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ICDE
2007
IEEE

Structural Selectivity Estimation for XML Documents

10 years 9 months ago
Structural Selectivity Estimation for XML Documents
Estimating the selectivity of queries is a crucial problem in database systems. Virtually all database systems rely on the use of selectivity estimates to choose amongst the many possible execution plans for a particular query. In terms of XML databases, the problem of selectivity estimation of queries presents new challenges: many evaluation operators are possible, such as simple navigation, structural joins, or twig joins, and many different indexes are possible ranging from traditional B-trees to complicated XML-specific graph indexes. A new synopsis for XML documents is introduced which can be effectively used to estimate the selectivity of complex path queries. The synopsis is based on a lossy compression of the document tree that underlies the XML document, and can be computed in one pass from the document. It has several advantages over existing approaches: (1) it allows one to estimate the selectivity of queries containing all XPath axes, including the order-sensitive ones, (2...
Damien K. Fisher, Sebastian Maneth
Added 01 Nov 2009
Updated 01 Nov 2009
Type Conference
Year 2007
Where ICDE
Authors Damien K. Fisher, Sebastian Maneth
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