Cachematic - Automatic Invalidation in Application-Level Caching Systems

Abstract

Caching is a common method for improving the performance of modern web applications. Due to the varying architecture of web applications, and the lack of a standardized approach to cache management, ad-hoc solutions are common. These solutions tend to be hard to maintain as a code base grows, and are a common source of bugs. We present Cachematic, a general purpose application-level caching system with an au- tomatic cache management strategy. Cachematic provides a simple programming model, allowing developers to explic- itly denote a function as cacheable. The result of a cacheable function will transparently be cached without the developer having to worry about cache management. We present algo- rithms that automatically handle cache management, han- dling the cache dependency tree, and cache invalidation. Our experiments showed that the deployment of Cachematic decreased response time for read requests, compared to a manual cache management strategy for a representative case study conducted in collaboration with Bison, an US-based business intelligence company. We also found that, com- pared to the manual strategy, the cache hit rate was in- creased with a factor of around 1.64x. However, we observe a significant increase in response time for write requests. We conclude that automatic cache management as implemented in Cachematic is attractive for read-domminant use cases, but the substantial write overhead in our current proof-of- concept implementation represents a challenge.