Query processing of multi-way stream window joins

Moustafa A. Hammad, Walid G. Aref, Ahmed Elmagarmid

Research output: Contribution to journalArticle

10 Citations (Scopus)


This paper introduces a class of join algorithms, termed W-join, for joining multiple infinite data streams. W-join addresses the infinite nature of the data streams by joining stream data items that lie within a sliding window and that match a certain join condition. In addition to its general applicability in stream query processing, W-join can be used to track the motion of a moving object or detect the propagation of clouds of hazardous material or pollution spills over time in a sensor network environment. We describe two new algorithms for W-join and address variations and local/global optimizations related to specifying the nature of the window constraints to fulfill the posed queries. The performance of the proposed algorithms is studied experimentally in a prototype stream database system, using synthetic data streams and real time-series data. Tradeoffs of the proposed algorithms and their advantages and disadvantages are highlighted, given variations in the aggregate arrival rates of the input data streams and the desired response times per query.

Original languageEnglish
Pages (from-to)469-488
Number of pages20
JournalVLDB Journal
Issue number3
Publication statusPublished - 1 May 2008
Externally publishedYes



  • Multi-way window join
  • Stream query processing

ASJC Scopus subject areas

  • Hardware and Architecture
  • Information Systems

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