A Concurrency Control Strategy Of Embedded Mobile Real-time Transactions

With the increasing request of the efficiency in real-time application and the fast development of mobile communication technology, Embedded Mobile Real-time Database System which integrate the mobile computation, real-time application and traditional database technology become a focus in the research of database. The transaction processing in this system should consider about the limitation of resource, time and efficiency, so that the transactions could fit the demand of their real-time and mobile characteristic.Besides maintaining the characteristics of traditional transactions, the embedded mobile real-time transactions should focus on how to resolve the problem of priority reversing, fruitless restarting, consistency of global data and high performance of the mixed transactions system. Optimistic Concurrency Control with Absolute Serialize Time Order and Selected Restart (OCC-ASTOSR) is an available and effectual strategy of the control of embedded mobile real-time transactions.OCC-ASTOSR uses an absolute timestamp to adjust the serialize order of transactions in mobile client and central server, checks over the confliction of data access, and take the Selected Restart method to resolve the confliction. Transactions update their read set and write set when access the data and every data maintains some relational time information, they exchange message via wireless network and complete two phase validation in the control of the whole system.Proved by the theory of the serialization of transactions, the transactions schedule which produced by OCC-ASTOSR strategy is serialized. Simulated experiment shows that OCC-ASTOSR is better than some other strategies on miss rate, count of restarting and system throughput.