P2P XQuery and the StreetTiVo application

In the AmbientDB project, we are building MonetDB/XQuery, an open-source XML DBMS (XDBMS) with support for distributed querying and P2P services. Our work is motivated by the hypothesis that P2P is a disruptive paradigm that should change the nature of database technology. Most of the existing distributed DBMS technologies were developed to be used in (small-scale) local-area networks (LAN). Those technologies usually assume that (i) there is a central controller and/or peers have complete knowledge of the whole system, (ii) peers are uniform and highly available, (iii) placement of data happens in a controlled way and is rarely changed and (iv) a global database schema is used. Peer-to-Peer (P2P) networks have led the distributed DBMS research to reconsider existing technologies in such a new environment, where (i) systems have decentralized architectures, (ii) peers join or leave the network at any time, (iii) placement of data is out of the system's control and it changes frequently, (iv) each peer can have its local database schema (or no schema at all), and (v) data owned by the peers are often incomplete, overlapping and even conflicting.