Queue & Async

Question 1

What is a message queue?

Answer 1

A message queue is middleware that enables asynchronous communication between services. Producers send messages to a queue; consumers process them independently, decoupling services.

Question 2

What are the benefits of message queues?

Answer 2

Benefits include: asynchronous processing, load leveling, fault tolerance, scalability, service decoupling, and ability to handle traffic spikes without overloading services.

Question 3

What is the difference between a queue and a topic?

Answer 3

Queue: point-to-point communication, one consumer processes each message. Topic (pub/sub): broadcast communication, multiple subscribers receive each message.

Question 4

What is Apache Kafka?

Answer 4

Kafka is a distributed streaming platform for building real-time data pipelines. It uses a publish-subscribe model with high throughput, durability, and message replay capability.

Question 5

What is RabbitMQ?

Answer 5

RabbitMQ is a message broker implementing AMQP protocol. It supports multiple messaging patterns (queue, pub/sub, routing), offers reliability features, and has flexible routing.

Question 6

What is message acknowledgment?

Answer 6

Acknowledgment confirms a message has been successfully processed. It ensures reliability: if consumer fails before acking, the message is redelivered to another consumer.

Question 7

What is idempotency in message processing?

Answer 7

Idempotency means processing the same message multiple times produces the same result. It’s crucial for handling duplicate messages and ensuring system reliability.

Question 8

What is a dead letter queue?

Answer 8

A dead letter queue stores messages that couldn’t be processed after multiple attempts. It prevents message loss and allows investigation of problematic messages.

Question 9

What is event-driven architecture?

Answer 9

Event-driven architecture uses events (state changes) to trigger and communicate between services. Services emit events when something happens; other services react by consuming events.

Question 10

What is backpressure?

Answer 10

Backpressure is a mechanism to handle situations where consumers can’t keep up with producers. It slows down producers or buffers messages to prevent system overload.