Adaptive distributed query processing Grid service

Grid services provide an important abstract layer on top of heterogeneous components (hardware and software) that take part into a grid environment. We are developing a data grid service prototype that aims at providing transparent use of grid resources to data intensive scientific applications. Our prototype was designed having as target three main issues: (1) dynamic scheduling and allocation of query execution engine modules into grid nodes; (2)adaptability of query execution to variations on environment conditions and (3) support to special scientific operations. We propose a new node scheduling algorithm and show how it can be integrated into a simple distributed and parallel query optimization strategy. Our implementation demonstrates a speedup of 16.6 with 18 scheduled nodes and a steady throughput rate, obtained applying a dynamic adaptive strategy.