ABSTRACT
There are time constraints expressed in terms of deadlines in real-time database systems (RTDBS) [3,7,17,19]. In firm RTDBS, transactions are required to commit before their deadlines or else the late results are useless. For example, in electronic stock trading systems, transactions that fail to meet deadlines may lead to a loss of opportunities to trade and make profit. To allow more transactions to finish before their deadlines, for scheduling purpose, a higher priority may be given to transactions with an earlier deadline. Recently, there are many research works on RTDBS. In particular, concurrency control mechanisms for maintaining database consistency in RTDBS attracted significant attention because integrating concurrency control with real-time requirements is nontrivial.
