Fundamentals of database systems (2nd ed.)
Fundamentals of database systems (2nd ed.)
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Optimizing queries using materialized views: a practical, scalable solution
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
Exploiting statistics on query expressions for optimization
Proceedings of the 2002 ACM SIGMOD international conference on Management of data
Database System Concepts
The Complexity of Transformation-Based Join Enumeration
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
The Volcano Optimizer Generator: Extensibility and Efficient Search
Proceedings of the Ninth International Conference on Data Engineering
Conditional selectivity for statistics on query expressions
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
Consistently estimating the selectivity of conjuncts of predicates
VLDB '05 Proceedings of the 31st international conference on Very large data bases
Fast approximate computation of statistics on views
Proceedings of the 2006 ACM SIGMOD international conference on Management of data
Consistent selectivity estimation via maximum entropy
The VLDB Journal — The International Journal on Very Large Data Bases
Cardinality estimation using sample views with quality assurance
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
Self-tuning database systems: a decade of progress
VLDB '07 Proceedings of the 33rd international conference on Very large data bases
A pay-as-you-go framework for query execution feedback
Proceedings of the VLDB Endowment
Relational support for flexible schema scenarios
Proceedings of the VLDB Endowment
Parallelizing extensible query optimizers
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
Query optimizers: time to rethink the contract?
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
StatAdvisor: recommending statistical views
Proceedings of the VLDB Endowment
Re-optimizing data-parallel computing
NSDI'12 Proceedings of the 9th USENIX conference on Networked Systems Design and Implementation
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The quality of execution plans generated by a query optimizer is tied to the accuracy of its cardinality estimation. Errors in estimation lead to poor performance, erratic behavior, and user frustration. Traditionally, the optimizer is restricted to use only statistics on base table columns and derive estimates bottom-up. This approach has shortcomings with dealing with complex queries, and with rich languages such as SQL: Errors grow as estimation is done on top of estimation, and some constructs are simply not handled. In this paper we describe the creation and utilization of statistics on views in SQL Server, which provides the optimizer with statistical information on the result of scalar or relational expressions. It opens a new dimension on the data available for cardinality estimation and enables arbitrary correction. We describe the implementation of this feature in the optimizer architecture, and show its impact on the quality of plans generated through a number of examples.