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Article
Continuous Monitoring of Top-K Queries over Sliding Windows
SIGMOD 2006: Proceedings of the 2006 ACM SIGMOD International Conference on Management of Data: Chicago, Illinois, USA, June 26-29, 2006
  • Kyriakos MOURATIDIS, Singapore Management University
  • Spiridon BAKIRAS, Hong Kong University of Science and Technology
  • Dimitris PAPADIAS, Hong Kong University of Science and Technology
Publication Type
Conference Proceeding Article
Version
publishedVersion
Publication Date
7-2007
Abstract

Given a dataset P and a preference function f, a top-k query retrieves the k tuples in P with the highest scores according to f. Even though the problem is well-studied in conventional databases, the existing methods are inapplicable to highly dynamic environments involving numerous long-running queries. This paper studies continuous monitoring of top-k queries over a fixed-size window W of the most recent data. The window size can be expressed either in terms of the number of active tuples or time units. We propose a general methodology for top-k monitoring that restricts processing to the sub-domains of the workspace that influence the result of some query. To cope with high stream rates and provide fast answers in an on-line fashion, the data in W reside in main memory. The valid records are indexed by a grid structure, which also maintains book-keeping information. We present two processing techniques: the first one computes the new answer of a query whenever some of the current top-k points expire; the second one partially pre-computes the future changes in the result, achieving better running time at the expense of slightly higher space requirements. We analyze the performance of both algorithms and evaluate their efficiency through extensive experiments. Finally, we extend the proposed framework to other query types and a different data stream model.

Keywords
  • dataset,
  • continuous monitoring,
  • processing techniques,
  • algorithm performance
ISBN
9781595934345
Identifier
10.1145/1142473.1142544
Publisher
ACM
City or Country
New York
Creative Commons License
Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International
Additional URL
http://dx.doi.org/10.1145/1142473.1142544
Citation Information
Kyriakos MOURATIDIS, Spiridon BAKIRAS and Dimitris PAPADIAS. "Continuous Monitoring of Top-K Queries over Sliding Windows" SIGMOD 2006: Proceedings of the 2006 ACM SIGMOD International Conference on Management of Data: Chicago, Illinois, USA, June 26-29, 2006 (2007) p. 635 - 646
Available at: http://works.bepress.com/kyriakos_mouratidis/4/