Efficient XQuery Join Processing in Publish/Subscribe Systems

Efficient XML filtering has been a fundamental technique in recent Web service and XML publish/subscribe applications. In this paper, we consider the problem of filtering a continuous stream of XML data against a large number of XQuery queries that contain multiple inter-document value-based join operations in their where clauses. To perform efficient join operations, the path expressions from these queries are extracted and organized in a way that multiple path expressions can be joined simultaneously. The join operations are then pipelined to minimize the number of join operations and to share any intermediate join results as much as possible. Our system operates on top of many currently available XPath filtering engines as an add-on module to extend their features to support queries with join operations. Experiments show that our proposal is efficient and scalable.

• Type: Conference
• Year: 2009
• Where: ADC
• Authors: Ryan H. Choi, Raymond K. Wong
• Keywords: ADC 2009, Database, Efficient Join Operations, Join Operations, Value-based Join Operations