READS: A prototyping environment for real-time active applications

In this paper, we present our REal-time Active Database System, READS, which is a prototyping environment for real-time active database applications on a conventional Unix environment, e.g., Solaris 2.4. In READS, transactions are associated with deadlines and priorities. Priority scheduling is supported by the real-time extensions provided in the underlying operating system. READS can be served as a testbed for evaluating different issues in the design of real-time active database systems (RTADBS). Different approaches for assigning deadlines and priorities to triggered transactions have been suggested and discussed. An application, the programmed trading database system, is implemented with READS and experiments have been performed to study the impact of the deadline constraints on the performance of the deferred and immediate coupling modes for triggering.