Fundamental techniques for order optimization
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Database Systems Concepts
Bringing order to query optimization
ACM SIGMOD Record
Access path selection in a relational database management system
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
The Implementation of POSTGRES
IEEE Transactions on Knowledge and Data Engineering
Performing Group-By before Join
Proceedings of the Tenth International Conference on Data Engineering
Hashing Methods and Relational Algebra Operations
VLDB '84 Proceedings of the 10th International Conference on Very Large Data Bases
Including Group-By in Query Optimization
VLDB '94 Proceedings of the 20th International Conference on Very Large Data Bases
Exploiting early sorting and early partitioning for decision support query processing
The VLDB Journal — The International Journal on Very Large Data Bases
MonetDB/XQuery: a fast XQuery processor powered by a relational engine
Proceedings of the 2006 ACM SIGMOD international conference on Management of data
A combined framework for grouping and order optimization
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
Deciding the physical implementation of ETL workflows
Proceedings of the ACM tenth international workshop on Data warehousing and OLAP
Isolating order semantics in order-sensitive xquery-to-SQL translation
BNCOD'07 Proceedings of the 24th British national conference on Databases
Fast sorting on flash memory sensor nodes
Proceedings of the Fourteenth International Database Engineering & Applications Symposium
Which sort orders are interesting?
The VLDB Journal — The International Journal on Very Large Data Bases
Advanced partitioning techniques for massively distributed computation
SIGMOD '12 Proceedings of the 2012 ACM SIGMOD International Conference on Management of Data
Optimizing data shuffling in data-parallel computation by understanding user-defined functions
NSDI'12 Proceedings of the 9th USENIX conference on Networked Systems Design and Implementation
Sort-sharing-aware query processing
The VLDB Journal — The International Journal on Very Large Data Bases
Optimization of analytic window functions
Proceedings of the VLDB Endowment
SCOPE: parallel databases meet MapReduce
The VLDB Journal — The International Journal on Very Large Data Bases
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Sorting and grouping are amongst the most costly operations performed during query evaluation. System R [6] used simple inference strategies to determine orderings held of intermediate relations to avoid unnecessary sorting, and to influence join plan selection. Since then, others have proposed using integrity constraint information to infer orderings of intermediate query results. However, these proposals do not consider how to avoid grouping operations by inferring groupings, nor do they consider secondary orderings (where records in the same group satisfy some ordering). In this paper, we introduce a formalism for expressing and reasoning about order properties: ordering and grouping constraints that hold of physical representations of relations. In so doing, we can reason about how the relation is ordered or grouped, both in terms of primary and secondary orders. After formally defining order properties, we introduce a plan refinement algorithm that infers order properties for intermediate and final query results on the basis of those known to hold of query inputs, and then exploits these inferences to avoid unnecessary sorting and grouping. We then show empirical results demonstrating the benefits of plan refinement, and show that the overhead that our algorithm adds to query optimization is low.