Amazon SQS supports dead-letter queues (DLQ)
▪ Messages can't be processed because of a variety of possible issues.
▪ Example; User places a web order with a particular product ID, but the product ID is deleted.
Code fails and displays an error, and the message with the order request is sent to a dead-letter
queue.
▪ The main task of a dead-letter queue is to handle the lifecycle of unconsumed messages.
▪ A dead-letter queue lets you set aside and isolate messages that can't be processed correctly
to determine why their processing didn't succeed.
▪ Setting up a dead-letter queue
▪ Configure an alarm for any messages moved to a dead-letter queue.
▪ Examine logs for exceptions that might have caused messages to be moved to a dead-letter queue.
▪ Analyze the contents of messages moved to a dead-letter queue.
▪ Determine whether you have given your consumer sufficient time to process messages.