International Journal of Applied Information Systems |
Foundation of Computer Science (FCS), NY, USA |
Volume 4 - Number 1 |
Year of Publication: 2012 |
Authors: Mohammad Hussein |
10.5120/ijais12-450656 |
Mohammad Hussein . Mobile Join Algorithms based on Mobiles Agents for Large Scale Distributed Query Optimization. International Journal of Applied Information Systems. 4, 1 ( September 2012), 54-68. DOI=10.5120/ijais12-450656
In the large scale distributed environment, the query optimization presents new problems because of the data unavailability, the estimations inaccuracies and environment instability. In this paper, we address the sub-optimality of executions plans caused by these problems. We propose to extend the join algorithms based on mobile agents in order to correct the sub-optimality. This extension allows the join to change their execution site. Indeed, the mobile agent executing a join adapts to changes in characteristics of the execution environment (e. g. network bandwidth, available memory) and responds to the estimations inaccuracies (e. g. size of intermediate relations). The performance evaluation shows that the proposed algorithms improve the response time whatever the variation of estimations errors.