On new scheduling policy for the improvement of firm RTDBSs performances

Earliest deadline first (EDF) is one of the main scheduling policies used in real-time database systems (RTDBSs) for transactions processing. With EDF, prioritized transactions are not necessarily the most important in the system. Moreover, it is well-known that EDF is not efficient in overload conditions. In this paper, we introduce the notion of transaction importance and present a new priority assignment technique based on both transactions importance and deadlines. This assignment policy leads to a new scheduling policy, called generalized earliest deadline first (GEDF). In order to show the benefits of using GEDF for managing real-time transactions, we have designed an RTDBS simulator and carried out Monte Carlo simulations.