The New HybridCache Has a BIG Problem!

Milan Jovanović explains why .NET 9's HybridCache fails to propagate cache invalidation across multiple nodes and demonstrates a Redis Pub/Sub fix.

Want to master Clean Architecture? Go here: bit.ly/3PupkOJ Want to unlock Modular Monoliths? Go here: bit.ly/3SXlzSt Get the source code here: patreon.com/milanjovanovic In this video, I reveal a critical issue with the newly released stable version of HybridCache library and demonstrate how to fix it. The problem occurs in multi-node environments where cache invalidation fails to propagate to all instances. What you'll learn: - Why HybridCache doesn't work properly in distributed systems - How cache invalidation only affects the current node and level 2 cache (Redis) - Step-by-step implementation of a Redis Pub/Sub solution to synchronize cache invalidation - Creating a background service to listen for cache invalidation events - Alternative solutions if you prefer not to implement this yourself I demonstrate the issue using a clear diagram showing how when one server invalidates a cache entry, the other servers' level 1 caches still contain stale data. The solution leverages Redis' publish/subscribe mechanism to broadcast invalidation messages to all application nodes. If you don't want to implement this yourself, you can either: 1. Set a very short local cache expiration time in HybridCache configuration 2. Use FusionCache as an alternative with its built-in Redis backplane support Complete with code samples and a demonstration using multiple application instances with .NET Aspire. Check out my courses: milanjovanovic.tech/courses Read my Blog here: milanjovanovic.tech/blog Join my weekly .NET newsletter: milanjovanovic.tech Chapters 0:00 HybridCache: The Problem 1:45 Drawing some boxes 4:44 Solving the problem - Option 1 5:25 Solving the problem - Option 2 (FusionCache) 5:53 Solving the problem - Option 3 (Channels)