Maintaining Temporal Consistency: Issues and Algorithms

Although transaction scheduling and concurrency control issues that arise in real-time databases have been studied in detail, insufficient attention has been paid to issues that arise when real-time transactions access data with temporal validity. Such transactions must not only meet their deadlines but also read and use data that correctly reflects the environment. In this paper, we discuss the issues involved in the design of a real-time active database which maintains data temporal consistency. The concept of data-deadline is introduced and time cognizant transaction scheduling algorithms which exploit the semantics of data and transactions based on data-deadline are proposed. 1 Introduction A real-time database system is a transaction processing system designed to handle workloads where transactions have deadlines. However, many real-world applications involve not only transactions with time constraints, but also data with time constraints. Such data, typically obtained from sens..