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Redis

Master Redis as the most popular in-memory data store for caching.

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Redis

Redis Data Types

Type Use Case
String Simple cache, counters
Hash Object fields
List Queues, recent items
Set Unique items, tags
Sorted Set Leaderboards, ranges

Spring Boot + Redis

@Service
public class CacheService {
    @Autowired
    private StringRedisTemplate redis;

    public void cache(String key, String value, Duration ttl) {
        redis.opsForValue().set(key, value, ttl);
    }

    public String get(String key) {
        return redis.opsForValue().get(key);
    }
}

Redis Patterns

Data Structures

Type Use Case
String Simple values, counters
Hash Objects, user profiles
List Queues, activity feeds
Set Tags, unique items
Sorted Set Leaderboards, time series

Best Practices

  • Use connection pooling
  • Set TTL for all keys
  • Monitor memory usage
  • Use pipelines for bulk operations

Common Patterns

  • Rate limiting with sliding window
  • Session storage
  • Pub/Sub for real-time updates

Key Points

  • Understanding Redis 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 Redis

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

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

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

Identify and handle edge cases for Redis. 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
Redis Testing Strategy

Write a testing strategy for Redis. 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. Redis is primarily?

Question 1 options

2. Redis default port?

Question 2 options

3. What is the primary purpose of Redis?

Question 3 options

4. What is a common mistake when implementing Redis?

Question 4 options

Flashcards

Question

Redis primary use?

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Answer

In-memory data store for caching

Question

Redis port?

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Answer

6379

Question

What is Redis?

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Answer

Redis is a key concept in backend development.

Question

When to use Redis?

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Answer

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

Question

Redis best practices

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Answer

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

Revision Notes

Key Takeaways

  • 1.Redis is in-memory data store
  • 2.Supports: String, Hash, List, Set, Sorted Set
  • 3.Spring: StringRedisTemplate or RedisTemplate
  • 4.Used for caching, sessions, queues

Interview Tips

  • •Use Redis for caching
  • •Know Redis data types

Cheat Sheet

Redis

  • In-memory data store
  • Types: String, Hash, List, Set, Sorted Set
  • Port: 6379
  • Spring: StringRedisTemplate