Abstract
Concurrency control algorithms for real-time database systems satisfy not only consistency requirements but also meet transaction-timing constraints. Two Phase Locking (2PL) is used often in traditional database systems. However, it has some inherent problems such as the possibility of deadlocks as well as long and unpredictable blocking times. Optimistic concurrency control protocols are non-blocking and deadlock free, but they have the problems of late conflict detection and transaction restarts. Other Concurrency Control techniques, such as Dynamic Adjustment of Serialization Order (DASO) have been found to be better at reducing number of transaction restarts. In this paper, we propose a new optimistic concurrency control algorithm based on DASO using firm deadline in order to effectively reduce number of unnecessary restarts. Since firm real time transaction imparts no value to the system once its deadline expires, therefore in our algorithm, we adjust the timestamp intervals of all conflicting active transactions only after the validating transaction is guaranteed to meet its deadline during the validation phase. A simulator is designed to verify the effectiveness of the proposed method. The simulation results show that the proposed method can significantly reduce the number of unnecessary restarts and thereby improve the miss ratio, commit ratio.
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References
Kao, B., Garcia-Molina, H.: An overview of real-time database systems. In: Son, S.H. (ed.) Advances in Real-Time Systems, pp. 463–486. Prentice Hall, Englewood Cliffs (1995)
Ramamritham, K.: Real-Time Databases. Distributed and Parallel Databases 1 (1993)
Lindstrom, J.: Optimistic Concurrency control Methods in Real Time Database Systems. Lincentiate Thesis, Series of publications C, Report C-2001-9, Helsinki (Febuary 2001)
Lee, J.: Concurrency Control Algorithms for Real Time Database Systems. PhD thesis, faculty of the school of Engineering and Applied Science, University of Virginia (January 1994)
Lindstrom, J., Raatikainen, K.: Dynamic adjustment of serialization order using timestamp intervals in real-time databases. In: Proceedings of the 6th International Conference of Real-Time Computing Systems and Applications, pp. 13–20. IEEE Computer Society Press, Hong Kong (1998)
Lindstrom, J., Raatikainen, K.: Using importance of transactions and optimistic concurrency control in firm real-time database. In: Proceedings of the 7th International Conference of Real-Time Computing Systems and Applications, pp. 463–467. IEEE Computer Society Press, Cheju Island (2000)
Datta, A., Son, S.H.: A study of concurrency control in real-time active database systems. Tech. Report, department of MIS, university of Arizona, Tucson (1996)
Datta, A., Viguier, I.R., Son, S.H., Kumar, V.: Is a bird in the hand worth more than two in the bush? Limitations of priority cognizance in conflict resolution for firm real-time database systems. IEEE Transactions on Computers 49(5), 482–502 (2000)
Yu, P.S., Wu, K.L., Lin, K.J., Son, S.H.: On Real-time Databases: ConcurrencControl and Scheduling. Proc. of the IEEE 82(1), 140–157 (1994)
Bestavros, A., Braoudakis, S.: A family of speculative concurrency control algorithms: Technical Report TR-92-017, Computer Science Department, Boston University, Boston, MA (July 1992)
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© 2005 Springer-Verlag Berlin Heidelberg
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Jalal, A.S., Tanwani, S., Ramani, A.K. (2005). Optimistic Concurrency Control in Firm Real-Time Databases. In: Pal, A., Kshemkalyani, A.D., Kumar, R., Gupta, A. (eds) Distributed Computing – IWDC 2005. IWDC 2005. Lecture Notes in Computer Science, vol 3741. Springer, Berlin, Heidelberg. https://doi.org/10.1007/11603771_53
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DOI: https://doi.org/10.1007/11603771_53
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-30959-8
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