A BitTorrent-based peer-to-peer database server

Abstract

Database systems have traditionally used a Client-Server architecture, where clients send queries to a database server. If the data proves popular, the server may become overloaded, leading to clients experiencing an increase in query response time. In the domain of file-sharing, the problem of server overloading has been successfully addressed by the use of Peer-to-Peer (P2P) techniques in which users (peers) supply files – or pieces of files – to each other. This thesis will examine whether P2P techniques can be applied successfully in a database environment. It will introduce the Wigan Peer-to-Peer Database System, a P2P database system based on the popular BitTorrent file-sharing protocol. The potential benefits of a P2P database system include performance and scalability; allowing peers to answer each others’ queries will reduce the load on the database server and so could overcome the problem of a busy server becoming overloaded. Other potential benefits are fault tolerance and cost reduction. The Wigan architecture is introduced in this thesis, firstly by describing the BitTorrent algorithms and then by discussing how these algorithms must be modified for use in a database system. Experiments carried out on a simulator of Wigan are analysed in order to determine factors which affect its performance. These allow the identification of scenarios where Wigan could outperform a traditional database server. Further extensions to the Wigan architecture are discussed in this thesis, including possible means of handling data updates.