A New Approach to Real-Time Transaction Scheduling

A real-time database system differs from a conventional database system because in addition to the consistency constraints of the database, timing constraints of individual transaction need to be satisfied. Various real-time transaction scheduling algorithms have been proposed which employ either a pessimistic or an optimistic approach to concurrency control. In this paper, we present new real-time transaction scheduling algorithms which employ a hybrid approach, Le., a combination of both pessimistic and optimistic approaches. These protocols make use of a new conflict resolution scheme called dynamic adjustment of serialization order, which supports priority-driven scheduling, and avoids unnecessary aborts. Our experimental results indicate that hybrid protocols outperform other real-time concurrency control protocols in certain performance metrics.