CSI Message Queuing & Event-Driven Architecture

Question 1

Which messaging pattern allows producers to publish messages to a topic that multiple consumers can independently subscribe to and receive?

Accepted Answer

Publish/Subscribe

Answer

Publish/Subscribe (pub/sub) decouples producers from consumers by routing messages through a topic, allowing multiple independent subscribers to receive each message.

Question 2

In Apache Kafka, what is the primary role of a partition within a topic?

Accepted Answer

To enable parallel processing and horizontal scalability

Answer

Partitions divide a topic across multiple brokers, allowing consumers in a consumer group to process different partitions simultaneously, enabling horizontal scalability.

Question 3

What is the purpose of a Dead Letter Queue (DLQ) in a message queuing system?

Accepted Answer

To hold messages that failed processing after maximum retry attempts

Answer

A DLQ captures messages that could not be successfully processed after exhausting retries, isolating them for inspection and preventing queue blockage.

Question 4

Which message delivery guarantee ensures that every message is delivered at least once but may result in duplicates?

Accepted Answer

At-least-once delivery

Answer

At-least-once delivery guarantees no message is lost by retrying on failure, but the trade-off is that consumers must handle potential duplicate messages idempotently.

Question 5

In event-driven architecture, what does the term 'event sourcing' refer to?

Accepted Answer

Storing state changes as an immutable sequence of events rather than the current state only

Answer

Event sourcing persists each state change as an ordered, immutable event log, allowing system state to be reconstructed by replaying events from any point in time.

(CSI) Certified System Integrator Practice Test

(CSI) Certified System Integrator Practice Test

CSI Message Queuing & Event-Driven Architecture