A Unified Peer-to-Peer Database Framework for Scalable Service and Resource Discovery

In a large distributed system spanning many administrative domains such as a Data Grid, it is desirable to maintain and query dynamic and timely information about active participants such as services, resources and user communities. However, in such a database system, the set of information tuples in the universe is partitioned over many distributed nodes, for reasons including autonomy, scalability, availability, performance and security. It is not obvious how to enable general-purpose discovery query support and collective collaborative functionality that operate on the distributed system as a whole, rather than on a given part of it. Further, it is not obvious how to allow for search results that are fresh, allowing dynamic content. It appears that a Peer-to-Peer (P2P) database network may be well suited to support dynamic distributed database search, for example for service discovery. In this paper, we devise the Unified Peer-to-Peer Database Framework (UPDF), which allows to express specific applications for arbitrary query languages (e.g. XQuery, SQL) and node topologies, and a wide range of data types, query response modes (e.g. Routed, Direct and Referral Response), neighbor selection policies, pipelining characteristics, timeout and other scope options

A BitTorrent-based peer-to-peer database server

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.EThOS - Electronic Theses Online ServiceGBUnited Kingdo