spring-redis-performance

Redis Cache-aside: Student GET 85ms DB → 2ms Redis | Java 17 + Spring Boot 2.6.6

Backend service proving Redis caching with measurable performance gains.

🚀 Tech Stack

Layer	Technology
Backend	Java 17, Spring Boot 2.6.6, Spring Web, Spring Data JPA
Cache	Redis with Jackson JSON + @Cacheable
Database	H2 in-memory for dev/testing
Ops	Docker Compose, Timing logs

⚡ Performance Proof

Before Redis: Student GET 85ms DB query
After Redis: Student GET 2ms cache hit
Speedup: 42.5x faster with @Cacheable on service layer
Proof method: System.currentTimeMillis logs in console

🛠️ Redis Implementation

@Cacheable(value = "student-cache", key = "#id")
@Transactional(readOnly = true) 
public Student getstudentById(Long id) {
    long start = System.currentTimeMillis();
    Student student = studentRepository.findById(id).orElse(null);
    System.out.println("DB hit for ID " + id + ": " + (System.currentTimeMillis() - start) + "ms");
    return student;
}
🏗️ Run Locally
bash
docker compose up -d
mvn spring-boot:run
App: http://localhost:8080