Dynamic adjustment of serialization order using time-stamp intervals in real-time databases

Although an optimistic approach has been shown to be better than locking protocols for real-time database systems (RTDBS), it has the problems of unnecessary restarts and heavy restart overhead. In this paper we propose a new optimistic concurrency control protocol called OCC-DATI. In OCC-DATI the number of transaction restarts is minimized by dynamic adjustment of the serialization order of the conflicting transactions. The need for dynamic adjustment of the serialization order is checked and the serialization order is updated in the validation phase. This provides more freedom to adjust the serialization order of conflicting transactions. OCC-DATI has several advantages over other optimistic concurrency control protocols. The protocol maintains all the nice properties with forward validation, a high degree of concurrency freedom front deadlock, and early detection and resolution of conflicts, resulting in both fewer wasted resources and a smaller number of restarts. All of these are important to the performance of RTDBSs and contribute to greater chances of meeting transaction deadlines. Performance studies of our protocol have been carried out in RTDBS and the results confirm that the performance of the OCC-DATI is better than other well-known OCC protocols.