Caching is hard | The Backend Engineering Show

This episode explores the complexities of caching in backend engineering, using a Forem article as a case study. Against the backdrop of the common adage that "cache invalidation and naming things are the two hard problems in computer science," the host delves into the three levels of caching—edge caching, Rails caching, and database caching—employed by Forem. More significantly, the discussion highlights the challenges of cache invalidation, illustrating how outdated attributes in database tables can persist despite invalidating higher-level caches. For instance, a bug involving an organization's image not updating across all cached articles is examined. The host cautions against using caching as a quick fix for performance issues, emphasizing the importance of understanding the root cause of slow queries before implementing caching strategies. Ultimately, the episode underscores the need for a thorough understanding of caching mechanisms and their potential pitfalls to avoid unnecessary complexity and ensure efficient application performance.