Entry and exit flow in LLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Entry and Exit Points in System Design

In a typical web application, what is the primary role of the entry point?

A It handles incoming requests and routes them to the appropriate components.

B It stores all user data permanently.

C It manages the database schema migrations.

D It performs background batch processing tasks.

💡 Hint

Think about where the user first interacts with the system.

The entry point is where the system receives requests and directs them to the right place for processing.

❓ Architecture

intermediate

Tracing Request Flow Through Entry and Exit Points

Which sequence best represents the flow of a user request through a layered system architecture?

A 1, 2, 4, 3

B 2, 1, 3, 4

C 1, 3, 2, 4

D 1, 2, 3, 4

💡 Hint

Follow the natural order from request to response.

The request starts from the user, passes through entry point for authentication, then business logic, and finally the exit point returns the response.

❓ scaling

advanced

Scaling Entry and Exit Points for High Traffic

When designing a system to handle millions of requests per day, which approach best improves the scalability of entry and exit points?

A Use load balancers to distribute incoming requests across multiple entry point servers.

B Increase the size of a single server to handle all requests without distribution.

C Remove the exit point to reduce processing time.

D Direct all requests to a single database to simplify data access.

💡 Hint

Think about spreading the load rather than concentrating it.

Load balancers help distribute traffic evenly, preventing any single server from becoming a bottleneck.

❓ tradeoff

advanced

Tradeoffs in Entry and Exit Flow Design

What is a key tradeoff when adding complex validation logic at the entry point of a system?

A Simpler code but higher risk of data loss.

B Reduced security but faster response times.

C Improved security but increased latency for each request.

D Lower server costs but less scalability.

💡 Hint

Consider how extra checks affect speed and safety.

Adding validation improves security but can slow down request processing, increasing latency.

❓ estimation

expert

Estimating Capacity for Entry and Exit Points

A system expects 10,000 requests per second. Each request requires 5ms processing at the entry point and 3ms at the exit point. How many entry and exit servers are needed to handle the load without queuing, assuming each server can process requests sequentially?

A Entry servers: 100, Exit servers: 60

B Entry servers: 50, Exit servers: 34

C Entry servers: 10, Exit servers: 5

D Entry servers: 20, Exit servers: 10

💡 Hint

Calculate how many requests one server can handle per second, then divide total requests by that number.

One entry server handles 1000ms / 5ms = 200 requests per second. For 10,000 requests, 10,000 / 200 = 50 servers needed. Similarly, exit servers handle 1000ms / 3ms ≈ 333 requests per second, so 10,000 / 333 ≈ 30.1, rounded up to 31 for safety.