juniorCaching
What is Cache Invalidation?
Updated Apr 28, 2026
Short answer
The process of declaring cached data as stale or invalid when the original data changes.
Deep explanation
Caching is essential for performance optimization. The process of declaring cached data as stale or invalid when the original data changes. By reducing the need to access slower storage layers (like HDDs or remote databases), systems can achieve much lower latency.
Real-world example
Storing the results of a complex database query in Redis.
Common mistakes
- Not setting a TTL, leading to the cache growing indefinitely or serving very old data.
Follow-up questions
- Is cache persistent?