An Evaluation of Regular Path Expressions with Qualifiers against XML Streams

This paper presents SPEX, a streamed and progressive evaluation of regular path expressions with XPath-like qualifiers against XML streams. SPEX proceeds as follows. An expression is translated in linear time into a network of transducers, most of them having 1-DPDT equivalents. Every stream message is then processed once by the entire network and result fragments are output on the fly. In most practical cases SPEX needs a time linear in the stream size and for transducer stacks a memory quadratic in the stream depth. Experiments with a prototype implementation point to a very good efficiency of the SPEX approach. 1 Motivation Querying data streams is motivated by applications like real time measurements and continuous services which select informations from continuous streams of data, e.g. stock exchange or meteorology data. For a selective dissemination of information, streams have to be filtered according to complex queries before being distributed to subscribers [2]. To integrate ...

• Type: Conference
• Year: 2003
• Where: ICDE
• Authors: Dan Olteanu, François Bry, Tobias Kiesling
• Keywords: Data Streams, Database, ICDE 2003, Regular Path Expressions, Wellformed Xml Streams