A Novel Top-k Query Scheme in Unstructured P2P Networks

There're two major problems in the unstructured p2p systems, one is their heavy network traffic; the other is the problem of query effectiveness, which is caused mainly by high numbers of query answers, many of which are irrelevant for users. A potential solution is to use Top-k queries. The objective of a top-k query is to find the k highest ranked answers to the user defined similarity function. Top-k query is widely used in the search engine and gains great success. However, processing top-k query in unstructured p2p network is very challenging because a p2p system is a dynamic and decentralized system. In this paper we present HPJT, a novel P2p Hierarchical Join Top-k query scheme. A fully distributed query processing algorithm for top-k query is proposed, of which the key idea is `put computation to the network'. The simulation results indicate that HPJT shows good performance.