CSI Message Queuing & Event-Driven Architecture 2

Question 1

In RabbitMQ, which exchange type routes messages to queues based on an exact match of the message's routing key?

Accepted Answer

Direct exchange

Answer

A direct exchange routes messages to queues whose binding key exactly matches the message's routing key, making it suitable for task distribution to specific workers.

Question 2

What is the CQRS pattern and how does it relate to event-driven architectures?

Accepted Answer

Command Query Responsibility Segregation — separates read and write models, often using events to sync the write side to read projections

Answer

CQRS separates command (write) and query (read) operations, and pairs naturally with event sourcing: commands emit events that update denormalized read models asynchronously.

Question 3

A system integrator needs to guarantee message ordering within a specific subset of events. Which Kafka feature supports this requirement?

Accepted Answer

Partition keying by a consistent message attribute

Answer

By assigning a consistent partition key (e.g., customer ID), all messages with the same key are routed to the same partition, preserving order for that key within Kafka's ordered partition log.

Question 4

Which integration pattern uses a persistent store to record outgoing messages before they are sent, ensuring they are eventually delivered even if the broker is temporarily unavailable?

Accepted Answer

Transactional outbox pattern

Answer

The transactional outbox pattern writes the message to a local database table within the same transaction as the business operation, then a relay process publishes it to the broker, preventing message loss.

Question 5

In event-driven microservices, what is a 'saga' pattern used for?

Accepted Answer

Managing distributed transactions across multiple services using a sequence of local transactions and compensating events

Answer

The saga pattern coordinates multi-step distributed transactions by chaining local transactions and using compensating transactions to roll back completed steps if a later step fails.

(CSI) Certified System Integrator Practice Test

(CSI) Certified System Integrator Practice Test

CSI Message Queuing & Event-Driven Architecture 2