Counting Relaxed Twig Matches in a Tree
نویسندگان
چکیده
We consider the problem of accurately estimating the number of approximate XML answers for a given query, and propose an efficient method that (1) accurately computes selectivity estimates for each relaxed XML query, using a natural generalization of the correlated subpath tree (CST) summary structure, and (2) carefully combines these estimates by analyzing the nature of overlap between the different relaxed twig queries.
منابع مشابه
Counting Twig Matches in a Tree
We describe efficient algorithms for accurately estimating the number of matches of a small node-labeled tree, i.e., a twig, in a large node-labeled tree, using a summary data structure. This problem is of interest for queries on XML and other hierarchical data, to provide query feedback and for costbased query optimization. Our summary data structure scalably representsapproximate frequency in...
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