On Being Optimistic about Real-Time Constraints

- Performancestudiesof concurrencycontrol algorithms for conventional database systems have shown that, under most operating circumstances, locking protocols outperform optimistic techniques. Real-timedatabase systems have special characteristics - timing constraints are associated with transactions, performance criteria are based on satisfaction of these timing constraints, and scheduling algorithms are priority driven. In light of these special characteristics, results regarding the performance of concurrency control algorithms need to be re-evaluated. Weshow in this paper that the following parameters of the real-time database system - its policy for dealing with transactions whose constraints are not met, its lolowledge of transaction resource requirements, and the availability of resources have a significant impact on the relative performance of the concurrency control algorithms. In particular, we demonstrate that under a policy that discards transactions whose constraints are no...

• Type: Conference
• Year: 1990
• Where: PODS
• Authors: Jayant R. Haritsa, Michael J. Carey, Miron Livny
• Keywords: Concurrency Control Algorithms, Database, Database Systems, PODS 1990, Timing Constraints