Redis as cache provider in Spring Boot - Performance & Optimization

Performance: Redis as cache provider

HIGH IMPACT

This affects page load speed by reducing backend response time and lowering server load through fast data retrieval.

Caching frequently accessed data to speed up response

Spring Boot

public String getData(String key) {
  String cached = redis.get(key);
  if (cached != null) return cached;
  String data = database.query(key);
  redis.set(key, data);
  return data;
}

Data is served from Redis cache if available, avoiding slow database calls.

📈 Performance GainReduces backend response time by 50-90%, improving LCP

Caching frequently accessed data to speed up response

Spring Boot

public String getData(String key) {
  // No caching, always fetch from database
  return database.query(key);
}

Every request hits the database causing slow responses and high server load.

📉 Performance CostBlocks rendering for 100+ ms per request depending on DB speed

Performance Comparison

Pattern	DOM Operations	Reflows	Paint Cost	Verdict
No cache, direct DB calls	N/A	N/A	High backend delay delays paint	[X] Bad
Redis cache for frequent data	N/A	N/A	Fast backend response speeds paint	[OK] Good

Rendering Pipeline

Using Redis cache shortens backend processing time, allowing the server to send data faster to the browser, which speeds up the critical rendering path.

→Backend Processing

→Network Transfer

→First Paint

⚠️ BottleneckBackend Processing when database queries are slow

Core Web Vital Affected

LCP

This affects page load speed by reducing backend response time and lowering server load through fast data retrieval.

Optimization Tips

1Cache frequently accessed data in Redis to reduce backend response time.

2Avoid cache misses by pre-warming Redis with common queries.

3Monitor cache hit ratio to ensure Redis is effectively improving performance.

Performance Quiz - 3 Questions

How does using Redis as a cache provider affect Largest Contentful Paint (LCP)?

A It reduces LCP by serving data faster from cache.

B It increases LCP by adding extra network calls.

C It has no effect on LCP.

D It only affects Cumulative Layout Shift (CLS).

DevTools: Network

How to check: Open DevTools > Network tab, reload page, check response times for API calls.

What to look for: Look for reduced response times on repeated requests indicating cache hits.