Event-driven design in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary benefit of using event-driven design in a distributed system?

Consider a distributed system where components communicate asynchronously. What is the main advantage of using event-driven design in such a system?

A It eliminates the need for any message queues or brokers.

B It forces all components to wait for each other, ensuring strict synchronization.

C It allows components to operate independently and react to events without tight coupling.

D It requires components to share a common database for communication.

💡 Hint

Think about how components communicate and depend on each other in event-driven systems.

Event-driven design enables components to work independently by reacting to events asynchronously, reducing tight coupling and improving scalability.

❓ Architecture

intermediate

Which component is essential in an event-driven architecture to decouple event producers and consumers?

In an event-driven architecture, what component helps to decouple the event producers from the event consumers?

A Event Broker or Message Queue

B Direct API calls between producer and consumer

C Shared Database Table

D Synchronous HTTP Requests

💡 Hint

Think about how events are passed without direct connection between components.

An event broker or message queue acts as an intermediary that stores and forwards events, allowing producers and consumers to operate independently.

❓ scaling

advanced

How does event-driven design improve system scalability compared to synchronous request-response design?

Compare event-driven design with synchronous request-response design. How does event-driven design help improve scalability?

A By forcing all components to wait for responses before continuing, ensuring consistency.

B By allowing components to process events asynchronously, reducing blocking and enabling parallelism.

C By requiring all events to be processed in a single thread to avoid race conditions.

D By eliminating the need for load balancers in the system.

💡 Hint

Think about how asynchronous processing affects resource usage and throughput.

Event-driven design allows components to handle events independently and in parallel, reducing wait times and improving throughput, which enhances scalability.

❓ tradeoff

advanced

What is a common tradeoff when using event-driven design regarding data consistency?

Event-driven systems often sacrifice something to gain scalability and decoupling. What is a common tradeoff related to data consistency?

A Eventual consistency instead of immediate consistency across components.

B Strong consistency with immediate updates everywhere.

C No need for data replication or synchronization.

D Guaranteed order of all events without delay.

💡 Hint

Consider how asynchronous event processing affects the timing of data updates.

Event-driven systems often use eventual consistency, meaning data updates propagate over time rather than instantly, trading immediate consistency for scalability.

❓ estimation

expert

Estimate the maximum event throughput for a system using a single event broker with 10 partitions, each handling 1000 events per second.

A system uses one event broker with 10 partitions. Each partition can handle 1000 events per second. What is the maximum total event throughput the system can handle?

A 100 events per second

B 100,000 events per second

C 1,000 events per second

D 10,000 events per second

💡 Hint

Multiply the number of partitions by the throughput per partition.

The total throughput is the sum of throughput of all partitions: 10 partitions * 1000 events/sec = 10,000 events/sec.