An Internet-Scale Service for Publishing and Locating XML Documents

In recent years, there has been a growing interest for peer-to-peer (P2P) based computing and applications. One of the most important challenges in P2P environments is to quickly locate relevant data across many participating peers. In this demonstration, we present psiX, which is an Internet-scale service for publishing and locating XML documents. This service runs on several PlanetLab nodes geographically spread across the globe. The psiX system adopts a suite of new techniques for XML indexing and pattern matching in a P2P network, namely, (a) representing XML documents and XPath queries compactly via algebraic signatures, (b) searching signatures of documents and value summaries indexed using distributed hierarchical indexes built over a Distributed Hash Table (DHT), and (c) gracefully adapting to failures while running on the Internet, where failures are a norm rather than an exception.