Skip to content
intermediatePhase ·

Latency

Measure and optimize response latency in backend systems.

35m
0 problems
Topic Progress0%

Latency

What Is Latency?

Time for a request to travel and get a response.

Client → Network (50ms) → Server (100ms) → Network (50ms) → Client
Total latency: 200ms

Latency Sources

Source Typical
Network RTT 10-200ms
DNS 1-50ms
TLS handshake 1-2 round trips
Server processing 1-1000ms+

Key Points

  • Understanding Latency is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

Latency Optimization

Components

  • Network: Round-trip time
  • Processing: Computation
  • Queueing: Wait time
  • Serialization: Encode/decode

Optimization

  • Caching
  • CDN
  • Connection pooling
  • Compression

Measurement

p50: 50ms
p95: 200ms
p99: 500ms

Best Practices

  • Set latency budgets
  • Monitor percentiles
  • Optimize hot paths

Key Points

  • Understanding Latency is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

Practice Problems

0/3solved
Implement Latency

Design and implement a solution for Latency in a backend system. Consider scalability, error handling, and production readiness.

Solution
// Latency implementation
// Key aspects: validation, error handling, logging, testing

public class Latency {
    // Production-ready implementation
}
Latency Edge Cases

Identify and handle edge cases for Latency. What happens under high load, with invalid input, or during failures?

Solution
// Edge case handling:
// 1. Null/empty input -> validation
// 2. High load -> rate limiting, queuing
// 3. Failures -> retries, circuit breaker
// 4. Concurrent access -> locks, idempotency
Latency Testing Strategy

Write a testing strategy for Latency. Include unit tests, integration tests, and performance tests.

Solution
// Test plan:
// - Unit: 80% coverage target
// - Integration: API contracts
// - Performance: latency, throughput
// - Chaos: failure injection

Quiz

1. Latency is?

Question 1 options

2. Network RTT stands for?

Question 2 options

3. What is the primary purpose of Latency?

Question 3 options

4. What is a common mistake when implementing Latency?

Question 4 options

Flashcards

Question

Latency?

Click to reveal answer

Answer

Time for request to travel and return

Question

RTT?

Click to reveal answer

Answer

Round-Trip Time

Question

What is Latency?

Click to reveal answer

Answer

Latency is a key concept in backend development.

Question

When to use Latency?

Click to reveal answer

Answer

Use Latency when building production systems that require reliability, scalability, and maintainability.

Question

Latency best practices

Click to reveal answer

Answer

Follow SOLID principles, write clean code, test thoroughly, document decisions, and monitor in production.

Revision Notes

Key Takeaways

  • 1.Latency = time for request round trip
  • 2.Sources: network, DNS, TLS, processing
  • 3.Reduce: CDN, keep-alive, connection pooling

Interview Tips

  • •Measure and reduce latency
  • •Know latency sources

Cheat Sheet

Latency

  • Time for request to travel and return
  • Sources: network, DNS, TLS, server
  • Reduce: CDN, keep-alive, pooling