Query evaluation techniques for large databases
ACM Computing Surveys (CSUR)
Towards estimation error guarantees for distinct values
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Algebraic XML Construction and its Optimization in Natix
World Wide Web
Performing Group-By before Join
Proceedings of the Tenth International Conference on Data Engineering
Including Group-By in Query Optimization
VLDB '94 Proceedings of the 20th International Conference on Very Large Data Bases
Aggregate-Query Processing in Data Warehousing Environments
VLDB '95 Proceedings of the 21th International Conference on Very Large Data Bases
EDBT '02 Proceedings of the Worshops XMLDM, MDDE, and YRWS on XML-Based Data Management and Multimedia Engineering-Revised Papers
Anatomy of a native XML base management system
The VLDB Journal — The International Journal on Very Large Data Bases
Extending XQuery for analytics
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
A Complete and Efficient Algebraic Compiler for XQuery
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
Strategies for query unnesting in XML databases
ACM Transactions on Database Systems (TODS)
Main memory implementations for binary grouping
XSym'05 Proceedings of the Third international conference on Database and XML Technologies
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Currently, grouping in XQuery must be expressed implicitly with nested FLWOR expressions. With XQuery 1.1, an explicit group by clause will be part of this query language. As users integrate this new construct into their applications, it becomes important to have efficient evaluation techniques available to process even complex grouping conditions. Among them, the removal of distinct values or distinct nodes in the partitions defined by the group by clause is not well-supported yet. The evaluation technique proposed in this paper is able to handle duplicate removal in the partitions efficiently. Experiments show the superiority of our solution compared to state-of-the-art query processing.