Tradeoffs in processing complex join queries via hashing in multiprocessor database machines
Proceedings of the sixteenth international conference on Very large databases
On the propagation of errors in the size of join results
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Answering queries using templates with binding patterns (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
An overview of query optimization in relational systems
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Efficient mid-query re-optimization of sub-optimal query execution plans
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
An adaptive query execution system for data integration
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
Eddies: continuously adaptive query processing
SIGMOD '00 Proceedings of the 2000 ACM SIGMOD international conference on Management of data
WSQ/DSQ: a practical approach for combined querying of databases and the Web
SIGMOD '00 Proceedings of the 2000 ACM SIGMOD international conference on Management of data
A probe-based technique to optimize join queries in distributed Internet databases
Knowledge and Information Systems
Processing Distributed Mobile Queries with Interleaved Remote Mobile Joins
IEEE Transactions on Computers
Mobile Agents for World Wide Web Distributed Database Access
IEEE Transactions on Knowledge and Data Engineering
Multi-Join Optimization for Symmetric Multiprocessors
VLDB '93 Proceedings of the 19th International Conference on Very Large Data Bases
Efficient Querying of Distributed Resources in Mediator Systems
On the Move to Meaningful Internet Systems, 2002 - DOA/CoopIS/ODBASE 2002 Confederated International Conferences DOA, CoopIS and ODBASE 2002
Exploiting the Features of Asymmetry for Query Processing in a Mobile Computing Environment
CooplS '02 Proceedings of the 7th International Conference on Cooperative Information Systems
Query containment for data integration systems
Journal of Computer and System Sciences - Special issue on PODS 2000
Query planning and optimization in information integration
Query planning and optimization in information integration
Mobile Agent Cooperation Methods for Large Scale Distributed Dynamic Query Optimization
DEXA '03 Proceedings of the 14th International Workshop on Database and Expert Systems Applications
Computing complete answers to queries in the presence of limited access patterns
The VLDB Journal — The International Journal on Very Large Data Bases
Optimizing Recursive Information Gathering Plans in EMERAC
Journal of Intelligent Information Systems
Query Processing and Optimization on the Web
Distributed and Parallel Databases
Adapting to source properties in processing data integration queries
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
The use of Hints in SQL-Nested query optimization
Information Sciences: an International Journal
Evolution of Query Optimization Methods: From Centralized Database Systems to Data Grid Systems
DEXA '09 Proceedings of the 20th International Conference on Database and Expert Systems Applications
Dynamic query optimisation: towards decentralised methods
International Journal of Intelligent Information and Database Systems
Mobile Information Systems
Impact of Applying Aggregate Query Processing in Mobile Commerce
International Journal of Business Data Communications and Networking
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We consider the problem of query execution when there is limited access to the relations, i.e. when binding patterns require values to be specified in order to get data from the relation. This problem is common in virtual data integration systems where there are heterogeneous sources with various restricted access patterns and query capabilities. Another problem is the lack of the statistical information about the sources and occurrence of unpredictable events. We introduce two mobile join operators, MDJoin and SMDJoin which are designed for restricted sources and implemented using 'mobile agents' in order to benefit from their autonomous and reactive characteristics. Mobile operators of restricted sources are capable to deal with restricted sources and react to the variations between the compile-time estimations and run-time computations of data during query execution. The difference between the two new query operators lies in their level of adaptation ability to the execution environment. Performance results show that mobile agent-based approach at operator level can lead to a significant reduction in response time with restricted sources.