Message Queues and Asynchronous Processing Questions

Fundamental concepts of asynchronous systems that use message brokers and background job processing. Candidates should explain how messages are enqueued and consumed, acknowledgement semantics and visibility timeouts, retry strategies and dead letter queues, ordering and partitioning trade offs, idempotency and deduplication strategies, and common failure modes such as consumer crashes or poisoned messages. The topic also covers monitoring queue depth and latency and debugging delayed or failed jobs.