On supporting containment queries in relational database management systems
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
Holistic twig joins: optimal XML pattern matching
Proceedings of the 2002 ACM SIGMOD international conference on Management of data
Semantic Query Formulation and Evaluation for XML Databases
WISE '02 Proceedings of the 3rd International Conference on Web Information Systems Engineering
Structural Joins: A Primitive for Efficient XML Query Pattern Matching
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
Designing Semistructured Databases Using ORA-SS Model
WISE '01 Proceedings of the Second International Conference on Web Information Systems Engineering (WISE'01) Volume 1 - Volume 1
Accelerating XPath evaluation in any RDBMS
ACM Transactions on Database Systems (TODS)
On boosting holism in XML twig pattern matching using structural indexing techniques
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
From region encoding to extended dewey: on efficient processing of XML twig pattern matching
VLDB '05 Proceedings of the 31st international conference on Very large data bases
Towards Semantic Query Optimization for XML Databases
ICDEW '05 Proceedings of the 21st International Conference on Data Engineering Workshops
Twig2Stack: bottom-up processing of generalized-tree-pattern queries over XML documents
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Xpath on steroids: exploiting relational engines for xpath performance
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
Holistic twig joins on indexed XML documents
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
Using semantics in XML query processing
Proceedings of the 2nd international conference on Ubiquitous information management and communication
Optimizing XML twig queries in relational systems
Proceedings of the Fourteenth International Database Engineering & Applications Symposium
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Twig pattern matching (TPM) is the core operation of XML query processing. Existing approaches rely on either efficient data structures or novel labeling/indexing schemes to reduce the intermediate result size, but none of them takes into account the rich semantic information resided in XML document and the query issued. Moreover, in order to fulfill the semantics of the XPath/XQuery query, most of them require costly post processing to eliminate redundant matches and group matching results. In this paper, we propose an innovative semantics-aware query optimization approach to overcome these limitations. In particular, we exploit the functional dependency derived from the given semantic information to stop query processing early; we distinguish the output and predicate nodes of a query, then propose a query breakup technique and build a query plan, such that for each distinct query output, we avoid finding the redundant matches having the same results as the first match in most cases. Both I/O and structural join cost are saved, and much less intermediate results are produced. Experiments show the effectiveness of our optimization.