XStreamCast: Broadcasting and Query Processing of Streamed XML Data

XStreamCast项目解决了连续流上xquery的高效处理，在连续流中，服务器并发地向多个客户机广播XML数据，客户机可以同时收听多个流。这个项目的目标是开发一个框架，提高所有客户端的查询吞吐量和响应时间，充分利用有限的资源。在这个框架下，XML流中的传输单元是XML片段，它对应于传输文档中的一个或几个XML元素。服务器可以选择在同一流中传播来自多个文档的XML片段，可以在关键或高需求时重复一些片段，可以通过发送增量更改来替换它们，并且可以删除无效的片段。客户机体系结构基于XQuery的优化框架，该框架利用许多有效的计算算法在内存和处理能力约束下处理XML数据流。最终目标是基于理论框架构建一个完整的原型系统，与其他流处理系统相比，该系统有望大幅提高性能。这个项目产生的算法和软件将对广泛的应用产生更广泛的影响，特别是在电子商务方面，因为它们将改进向客户提供服务的方式。它们还将减少服务器和客户端之间的网络流量，并将使小型服务提供商和企业能够使用功能较弱的服务器计算机和较低的网络成本为大量客户提供服务。项目网站（http://lambda.uta.edu/XStreamCast/）将提供访问研究结果和公共接口，以允许其他研究人员测试XQuery引擎。

The XStreamCast project addresses the efficient processing of XQueries over continuous streams in which a server broadcasts XML data to multiple clients concurrently and a client may tune-in to multiple streams at the same time. The goal of this project is to develop a framework that improves query throughput and response time on all clients, taking full advantage of their limited resources. Under this framework, the unit of transmission in an XML stream is an XML fragment, which corresponds to one or a few XML elements from the transmitted document. A server may choose to disseminate XML fragments from multiple documents in the same stream, can repeat some fragments when they are critical or in high demand, can replace them by sending delta changes, and can delete invalid ones. The client architecture is based on an optimization framework for XQuery that utilizes many efficient evaluation algorithms for processing XML data streams under memory and processing power constraints. The end goal is the construction of a complete prototype system based on the theoretical framework, which is expected to drastically improve performance when compared with other stream processing systems. The algorithms and the software resulting from this project will have a broader impact on a wide range of applications, especially in electronic commerce, since they will improve the way services are provided to clients. They will also reduce network traffic between servers and clients and will give the ability to small service providers and businesses to serve a larger number of clients using less powerful server computers and lower cost networking. The project Web site (http://lambda.uta.edu/XStreamCast/) will provide access research results and to a public interface to allow other researchers to test-drive the XQuery engine.