Cache-Aware Query Routing in a Cluster of Databases
|Title||Cache-Aware Query Routing in a Cluster of Databases|
|Author(s)||U. Röhm, K. Böhm, H.-J. Schek|
|Booktitle||Proceedings of the 17th International Conference on Data Engineering (ICDE2001)Heidelberg, Germany|
AbstractWe investigate query routing techniques in a cluster of databases for a query-dominant environment. The objective is to decrease query response time. Each component of the cluster runs an off-the-shelf DBMS and holds a copy of the whole database. The cluster has a coordinator that routes each query to an appropriate component. Considering queries of realistic complexity, e.g., TPC-R, this article addresses the following questions: Can routing benefit from caching effects due to previous queries? Since our components are black-boxes, how can we approximate their cache content? How to route a query, given such cache approximations? To answer these questions, we have developed a cache-aware query router that is based on signature approximations of queries. We report on experimental evaluations with the TPC-R benchmark using our PowerDB database cluster prototype. Our main result is that our approach of cache approximation routing is better than state-of-the-art strategies by a factor of two with regard to mean response time.