Locking Protocols for Concurrency Control in Real-Time Database Systems

Concurrency Control in real-time database systems is complicated by the requirement to maintain database consistency at the same time to minimize the number of transactions missing their deadlines. The scheduling of data in Basic Two Phase Locking 1992 completely ignores the urgency of a transaction and thus the effectiveness of the adopted real-time resource scheduling protocol is greatly reduced. In Restart based locking protocols (R2PL), same priorities are used for both data and resources scheduling and should have fewer transactions missing their deadlines. However, Restart based protocols sufferred the intrinsic weakness of high restart overhead owing to ensure atomicity of transactions. In this paper, based on their weaknesses, a hybrid concurrency control protocol (H2PL) is proposed. Through performance study, results indicate that it can perform well under different degree of deadline constraint and workload as compared with other real-time locking protocols. © 1992, ACM. All rights reserved.