P2P-Join: A Keyword Based Join Operation in Relational Database Enabled Peer-to-Peer Systems

Query-by-keywords is the most popular manner to search for data in this computing age. However, most work was proposed for searching centralized relational databases. This paper investigates how keyword search is to be deployed in relational database-enabled peer-to-peer systems. Unlike centralized system, the key challenges in this new computing paradigm come from the autonomy of peers, the lack of a global schema, and the dynamics of the peer connectivity. First, the concept of P2P-join is proposed, which is a join operation to combine tuples among relations from different peers containing certain keywords in the query. Second, a fully distributed framework to realize P2P-join processing is devised, which not only inherits the syntax and semantics of traditional join but also cherishes the ideology of peer-to-peer computing. Finally, two mechanisms are proposed to improve the performance of the operation: a join path selecting order scheme and a push-based load balancing mechanism across peers