SITE AND QUERY SCHEDULING POLICIES IN MULTICOMPUTER DATABASE-SYSTEMS

We study run-time issues. such as site allocation and query scheduling policies, in executing read-only queries in a hierarchical, distribut ed memory, multicomputer system. The particular architecture considere d here is based on the hypercube interconnection. The data are stored in a base cube, which is controlled by a control cube and host node hi erarchy. Input query trees are transformed into operation sequence tre es, and the operation sequences become the units of scheduling. These sequences are scheduled dynamically at run-time. Algorithms for dynami c site allocation are provided. Several query scheduling policies that support interquery concurrency are also studied. Average query comple tion times and initiation delays are obtained for the various policies using simulations.