A Performance Model for Computer Data-Base Reorganization Performed Concurrently with Usage

Characteristics of data bases, reorganization, concurrent reorganization, and data-storage devices are described briefly. We present a two-priority queuing model for concurrent reorganization and usage and derive and solve equations for steady-state expectations of user response time and the time required to perform reorganization. Numerical results are obtained, and performance characteristics of such a system are predicted quantitatively. We discuss the effect of parameter values on performance and predict that for typical values of the model's parameters, system performance will be at an acceptable level.