Research issues for a real-time nested transaction model

Real-time database systems have been studied to meet stringent timing and reliability constraints that were observed in many application areas. In some applications, many transactions must be not only executed correctly but also completed within their deadlines, and soma data may become invalid after a certain duration of time. For some of these advanced applications, transactions are long and complicated. A transaction model beyond the conventional single-level transaction models is needed to manage the complexity. In order to extend current real-time transactions to a nested transaction model several issues need to be explored or re-examined. We discuss two important issues: how to propagate deadlines from a transaction to its subtransactions and how to control concurrent execution of nested transactions