Abort-oriented concurrency control for real-time databases

There has been growing interest in the performance of transaction systems t hat have significant response time requirements. These requirements are usu ally specified as hard or soft deadlines on individual transactions and a c oncurrency control algorithm must attempt to meet the deadlines as well as preserve data consistency. This paper proposes a class of simple and effici ent abort-oriented concurrency control algorithms in which the schedulabili ty of a transaction system is improved by aborting transactions that introd uce excessive blockings. We consider different levels of the aborting relat ionship among transactions and evaluate the impacts of the aborting relatio nship when the relationship is built in an online or offline fashion. We me asure aborting overheads on a system running the LynxOS real time operating system. The strengths of the work are demonstrated by improving the worst- case schedulability of an avionics example [20]; a satellite control system [7], and randomly generated transaction sets.