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Views in Peer-to-Peer: A platform for defining, indexing and exploiting XML views

ViP2P is a fully functional Java-based platform for the efficient, scalable management of XML documents in structured peer-to-peer networks based on distributed hash table (DHT) indices. We exploit indices (or materialized views) deployed in the P2P network independently by the peers, to answer an interesting dialect of tree pattern queries. There is a query (and view) language, a rewriting algorithm, view definition indexing strategies based on the DHT and much more…


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LiquidXML is built on top of ViP2P. Its main feature is to automatically select and continuously adapt the set of materialized views on each peer, to improve query processing performance both for the view holding peer, and for the other network peers. LiquidXML continuously adapts by adding more materialized views and/or replacing low-utility views with more useful ones according to the query workload.

In the figure below you can see the LiquidXML system in action. In this example, 4 peers participate in the network. The peers adapt their views to match the query workload. Views on each peer evolve in different adaptation time windows leading to lower response times. The system’s response time to queries converges in the last three adaptation time windows as the optimal set of views has been materialized.

More screenshots of the system can be found on this screenshots page. For more infromation concerning LiquidXML, you can contact Asterios Katsifodimos or Jesús Camacho-Rodríguez.

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