Enterprise Redis Caching Strategies: Cache-Aside, Write-Through & Cache Invalidation

Caching reduces database load and delivers sub-millisecond API responses. Learn how to implement Cache-Aside, handle Cache Stampede (Thundering Herd) with distributed locks, and configure Redis Cluster Sentinel failover.

1. Cache-Aside Pattern Implementation

public UserDto getUserById(Long userId) {
    String cacheKey = "user:" + userId;
    
    // 1. Try Redis Cache Hit
    UserDto cachedUser = redisTemplate.opsForValue().get(cacheKey);
    if (cachedUser != null) {
        return cachedUser; // Sub-2ms response
    }
    
    // 2. Cache Miss: Query Database (150ms)
    UserDto dbUser = userRepository.findById(userId)
            .map(this::convertToDto)
            .orElseThrow(() -> new ResourceNotFoundException("User not found"));
            
    // 3. Populate Redis Cache with 1-hour TTL
    redisTemplate.opsForValue().set(cacheKey, dbUser, Duration.ofHours(1));
    return dbUser;
}

2. Related Architecture Resources

• ⚡ System Design & Architecture Patterns (5 Interactive Animations)