Avoiding Unnecessary Ordering Operations in XPath

  • Jan Hidders
  • Philippe Michiels
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2921)


We present a sound and complete rule set for determining whether sorting by document order and duplicate removal operations in the query plan of XPath expressions are unnecessary. Additionally we define a deterministic automaton that illustrates how these rules can be translated into an efficient algorithm. This work is an important first step in the understanding and tackling of XPath/XQuery optimization problems that are related to ordering and duplicate removal.


Inference Rule Formal Semantic Query Plan Path Expression XPath Expression 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • Jan Hidders
    • 1
  • Philippe Michiels
    • 1
  1. 1.Dept. of Mathematics and Computer ScienceUniversity of AntwerpAntwerpenBelgium

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