avoids repeating side effects. This achieves correctness without attempting exactly-once delivery. A postpones retries but does not remove the duplicate-processing risk. C is incorrect because FIFO plus removing error handling is not a duplicate-suppression guarantee and harms resiliency. D is incorrect because DLQs handle messages that repeatedly fail; they do not deduplicate successfully processed work.

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.