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
On global multidatabase query optimization
ACM SIGMOD Record
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
Multidatabase Query Optimization
Distributed and Parallel Databases
Solving Local Cost Estimation Problem for Global Query Optimization in Multidatabase Systems
Distributed and Parallel Databases
Stochastic processes
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
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
Developing Evolutionary Cost Models for Query Optimization in a Dynamic Multidatabase Environment
On the Move to Meaningful Internet Systems, 2002 - DOA/CoopIS/ODBASE 2002 Confederated International Conferences DOA, CoopIS and ODBASE 2002
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Research on query cost estimation for local database systems in a multidatabase system (MDBS) has attracted many researchers in the datebase area recently. Obtaining good query cost estimates is crucial for performing effective global query optimization in an MDBS. However, performing suggested so far, including database calibrating and query sampling, consider only a static multidatabase environment. Recently, we proposed a qualitative approach to developing cost models for a dynamic multidatabase environment. It has been shown that this approach is promising in estimating the cost of a query run in any given contention state for a dynamic environment. However, a large (cost) query in pratice may experience multiple contention states during its execution, which cannot be directly handled by the qualitative approach. In this paper, we propose two new techniques, i.e., fractional analysis and probabilistic approach, to solve the problem. The fractional analysis technique, which is suitable for a system environment that changes contention states gradually and smoothly, estimates a query cost by analyzing its fractions. The probabilistic approach, which is suitable for a system environment that changes contention states rapidly and randomly, estimates a query cost based on the theory of Markov chains. Cost estimation formulas for both techniques are deriver, and their properties are studied. Our experimental results demonstrate that the suggested techniques are quite promising in estimating costs for large queries in a dynamic multidatabase environment.