Content-based Dissemination of Fragmented XML Data

Content-based dissemination of data using pub/sub systems is an effective means to deliver relevant data to interested data consumers. With the emergence of XML as the standard for data representation and exchange, a lot of attention has been focused on pub/sub systems for XML-based dissemination, where subscriptions are specified using more expressive XML-based languages (e.g., XPath). In this paper, we address the problem of matching XPath-based subscriptions on fragmented XML data, which is motivated by both the prevalance of resource-constrained mobile devices for accessing/monitoring data as well as by the optimization opportunities from processing data in terms of fragments. We investigate efficient strategies to schedule and optimize the evaluation of XPath-based subscriptions on XML fragments. Our experimental results not only demonstrate the effectiveness of our proposed optimizations but also reveal several interesting performance tradeoffs.