java-messaging-rabbitmq

Delayed retry in RabbitMQ is achieved using TTL combined with dead-letter exchanges. Messages are sent to a waiting queue with a per-message TTL, then dead-lettered back to the original queue for a second delivery attempt after the delay.

Message ordering in RabbitMQ is maintained by configuring consumer concurrency and prefetch control. Single-active consumers with a prefetch count of one ensure sequential processing, though this limits throughput compared to parallel worker queues.

Publisher confirms in RabbitMQ provide asynchronous acknowledgment from the broker to the producer. They ensure messages successfully reached the broker, enabling reliable messaging orchestration and preventing silent message loss during publish.

RabbitMQ consumers requeue failed messages when ack, nack, or reject handling is misconfigured without a dead-letter exchange. Implementing a retry strategy with DLX wiring and poison message handling stops infinite requeue loops.

Prefetch control in RabbitMQ limits unacknowledged deliveries per consumer, balancing load across async workers. Setting an appropriate prefetch count prevents consumers from being overwhelmed and optimizes worker reliability.