A state transition model for distributed query processing
ACM Transactions on Database Systems (TODS)
Optimization of nested SQL queries revisited
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Query graphs, implementing trees, and freely-reorderable outerjoins
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Extensible/rule based query rewrite optimization in Starburst
SIGMOD '92 Proceedings of the 1992 ACM SIGMOD international conference on Management of data
Algebraic optimization of outerjoin queries
Algebraic optimization of outerjoin queries
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Outerjoin optimization in multidatabase systems
DPDS '90 Proceedings of the second international symposium on Databases in parallel and distributed systems
Principles of Database Systems
Principles of Database Systems
Access path selection in a relational database management system
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
Outer Joins and Filters for Instantiating Objects from Relational Databases Through Views
IEEE Transactions on Knowledge and Data Engineering
How to Extend a Conventional Optimizer to Handle One- and Two-Sided Outerjoin
Proceedings of the Eighth International Conference on Data Engineering
Supporting Flat Relations by a Nested Relational Kernel
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
SQL query optimization: reordering for a general class of queries
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Estimating alphanumeric selectivity in the presence of wildcards
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Outerjoin simplification and reordering for query optimization
ACM Transactions on Database Systems (TODS)
Data-driven understanding and refinement of schema mappings
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
Algebraic Identities and Query Optimization in a Parametric Model for Relational Temporal Databases
IEEE Transactions on Knowledge and Data Engineering
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
CASCON '95 Proceedings of the 1995 conference of the Centre for Advanced Studies on Collaborative research
No regression algorithm for the enumeration of projections in SQL queries with joins and outer joins
CASCON '95 Proceedings of the 1995 conference of the Centre for Advanced Studies on Collaborative research
Nested Queries and Quantifiers in an Ordered Context
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
Horizontal aggregations for building tabular data sets
Proceedings of the 9th ACM SIGMOD workshop on Research issues in data mining and knowledge discovery
View matching for outer-join views
VLDB '05 Proceedings of the 31st international conference on Very large data bases
Strategies for query unnesting in XML databases
ACM Transactions on Database Systems (TODS)
View matching for outer-join views
The VLDB Journal — The International Journal on Very Large Data Bases
Dynamic programming strikes back
Proceedings of the 2008 ACM SIGMOD international conference on Management of data
Semantics and complexity of SPARQL
ACM Transactions on Database Systems (TODS)
Design by example for SQL table definitions with functional dependencies
The VLDB Journal — The International Journal on Very Large Data Bases
On the correct and complete enumeration of the core search space
Proceedings of the 2013 ACM SIGMOD International Conference on Management of Data
Counter strike: generic top-down join enumeration for hypergraphs
Proceedings of the VLDB Endowment
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Complex queries containing outer joins are, for the most part, executed by commercial DBMS products in an "as written" manner. Only a very few reorderings of the operations are considered and the benefits of considering comprehensive reordering schemes are not exploited. This is largely due to the fact there are no readily usable results for reordering such operations for relations with duplicates and/or outer join predicates that are other than "simple." Most previous approaches have ignored duplicates and complex predicates; the very few that have considered these aspects have suggested approaches that lead to a possibly exponential number of, and redundant intermediate joins. Since traditional query graph models are inadequate for modeling outer join queries with complex predicates, we present the needed hypergraph abstraction and algorithms for reordering such queries with joins and outer joins. As a result, the query optimizer can explore a significantly larger space of execution plans, and choose one with a low cost. Further, these algorithms are easily incorporated into well known and widely used enumeration methods such as dynamic programming.