Equi-depth multidimensional histograms
SIGMOD '88 Proceedings of the 1988 ACM SIGMOD international conference on Management of data
SIGMOD '88 Proceedings of the 1988 ACM SIGMOD international conference on Management of data
Practical selectivity estimation through adaptive sampling
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
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
Error-constrained COUNT query evaluation in relational databases
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
On global multidatabase query optimization
ACM SIGMOD Record
A fuzzy query optimization approach for multidatabase systems
International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems
Query Optimization in Database Systems
ACM Computing Surveys (CSUR)
Access path selection in a relational database management system
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
Accurate estimation of the number of tuples satisfying a condition
SIGMOD '84 Proceedings of the 1984 ACM SIGMOD international conference on Management of data
A Query Sampling Method of Estimating Local Cost Parameters in a Multidatabase System
Proceedings of the Tenth International Conference on Data Engineering
Simple Random Sampling from Relational Databases
VLDB '86 Proceedings of the 12th 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
Query optimization in multidatabase systems
CASCON '92 Proceedings of the 1992 conference of the Centre for Advanced Studies on Collaborative research - Volume 2
An integrated method for estimating selectivities in a multidatabase system
CASCON '93 Proceedings of the 1993 conference of the Centre for Advanced Studies on Collaborative research: distributed computing - Volume 2
Query processing with quality control in the World Wide Web
World Wide Web
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
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
DEXA '00 Proceedings of the 11th International Conference on Database and Expert Systems Applications
Knowledge and Information Systems
Evolutionary techniques for updating query cost models in a dynamic multidatabase environment
The VLDB Journal — The International Journal on Very Large Data Bases
Query cost estimation through remote system contention states analysis over the Internet
Web Intelligence and Agent Systems
Selectivity estimation of range queries based on data density approximation via cosine series
Data & Knowledge Engineering
Distributed and Parallel Databases
A monitoring service for large-scale dynamic query optimisation in a grid environment
International Journal of Web and Grid Services
Cluster-and-conquer: hierarchical multi-metric query processing in large-scale database federations
Proceedings of the Fourteenth International Database Engineering & Applications Symposium
Progressive query optimization for federated queries
EDBT'06 Proceedings of the 10th international conference on Advances in Database Technology
Fuzzy reward modeling for run-time peer selection in peer-to-peer networks
FSKD'05 Proceedings of the Second international conference on Fuzzy Systems and Knowledge Discovery - Volume Part I
Fuzzy cost modeling for peer-to-peer systems
AP2PC'03 Proceedings of the Second international conference on Agents and Peer-to-Peer Computing
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To meet users‘ growing needs for accessing pre-existing heterogeneousdatabases, a multidatabase system (MDBS) integrating multiple databases has attracted many researchers recently. A key feature of an MDBS is local autonomy. For a query retrieving data from multiple databases, global query optimization should be performed to achieve good system performance. There are a number of new challenges for global query optimization in an MDBS. Among them, a major one is that some local optimization information, such as local cost parameters, may not be available at the global level because of local autonomy. It creates difficulties for finding a good decomposition of a global query during query optimization. To tackle this challenge, a new query sampling method is proposed in this paper. The idea is to group component queries into homogeneous classes, draw a sample of queries from each class, and use observed costs of sample queries to derive a cost formula for each class by multiple regression. The derived formulas can be used to estimate the cost of a query during query optimization. The relevant issues, such as query classification rules, sampling procedures, and cost model development and validation, are explored in this paper. To verify the feasibility of the method, experiments were conducted on three commercial database managementsystems supported in an MDBS. Experimental results demonstrate that the proposed method is quite promising in estimating local cost parameters in an MDBS.