Efficient Resource Utilization in Shared-Everything Environments

E cient resource usage is a key to achieve better performance in parallel database systems. Up to now, most research has focussed on balancing the load on several resources of the same type, i.e. balancing either CPU load or I/O load. In this paper, we present oating probe, a strategy for parallel evaluation of pipelining segments in a shared-everything environment that provides dynamic load balancing between CPUand I/O-resources. The key idea of oating probe is to overlap|as much as possible with respect to data dependencies|I/O-bound build phase and CPU-bound probe phase of pipelining segments to improve resource utilization. Simulation results show, that oating probe achieves shorter execution times while consuming less memory than conventional pipelining strategies. 1991 Computing Reviews Classi cation System: [H.2.4] Parallel Database Systems, Query Processing