Caching for Improved Response Times in a Distributed System

To cope with slow response times that emerge in data-centric web applications, caching can be used to avoid unnecessary database queries and recalculations. Slow response times become prevalent when using Insights — a tool that gathers data from continuously expanding databases and summarizes it into statistical information. Insights has a master-slave system architecture, composed of one central server and a number of distributed servers with accompanying databases. A solution that entails caching server responses in each of the distributed servers is proposed, and a prototype is developed. The cache is filled both by computing responses for common requests in advance and by dynamically updating the cache. Randomized tests that simulate expected access patterns show that the prototype has a better average hit ratio than a purely dynamic cache and a notably improved response time compared to having no cache, rendering it a promising cache design to appropriate in the Insights system