Section: New Results

XML Warehousing in P2P

Participants : Serge Abiteboul, Jesùs Camacho-Rodriguez, Ioana Manolescu, Konstantinos Karanasos, Asterios Katsifodimos, Alin Tilea, Spyros Zoupanos.

XML materialized views in P2P

This activity has strongly picked up in volume of work and in the number of people involved. Significant prototyping and experimentation was carried on within the VIP2P project (http://vip2p.saclay.inria.fr ). ViP2P allows wide-scale sharing of XML documents based on a distributed hash table (or DHT). VIP2P peers independently publish (share) XML documents that others may query. Moreover, each peer may choose to materialize a given set of views, described by XML tree patterns. A query posed in the network of peers is thus first rewritten with the help of the views available in the network, then executed by exploiting these views [38] , [39] .

Many developments are ongoing around the ViP2P platform, as part of the ANR CODEX project. First, we consider the extension of the platform to handle XML documents with RDF annotations. The problem is much more complex than when considering XML documents only, since it requires detecting distributed value joins over XML tree pattern queries. Our approach to solve it is described in a technical report [49] . Second, we started to tackle the issue of adapting the materialized views in the ViP2P network to the needs (queries) issued by the various peers [50] .

P2P XML indexing

We have pursued the work on the ViP2P peer-to-peer platform for building and managing warehouses of Web resources. Our previous work addressed the issue of indexing extensional XML data (trees). We are currently working on indexing also graph data, more precisely, XML documents with references to other documents or including function calls.