Foreseer: A novel, locality-aware peer-to-peer system architecture for keyword searches

Abstract

Peer-to-peer (P2P) systems are becoming increasingly popular and complex, serving millions of users today. However, the design of current unstructured P2P systems does not take full advantage of rich locality properties present in P2P system workloads, thus possibly resulting in inefficient searches or poor system scalability. In this paper, we propose a novel locality-aware P2P system architecture called Foreseer, which explicitly exploits geographical locality and temporal locality by constructing a neighbor overlay and a friend overlay respectively. Each peer in Foreseer maintains a small number of neighbors and friends along with their content filters used as distributed indices. By combining the advantages of distributed indices and utilization of two-dimensional localities, the Foreseer search scheme satisfies more than 99% of keyword search queries and realizes very high search performance, with a low maintenance cost. In addition, query messages rarely touch free-riders, and therefore avoid most meaningless messages inherent in unstructured P2P systems. Our simulation results show that, compared with current unstructured P2P systems, Foreseer boosts search efficiency while adding only modest maintenance costs. © IFIP International Federation for Information Processing 2004.