Abstract
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.
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Hidders, J., Michiels, P. (2004). Avoiding Unnecessary Ordering Operations in XPath. In: Lausen, G., Suciu, D. (eds) Database Programming Languages. DBPL 2003. Lecture Notes in Computer Science, vol 2921. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-24607-7_5
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DOI: https://doi.org/10.1007/978-3-540-24607-7_5
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