Fractional XSketch Synopses for XML Databases

11 years 10 months ago
Fractional XSketch Synopses for XML Databases
A key step in the optimization of declarative queries over XML data is estimating the selectivity of path expressions, i.e., the number of elements reached by a specific navigation pattern through the XML data graph. Recent studies have introduced XSketch structural graph synopses as an effective, space-efficient tool for the compile-time estimation of complex path-expression selectivities over graph-structured, schema-less XML data. Briefly, XSketches exploit localized graph stability and well-founded statistical assumptions to accurately approximate the path and branching distribution in the underlying XML data graph. Empirical results have demonstrated the effectiveness of XSketch summaries over real-life and synthetic data sets, and for a variety of path-expression workloads. In this paper, we introduce fractional XSketches (fXSketches) a simple, yet intuitive and very effective generalization of the basic XSketch summarization mechanism. In a nutshell, our fXSketch synopsis ext...
Natasha Drukh, Neoklis Polyzotis, Minos N. Garofal
Added 03 Jul 2010
Updated 03 Jul 2010
Type Conference
Year 2004
Where XSYM
Authors Natasha Drukh, Neoklis Polyzotis, Minos N. Garofalakis, Yossi Matias
Comments (0)