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Summary: XSEED: Accurate and Fast Cardinality Estimation for XPath Queries
Ning Zhang M. Tamer ĻOzsu Ashraf Aboulnaga Ihab F. Ilyas
School of Computer Science, University of Waterloo
{nzhang, tozsu, ashraf, ilyas}@uwaterloo.ca
Abstract
We propose XSEED, a synopsis of path queries for
cardinality estimation that is accurate, robust, efficient, and
adaptive to memory budgets. XSEED starts from a very
small kernel, and then incrementally updates information
of the synopsis. With such an incremental construction, a
synopsis structure can be dynamically configured to accom-
modate different memory budgets. Cardinality estimation
based on XSEED can be performed very efficiently and
accurately. Extensive experiments on both synthetic and
real data sets show that even with less memory, XSEED
could achieve accuracy that is an order of magnitude better
than that of other synopsis structures. The cardinality
estimation time is under 2% of the actual querying time for
a wide range of queries in all test cases.
1 Introduction
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