StatiX++: Flexible XML Statistics Gathering and XML Query Cardinality Estimation

Introduction

A key component of XML data management systems is the result size estimator, which estimates the cardinalities of user queries. Estimated cardinalities are needed in a variety of tasks, including query optimization and cost-based storage design; and they can also be used to give users early feedback about the expected outcome of their queries.

StatiX++ is a framework that gathers XML statistics and estimates XML query cardinality with flexibilities. StatiX++ uses and histograms to uniformly capture both the structural and value skew present in documents. In particular, StatiX++ exploits schema information and schema transformation technology to produce optimized high-quality and concise statistical summaries, as well as accurate query cardinality estimation.

Important Features

Support for recursive schemata
Support for ambiguous schemata that result from schema transformations
Techniques to further compress the statistical summaries
Efficient statistics gathering---ability to handle very large XML documents

Publications

IMAX: Incremental Maintenance of Schema-Based XML Statistics

(by Maya Ramanath, Lingzhi Zhang, Juliana Freire and Jayant Haritsa)

In Proceedings of ICDE, 2005.
A Flexible Infrastructure for Gathering XML Statistics and Estimating Query Cardinality

(by Juliana Freire, Maya Ramanath, and Lingzhi Zhang )

Demo in Proceedings of ICDE, 2004.
StatiX: Making XML Count (pdf version)
(by Juliana Freire, Jayant Haritsa, Maya Ramanath, Prasan Roy and Jerome Simeon)

Proceedings of SIGMOD 2002.

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People

Juliana Freire
Jayant Haritsa
Maya Ramanath
Lingzhi Zhang
Radhika Bheemidi

This project is currently funded by the National Science Foundation grant number IIS-0534628.

Juliana Freire

Last modified: Tue Feb 7 13:41:22 PST 2006