What is a dead letter queue in AWS

Question

What is the significance of a dead letter queue in AWS? Can someone help me with this? I am new to this term. Thank you in advance.

Answer 1

You can configure a SQS queue or a SNS topic as your dead letter queue. Any AWS Lambda function that is invoked asynchronously is retried twice before discarding the event. If the retries fail and the reason is unsure, then use Dead Letter Queues (DLQ) to direct the unprocessed events to an Amazon SQS queue or an Amazon SNS topic to analyze the reason of failure.

Answer 2

SQS dead letter queue is provided by AWS to handle failed messages so that we can letter debug a faulty message.

We can set redrive policy on a queue saying that if a message is not successfully processed by a consumer in say 5 times,sqs will send that message to a dead letter queue.