Skipping Streams with XHints.
Akhil Gupta and Sudarshan S. Chawathe.
Technical Report CS-TR-4566 (UMIACS-TR-2004-11)
Computer Science Department, University of Maryland, College Park,
Maryland 20742. February 2004.
[ paper |
citation ]
When streaming semi-structured data is processed by a well-designed query processor, parsing constitutes a significant portion of the running time. Further improvements in performance therefore require some method to overcome the high cost of parsing. We have designed a general-purpose mechanism by which a producer of streaming data may augment the data stream with hints that permit a downstream processor to skip parsing parts of the stream. Inserting such hints requires additional processing by the producer of data; however, the resulting stream is more valuable to consumers, making such processing worthwhile. In this paper, we focus on hints that are designed to improve the throughput of a streaming XML query engine. We present a set of hint schemes and describe how a query engine can improve its performance by taking advantage of the hints. Finally, we demonstrate the benefits of our approach using an experimental study.