SAP-C02 Visibility Timeout Practice Question

Correct answer & explanation

To prevent duplicate processing, the team should increase the SQS queue's visibility timeout to 6 minutes (option A). Since each message takes about 30 seconds to process, the default 60-second visibility timeout is too short; if processing exceeds 60 seconds, the message becomes visible again and is reprocessed. Increasing the timeout to 6 minutes (well above the 30-second processing time) ensures the message remains invisible until processing is complete. Additionally, switching to a FIFO SQS queue with content-based deduplication (option C) provides exactly-once processing semantics, eliminating duplicates regardless of visibility timeout. Option B is incorrect because reserved concurrency limits the number of concurrent Lambda executions but does not prevent duplicates from visibility timeout issues. Option D is incorrect because reducing batch size limits how many messages are polled at once but does not address the root cause of duplicate processing. Option E is incorrect because a dead-letter queue handles messages that fail repeatedly, not duplicates.