On the optimal nesting order for computing N-relational joins
ACM Transactions on Database Systems (TODS)
Translating SQL Into Relational Algebra: Optimization, Semantics, and Equivalence of SQL Queries
IEEE Transactions on Software Engineering
Magic sets and other strange ways to implement logic programs (extended abstract)
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
The Alexander method-a technique for the processing of recursive axioms in deductive databases
New Generation Computing
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Journal of Logic Programming
Is there anything better than magic
Proceedings of the 1990 North American conference on Logic programming
Query optimization for parallel execution
SIGMOD '92 Proceedings of the 1992 ACM SIGMOD international conference on Management of data
Fundamentals of database systems (2nd ed.)
Fundamentals of database systems (2nd ed.)
Efficient sampling strategies for relational database operations
ICDT Selected papers of the 4th international conference on Database theory
Compiling query constraints (extended abstract)
PODS '94 Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Implementation of magic-sets in a relational database system
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Optimization and execution techniques for queries with expensive methods
Optimization and execution techniques for queries with expensive methods
Query processing in a system for distributed databases (SDD-1)
ACM Transactions on Database Systems (TODS)
Equivalence of Relational Algebra and Relational Calculus Query Languages Having Aggregate Functions
Journal of the ACM (JACM)
Approximating block accesses in database organizations
Communications of the ACM
Space/time trade-offs in hash coding with allowable errors
Communications of the ACM
Access path selection in a relational database management system
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
An extended relational algebra with control over duplicate elimination
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
The VLDB Journal — The International Journal on Very Large Data Bases - Prototypes of deductive database systems
Starburst Mid-Flight: As the Dust Clears
IEEE Transactions on Knowledge and Data Engineering
An Optimization Strategy for Recursive Queries in Logic Databases
Proceedings of the Fourth International Conference on Data Engineering
Optimization of Nonrecursive Queries
VLDB '86 Proceedings of the 12th International Conference on Very Large Data Bases
VLDB '92 Proceedings of the 18th International Conference on Very Large Data Bases
The Volcano Optimizer Generator: Extensibility and Efficient Search
Proceedings of the Ninth International Conference on Data Engineering
Query execution techniques for caching expensive methods
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
SIGMOD '97 Proceedings of the 1997 ACM SIGMOD international conference on Management of data
An overview of query optimization in relational systems
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Changing the rules: transformations for rule-based optimizers
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
Optimization techniques for queries with expensive methods
ACM Transactions on Database Systems (TODS)
Query optimization in the presence of limited access patterns
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
Context interchange: new features and formalisms for the intelligent integration of information
ACM Transactions on Information Systems (TOIS)
Logical Approach to Capability-Based Rewriting in a Mediator for WebSources
Journal of Intelligent Information Systems
Filtering with Approximate Predicates
VLDB '98 Proceedings of the 24rd International Conference on Very Large Data Bases
Implementation of Two Semantic Query Optimization Techniques in DB2 Universal Database
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Online Dynamic Reordering for Interactive Data Processing
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
EROC: A Toolkit for Building NEATO Query Optimizers
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
The Complexity of Transformation-Based Join Enumeration
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
Optimization of Nested SQL Queries by Tableau Equivalence
DBPL '99 Revised Papers from the 7th International Workshop on Database Programming Languages: Research Issues in Structured and Semistructured Database Programming
The VLDB Journal — The International Journal on Very Large Data Bases
A nested relational approach to processing SQL subqueries
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Implementing sorting in database systems
ACM Computing Surveys (CSUR)
Cost-based query transformation in Oracle
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Strategies for query unnesting in XML databases
ACM Transactions on Database Systems (TODS)
Magic Sets and their application to data integration
Journal of Computer and System Sciences
The use of Hints in SQL-Nested query optimization
Information Sciences: an International Journal
SQL query optimization through nested relational algebra
ACM Transactions on Database Systems (TODS)
Foundations and Trends in Databases
Adding magic to an optimising datalog compiler
Proceedings of the 2008 ACM SIGMOD international conference on Management of data
Optimization of multi-domain queries on the web
Proceedings of the VLDB Endowment
Scalable join processing on very large RDF graphs
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
QueryPIE: backward reasoning for OWL horst over very large knowledge bases
ISWC'11 Proceedings of the 10th international conference on The semantic web - Volume Part I
Magic sets and their application to data integration
ICDT'05 Proceedings of the 10th international conference on Database Theory
Chapter 10: join methods and query optimization
Search Computing
Magic Sets for disjunctive Datalog programs
Artificial Intelligence
Finitely recursive programs: Decidability and bottom-up computation
AI Communications
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Magic sets rewriting is a well-known optimization heuristic for complex decision-support queries. There can be many variants of this rewriting even for a single query, which differ greatly in execution performance. We propose cost-based techniques for selecting an efficient variant from the many choices.Our first contribution is a practical scheme that models magic sets rewriting as a special join method that can be added to any cost-based query optimizer. We derive cost formulas that allow an optimizer to choose the best variant of the rewriting and to decide whether it is beneficial. The order of complexity of the optimization process is preserved by limiting the search space in a reasonable manner. We have implemented this technique in IBM's DB2 C/S V2 database system. Our performance measurements demonstrate that the cost-based magic optimization technique performs well, and that without it, several poor decisions could be made.Our second contribution is a formal algebraic model of magic sets rewriting, based on an extension of the multiset relational algebra, which cleanly defines the search space and can be used in a rule-based optimizer. We introduce the multiset θ-semijoin operator, and derive equivalence rules involving this operator. We demonstrate that magic sets rewriting for non-recursive SQL queries can be modeled as a sequential composition of these equivalence rules.