D-ANTICIP: A Protocol Suitable for Distributed Real-Time Transactions

Many problems arise when we address issues on distributed real-time database systems (DRTDBMSs). A distributed database consists in general of a database located in a main site, the master, where is executed the coordinator process and of other databases located in other sites, the participant sites, where are executed cohort processes. The main problem is then to maintain the distributed database consistency while insuring that the transactions meet their deadlines. Even, in centralized RTDBMSs, this objective is difficult to reach. When the database is distributed the problem is much more difficult due to the communication delays. Hence, one of problems to solve is to manage efficiently real-time subtransactions in participant sites. A subtransaction is a part of a global transaction that executes within a participant site. In this paper, we present a protocol (D-ANTICIP) a that permits to enhance subtransactions performances, enhancing then the global transactions performances. Simulation results show that the mechanism we have used increases the number of subtransactions that meet their deadlines in comparison with the traditional protocol. because the protocol anticipates that the transactions will be aborted or committed, then it aborts useless subtransactions in descending order, beginning at the tree root (see section 4)