Improving the SCC protocol for real-time transaction concurrency control

For real-time DBMSs (RTDBMSs), both the integrity constraints of the database and the temporal constraints of the transactions must be respected. In this paper, we focus on the SCC real-time concurrency control protocol proposed by Bestavros et al. (1992, 1995, 1993). It is based on the duplication of the transactions and the use of the transaction timestamps to resolve the transaction conflicts. Despite its great performances in real-time distributed DBMSs (Bestavros A et al., 1993), we propose an extension of the protocol to improve this performances in two ways: (1) the write-write conflicts are resolved with a particular method that is, to our mind, not applicable in real-time context and (2) for other conflicts, we propose an extended deadline-driven method combined with the transaction duplication. In this way, more transactions respect their deadlines.