MULTICLASS QUERY SCHEDULING IN REAL-TIME DATABASE-SYSTEMS

In recent years, a demand for real-time systems that can manipulate la rge amounts of shared data has led to the emergence of real-time datab ase systems (RTDBS) as a research area. This paper focuses on the prob lem of scheduling queries in RTDBSs. We introduce and evaluate a new a lgorithm called Priority Adaptation Query Resource Scheduling (PAQRS) for handling both single class and multiclass query workloads, The per formance objective of the algorithm is to minimize the number of misse d deadlines, while at the same time ensuring that any deadline misses are scattered across the different classes according to an administrat ively-defined miss distribution. This objective is achieved by dynamic ally adapting the system's admission, memory allocation, and priority assignment policies according to its current resource configuration an d workload characteristics. A series of experiments confirms that PAQR S is very effective for real-time query scheduling.