Stream Operators for Querying Data Streams

Lisha Ma, Stratis D. Viglas, Meng Li, Qian Li

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract / Description of output

One of the most important uses of aggregate queries over data streams is sampling. Typically, aggregation is performed over sliding windows where queries return new results whenever the window contents change, a concept referred to as a continuous query. Existing data models and query languages for streams are not capable of expressing many practical user-defined samplings over streams. To this end we propose a new data stream model, referred to as the sequence model, and a query language for specifying aggregate queries over data streams. We show that the sequence model can readily express a superset of the aggregate queries expressible in the previously proposed time-based data stream model, thus providing a declarative and formal semantics to understand and reason about continuous aggregate queries. Defined on top of the sequence model, our query language supports existing sliding window operators and a novel frequency operator. By using the frequency operator one is capable of expressing useful sampling queries, such as queries with user-defined group-based sampling and nested aggregation over either the input stream or the result stream. Such capabilities are beyond those of previously proposed query languages over streams. Finally, we conduct a preliminary experimental study that shows our language is effective and efficient in practice.
Original languageEnglish
Title of host publicationAdvances in Web-Age Information Management
Subtitle of host publication6th International Conference, WAIM 2005, Hangzhou, China, October 11 – 13, 2005. Proceedings
EditorsWenfei Fan, Zhaohui Wu, Jun Yang
Place of PublicationBerlin, Heidelberg
PublisherSpringer Berlin Heidelberg
Number of pages12
ISBN (Electronic)978-3-540-32087-6
ISBN (Print)978-3-540-29227-2
Publication statusPublished - 2005

Publication series

NameLecture Notes in Computer Science
PublisherSpringer Berlin Heidelberg
ISSN (Print)0302-9743


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