Predictive speculative concurrency control for real-time database systems

Real-Time Database Systems (RTDBSs) are designed to manage the majority of current applications which manipulate a large volume of data and have a great need of real-time computation. One of the main issues in the DBMSs is to control the access to the same data items by the transactions in incompatible mode. In RTDBSs, this problem becomes more complicated since the transaction manager must not only avoid data access conflicts, but it has also to provide mechanisms that help transactions to meet their deadlines, to maximize the transactions success ratio. In this paper, we describe The SCC protocol (Speculative Concurrency Control) which is one of the first concurrency control protocol RTDBS. It is based on the transactions duplicating transactions. However, the SCC raises some problems; we propose a new extension of this protocol to solve these problems and to increase the number of transactions meeting their deadline.