XQPoint: A Queriable Homomorphic XML Compressor

XML has becoming the standard way for representing and transforming data over the World Wide Web. The annoying problem with XML documents is that they have a very high ratio of redundancy, which makes these documents storage demanding and require a large network band-width for transmission. To remedy this problem, a lot of approaches had been conducted in order to compress XML documents. Some of these approaches supply querying the compressed documents, while others compress the XML documents for archival purposes. In this paper we propose a new XML compression technique that obeys the structure of the XML documents and provides the ability to querying the compressed document with both content and structure (CAS) queries type. XML elements and attributes names are encoded by using fixed-point dictionary-based technique. Other XML data are organized into special containers according to their path from the root attribute, and the containers are compressed using the same fixed-point technique. Using different types of XML documents and different styles of user queries, the XQPoint has been experimented to test its effectiveness in both the compression ratio and the querying performance.