A monitoring service for large-scale dynamic query optimisation in a grid environment
International Journal of Web and Grid Services
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
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Execution plans generated by traditional optimizers for large scale distributed queries can be sub-optimal because: the estimations are inaccurate, the data are unavailable and the execution environment is unstable. To deal with the sub-optimality, we propose to execute each relational operator of an execution plan by a mobile agent. A mobile agent can change its execution site in order to correct the sub-optimality. In this paper, we address the problem of choosing an execution site for a mobile agent among execution sites of the considered system. For this, we propose to integrate a cost model into the mobile agents. We define also the various interactions that might occur between a mobile agent and its execution site. The performance evaluation shows that the cost model embedded in the agent allows to choose the most appropnhte execution site.