Theory and design of adaptive filters
Theory and design of adaptive filters
Federated database systems for managing distributed, heterogeneous, and autonomous databases
ACM Computing Surveys (CSUR) - Special issue on heterogeneous databases
Interoperability of multiple autonomous databases
ACM Computing Surveys (CSUR) - Special issue on heterogeneous databases
The CORDS multidatabase project
IBM Systems Journal
Reducing multidatabase query response time by tree balancing
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
Query caching and optimization in distributed mediator systems
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Cost-based query scrambling for initial delays
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
Solving Local Cost Estimation Problem for Global Query Optimization in Multidatabase Systems
Distributed and Parallel Databases
A fuzzy query optimization approach for multidatabase systems
International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems
Building regression cost models for multidatabase systems
DIS '96 Proceedings of the fourth international conference on on Parallel and distributed information systems
Query Optimization in Multidatabase Systems Considering Schema Conflicts
IEEE Transactions on Knowledge and Data Engineering
A Query Sampling Method of Estimating Local Cost Parameters in a Multidatabase System
Proceedings of the Tenth International Conference on Data Engineering
Cost Models DO Matter: Providing Cost Information for Diverse Data Sources in a Federated System
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Query Optimization in a Heterogeneous DBMS
VLDB '92 Proceedings of the 18th International Conference on Very Large Data Bases
Calibrating the Query Optimizer Cost Model of IRO-DB, an Object-Oriented Federated Database System
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
DEXA '00 Proceedings of the 11th International Conference on Database and Expert Systems Applications
Leveraging Mediator Cost Models with Heterogeneous Data Sources
ICDE '98 Proceedings of the Fourteenth International Conference on Data Engineering
Developing Cost Models with Qualitative Variables for Dynamic Multidatabase Environments
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
Evolutionary techniques for updating query cost models in a dynamic multidatabase environment
The VLDB Journal — The International Journal on Very Large Data Bases
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Deriving local cost models for query optimization in a multidatabase system (MDBS) is a challenging issue due to local autonomy. It becomes even more difficult when dynamic environmental factors are taken into consideration. In this paper, we study how to evolve a cost model to capture a slowly-changing dynamic MDBS environment so that the cost model is kept up-to-date all the time. We propose a novel evolutionary technique, called the shifting method, to tackle this issue. The key idea is to adjust a cost model by adding the up-to-date performance information of a new sample query into and, in the meantime, removing the out-of-date information of the oldest sample query from consideration at each step. It is shown that this method is more efficient than the direct re-building approach. The relevant issues including derivation of recurrence update formulas, development of efficient algorithm, analysis of complexities as well as some aspects of implementation are studied. Our theoretical and experimental results demonstrate that the proposed shifting method is quite promising in deriving accurate evolutionary cost models for a slowly-changing dynamic MDBS environment.