Abstract
Inthis paper, we study the performance of using optimistic approachto concurrency control in distributed real-time database systems(RTDBS). The traditional optimistic approach suffers from theproblem of unnecessary restarts. Transaction restarts can significantlyincrease the system workload and intensify resource and datacontention. In distributed environments, the complexity of thesystem and the high communication overhead exacerbate the problem.Therefore, the number of unnecessary restarts is the determinantfactor that affects the performance of optimistic approach indistributed RTDBS. When optimistic approach is extended to distributedenvironments, a number of issues resulting from the increasedcomplexity and communication overhead have to be resolved. Inthis paper, a new real-time distributed optimistic concurrencycontrol (DOCC) protocol with dynamic adjustment of serializationorder (DASO), called DOCC-DA is proposed. This protocol can avoidunnecessary transaction restarts by dynamically adjusting theserialization order of the conflicting transactions. Therefore,resources can be saved and more transactions can meet their deadlines.In the DOCC-DA protocol, a new distributed circular validationscheme is included to facilitate transaction validation in distributedenvironments. The performance of the DOCC-DA protocol has beenexamined in detail by simulation. The results showed that theperformance of the DOCC-DA protocol is consistently better thanthat of other protocols.
Similar content being viewed by others
References
Abbott, R., and Garcia-Molina, H. 1988. Scheduling real-time transactions: A performance evaluation. Proceedings of the 14th VLDB Conference. Los Angeles, pp. 1–12.
Abbott, R., and Garcia-Molina, H. 1992. Scheduling real-time transactions: A performance evaluation. ACM Transactions on Database Systems 17(3): 513–560.
Bernstein, P. A., Hadzilacos, V., and Goodman, N. 1987. Concurrency Control and Recovery in Database Systems. Mass: Addison-Wesley.
Datta, A., Viguier, I. R., Son, S. H., and Kumar, V. 1997. A study of priority cognizance in conflict resolution for firm real time database systems. Real-Time Database and Information Systems, Research Advances. Boston. Kluwer Academic Publishers.
Haerder, T. 1984. Observations on optimistic concurrency control schemes. Information Systems 9(2).
Haritsa, J. R., Carey, M. J., and Livny, M. 1990a. Dynamic real-time optimistic concurrency control. Proceedings of 11th Real-time Systems Symposium. Florida, pp. 94–103.
Haritsa, J. R., Carey, M. J., and Livny, M. 1990b. On being optimistic about real-time constraints. Proc. of the ACM SIGACT-SIGART-SIGMOD Symp. on Principles of Database Systems.
Haritsa, J. R., Carey, M. J., and Livny, M. 1992. Data access scheduling in firm real-time database systems. Real-time Systems4(3): 203–242.
Huang, J., Stankovic, J. A., Towsley, D., and Ramamritham, K. 1991. Experimental evaluation of real-time optimistic concurrency control schemes. Proc. of the 17th VLDB Conf. Spain, pp. 35–46.
Huang, J., Stankovic, J. A., Ramamritham, K., Towsley, D., and Purimetla, B. 1992. On using priority inheritance in real-time databases. Real-time Systems 4(3): 243–268.
Konana, P., Lee, J., and Ram, S. 1997. Updating timestamp interval for dynamic adjustment of serialization order in optimistic concurrency control-time interval (OCC-TI) protocol. Information Processing Letters 63(4): 189–193.
Kung, H. T., and Robinson, J. T. 1981. On optimistic methods for concurrency control. ACM Transactions on Database Systems 6(2): 213–226.
Lam, K. Y. 1994. Concurrency control in distributed real-time database systems. Department of Computer Science, City University of Hong Kong, Ph.D. Thesis.
Lam, K. Y., Hung, S. L., and Son, S. H. 1997. On using real-time static locking protocols for distributed real-time databases. Real-Time Systems 13: 141–166.
Lam, K. W., Lam, K. Y., and Hung, S. L. 1995. Real-time optimistic concurrency control protocol with dynamic adjustment of serialization order. Proceedings of IEEE Symposium on Real-time Technology and Applications. pp. 174–181.
Lee, J., and Son, S. H. 1993a. An optimistic concurrency control protocol for real-time database systems. Proc. of the 3rd Int. Symp. on Database Systems for Advanced Applications. Korea.
Lee, J., and Son, S. H. 1993b. Using dynamic adjustment of serialization order for real-time database systems. Proceedings of 14th IEEE Real-time Systems Symposium. North Carolina, pp. 66–75.
Lee, J., and Son, S. H. 1996. Concurrency control algorithms for real-time database systems. Performance of Concurrency Control Mechanisms in Centralized Database Systems. V. Kumar, ed., Prentice Hall.
Ramamritham, K. 1993. Real-time databases. International Journal of Distributed and Parallel Databases 1: 199–226.
Sha, L., Rajkumar, R., and Lehoczky, J. 1988. Concurrency control for distributed real-time databases. ACM SIGMOD Record. pp. 82–98.
Sha, L, Rajkumar, R., and Lehoczky, J. P. 1990. Priority inheritance protocols: An approach to real-time synchronization. IEEE Transactions on Computers 39(9): 1175–1185.
Son, S. H., and Chang, C. 1990. Performance evaluation of real-time locking protocols using a distributed software prototyping environment. Proceedings of the 10th International Conference on Distributed Computing Systems. Paris, pp. 124–131.
Son. S. H., and Koloumbis, S. 1993. A token-based synchronization scheme for distributed real-time databases. Information Systems18(6): 375–389.
Ulusoy, O., and Belford, G. G. 1992. A simulation model for distributed real-time database systems. Proceedings of 25th Annual Simulation Symposium. pp. 232–240.
Ulusoy, O. 1994. Processing real-time transactions in a replicated database system. Technical Report BU-CEIS-94-13, Bilkent University.
Yu, P. S., Wu, K. L., Lin, K. J., and Son, S. H. 1994. On real-time databases: Concurrency control and scheduling. Proceedings of the IEEE 82(1): 140–157.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lam, Kw., Lee, V.C.S. & Hung, Sl. Transaction Scheduling in Distributed Real-Time Systems. Real-Time Systems 19, 169–193 (2000). https://doi.org/10.1023/A:1008145516902
Issue Date:
DOI: https://doi.org/10.1023/A:1008145516902