Current applications, such as Web-based services, electronic commerce, mobile telecommunication systems, etc. are distributed in nature and manipulate time-critical databases. In order to enhance the performance and the availability of such applications, the major issue is to develop efficient protocols that cooperate with the scheduler to manage the overload of the distributed system. In order to help real-time database management systems (RTDBS) to maintain data logical consistency while attempting to enhance concurrency execution of transactions, we introduce a transactional multimode model to let the application transactions adapt their behavior to the overload consequences. In this paper, we propose for each transaction several execution modes and we derive an overload controller suitable for the proposed multimode model.