Semantic Query Routing and Distributed Top-k Query Processing in Peer-to-Peer Networks
Ioannis Chrysakis, Dimitris Plexousakis, Vassilika Vouton · 2006
Requirements for widely distributed information systems supporting virtual organizations have given rise to a new category of peer-to-peer (p2p) systems called schema-based. In such systems each peer is a database management system in itself, exposing its own schema. In such a setting, a main objective is the efficient search across peer databases by processing each incoming query without overly consuming bandwidth. In this report, we adopt a super-peer-based architecture and suggest a query routing mechanism, upon which we propose a query processing technique for top-k queries. Top-k queries in the context of p2p systems give the opportunity to filter the results and to eliminate network traffic by choosing the k highest ranked results. We introduce HT-p2p and HT-p2p+, two extended versions of the Hybrid Threshold Algorithm adapted to our p2p scenario. For the evaluation of these algorithms we implemented a prototype system upon the JXTA platform. Extensive experiments with different data sets and parameters have shown promising results about the performance of the query processing strategy. ± Acknowledgement: Special thanks to Evi Dagalaki for her contribution to the evaluation process. 1