Object-Based Semantic Real-Time Concurrency Control

This paper presents a technique that is capable of supporting two major requirements for concurrency control in real-time databases: data temporal consistency, and data logical consistency, as well as tradeo s between these requirements. Our technique is based upon a real-time object-oriented database model in which each object has its own unique compatibility function that expresses the conditional compatibility of any two potential concurrent operations on the object. The conditions use the semantics of the object, such as allowable imprecision, along with current system state, such as time and the active operations on the object. Our concurrency control technique enforces the allowable concurrency expressed by the compatibility function by using semantic locking controlled by each individual object. The real-time object-oriented database model and process of evaluating the compatibility function to grant semantic locks are described.