Dead letter queue.
also: DLQ · DLQs · dead-letter queue · dead letter queues · dead-letter queuesA queue where messages go after exceeding their retry limit, to be inspected, fixed and replayed instead of blocking the main queue.
the two-minute refresher
- The post office's dead letter office: undeliverable mail is kept, examined and sometimes re-sent.
- Keep the failure reason, attempt count and original payload with each message.
- Alert on DLQ growth: a DLQ nobody watches is data loss with extra steps.
- Replay after the fix, and make sure replay is idempotent.