Data Sharing in P2P Systems

In this chapter, we survey P2P data sharing systems. All along, we focus on the evolution from simple file-sharing systems, with limited functionalities, to Peer Data Management Systems (PDMS) that support advanced applications with more sophisticated data management techniques. Advanced P2P applications are dealing with semantically rich data (e.g. XML documents, relational tables), using a high-level SQL-like query language. We start our survey with an overview over the existing P2P network architectures, and the associated routing protocols. Then, we discuss data indexing techniques based on their distribution degree and the semantics they can capture from the underlying data. We also discuss schema management techniques which allow integrating heterogeneous data. We conclude by discussing the techniques proposed for processing complex queries (e.g. range and join queries). Complex query facilities are necessary for advanced applications which require a high level of search expressiveness. This last part shows the lack of querying techniques that allow for an approximate query answering. Rabab Hayek LINA, 2 rue de la Houssiniere 44322 Nantes France, e-mail: [email protected] Guillaume Raschia LINA, 2 rue de la Houssiniere 44322 Nantes France, e-mail: [email protected] Patrick Valduriez INRIA, 2 rue de la Houssiniere 44322 Nantes France, e-mail: [email protected] Noureddine Mouaddib LINA, 2 rue de la Houssiniere 44322 Nantes France, e-mail: [email protected] 1 ha l-0 03 79 83 2, v er si on 1 29 A pr 2 00 9 2 Rabab Hayek and Guillaume Raschia and Patrick Valduriez and Noureddine Mouaddib