Exploiting templates to scale consistency maintenance in edge database caches
Khalil Amiri, Sara Sprenkle, Renu Tewari · 2003
Semantic database caching is a self-managing approach to dynamic materialization of "semantic" slices of back-end databases on servers at the edge of the network. It can be used to enhance the performance of distributed Web servers, information integration applications, and Web applications offloaded to edge servers. Such semantic caches often rely on update propagation protocols to maintain consistency with the back-end database system. However, the scalability of such update propagation protocols continues to be a major challenge. In this paper, we focus on the scalability of update propagation from back-end databases to the edge server caches. In particular, we propose a publish-subscribe like scheme for aggregating cache subscriptions at the back-end site to enhance the scalability of the filtering step required to route updates to the target caches. Our proposal exploits the template-rich nature of Web applications and promises significantly better scalability. In this paper, we describe our approach, discuss the tradeoffs that arise in its implementation, and estimate its scalability compared to naive update propagation schemes.