@CachePut for updating cache in Spring Boot - Performance & Optimization

Performance: @CachePut for updating cache

MEDIUM IMPACT

This affects server response time and memory usage by controlling how cache updates happen during method execution.

Updating cached data after a method changes the underlying data

Spring Boot

@CachePut(value = "items", key = "#item.id")
public Item updateItem(Item item) {
  // update logic
  return item;
}

Forces cache update after method runs, ensuring cache always has fresh data.

📈 Performance GainAvoids stale cache reads and extra DB calls, improving data consistency.

Updating cached data after a method changes the underlying data

Spring Boot

@Cacheable("items")
public Item updateItem(Item item) {
  // update logic
  return item;
}

Using @Cacheable only reads from cache and does not update it after changes, causing stale data.

📉 Performance CostCauses stale cache leading to inconsistent data and potential extra DB calls later.

Performance Comparison

Pattern	Method Execution	Cache Update	Data Freshness	Verdict
@Cacheable only	Skipped if cached	No update	Stale data possible	[X] Bad
@CachePut	Always runs	Updates cache after	Fresh data guaranteed	[OK] Good

Rendering Pipeline

When a method annotated with @CachePut runs, it executes fully and then updates the cache with the returned value. This avoids skipping method execution unlike @Cacheable.

→Method Execution

→Cache Update

⚠️ BottleneckCache Update stage can add latency if cache storage is slow or large data is stored.

Optimization Tips

1Use @CachePut when you need to update cache after method execution.

2Avoid using @CachePut for read-only methods to prevent unnecessary cache updates.

3Monitor cache update latency to keep server response times low.

Performance Quiz - 3 Questions

What is the main performance impact of using @CachePut in Spring Boot?

A It always executes the method and updates the cache, adding some latency.

B It skips method execution if cache exists, improving speed.

C It disables caching completely.

D It only reads from cache without updating.

DevTools: Spring Boot Actuator / Logs

How to check: Enable cache logging or use actuator endpoints to monitor cache hits and updates during method calls.

What to look for: Look for cache update logs confirming @CachePut triggers cache refresh after method execution.