Optimistic Concurrency Control Algorithm with Dynamic Serialization Adjustment for Firm Deadline Real-Time Database Systems
A new optimistic concurrency control algorithm for firm deadline real-time database systems is presented. The algorithm dynamically adjusts a serialization order among conflicting transactions and, thus, tries to reduce the number of unnecessary restarts of transactions. Instead of aborting a lower priority transaction being in conflict with already committed higher priority transaction the algorithm is looking for a new serialization order, i.e. it tries to serialize the transaction before the conflicting one. Through simulation experiments, we evaluate the performance of the algorithm, and compare the algorithm with two well-known optimistic concurrency control algorithms: OCC and OPT-BC. Experimental results have shown that the performance of the algorithm depends on a system workload. The probability of successful reordering of conflicting transactions decreases with the increasing number of conflicts between the transactions.
KeywordsGuaran Tocol Mellon Cuted
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- R. Abbott, and H. Garcia-Molina. Scheduling Real-Time Transactions: a Performance Evaluation. In Proceedings of the 14th VLDB Conference, Los Angeles, California, 1988.Google Scholar
- R. Abbott, H. Garcia-Molina. Scheduling Real-time Transactions with Disk Resident Data. In Proceedings of the 15th VLDB Conference, pages 385–395, Amsterdam, 1989.Google Scholar
- A. P. Buchmann, D. R. McCarthy, M. Hsu, and U. Dayal. Time-Critical Database Scheduling: A Framework For Integrating Real-Time Scheduling and Concurrency Control. In Proc. of Data Engineering Conference, February 1989.Google Scholar
- J. R. Haritsa, M.J. Carey, and M. Livny. On Being Optimistic about Real-Time Constraints. In Proceedings of the 9th SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, April 1990.Google Scholar
- J. Huang, J. A. Stankovic, K. Ramamritham, and D. Towsley. Experimental Evaluation of Real-Time Optimistic Concurrency Control Schemes. In Proceedings of the 17th VLDB Conference, pages 35–46, September 1991.Google Scholar
- W. Kim, J. Srivastava. Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling. In Proc of 12th IEEE Real-Time Systems Symposium, 1991.Google Scholar
- H. Kung, and J. Robinson. On Optimistic Methods for Concurrency Control. ACM Transactions on Database Systems, 6(2), June 1981.Google Scholar
- D. Menasce, T. Nakanishi, Optimistic Versus Pessimistic Concurrency Control Mechanisms in Database Management Systems. Information Systems, 7(1), 1982.Google Scholar
- U. Praedel, G. Schlageter, and R. Unland. Redesign of Optimistic Methods: Improving Performance and Applicability. In Proceedings of International Conference on Data Engineering, Los Angeles, 1986.Google Scholar
- J. Robinson. Design of Concurrency Controls for Transaction Processing Systems, Ph.D. Thesis, Computer Science Department, Carnegie Mellon University, 1982.Google Scholar