DBCache: Database Caching For Web Application Servers

Abstract

Many e-Business applications today are being developed and deployed on multi-tier environments involving browser-based clients, web application servers and backend databases. The dynamic nature of these applications necessitates generating web pages on-demand, making middle-tier database caching an effective approach to achieve high scalability and performance [3]. In the DBCache project, we are incorporating a database cache feature in DB2 UDB by modifying the engine code and leveraging existing federated database functionality. This allows us to take advantage of DB2's sophisticated distributed query processing power for database caching. As a result, the user queries can be executed at either the local database cache or the remote backend server, or more importantly, the query can be partitioned and then distributed to both databases for cost optimum execution.DBCache also includes a cache initialization component that takes a backend database schema and SQL queries in the workload, and generates a middle-tier database schema for the cache. We have implemented an initial prototype of the system that supports table level caching. As DB2's functionality is extended, we will be able to support subtable level caching, XML data caching and caching of execution results of web services.