Dynamic real-time optimistic concurrency control
Jayant R. Haritsa,Michael J. Carey,Miron Livny +2 more
- pp 94-103
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TLDR
A new real-time optimistic concurrency control algorithm, WAIT-50, is presented that monitors transaction conflict states and gives precedence to urgent transactions in a controlled manner and is shown to provide significant performance gains over OPT-BC under a variety of operating conditions and workloads.Abstract:
The authors (1990) have shown that in real-time database systems that discard late transactions, optimistic concurrency control outperforms locking. Although the optimistic algorithm used in that study, OPT-BC, did not factor in transaction deadlines in making data conflict resolution decisions, it still outperformed a deadline-cognizant locking algorithm. A discussion is presented of why adding deadline information to optimistic algorithms is a nontrivial problem, and some alternative methods of doing so are described. A new real-time optimistic concurrency control algorithm, WAIT-50, is presented that monitors transaction conflict states and gives precedence to urgent transactions in a controlled manner. WAIT-50 is shown to provide significant performance gains over OPT-BC under a variety of operating conditions and workloads. >read more
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References
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Proceedings Article
Scheduling Real-time Transactions: a Performance Evaluation
TL;DR: In this paper, the authors developed a new family of algorithms for scheduling real-time transactions with deadlines, which have four components: a policy to manage overloads, a policy for scheduling the CPU, access to data, concurrency control and scheduling I/O requests on a disk device.
Journal ArticleDOI
Scheduling real-time transactions: a performance evaluation
TL;DR: This thesis develops a new family of algorithms for scheduling real-time transactions and proposes new techniques for handling requests without deadlines and requests with deadlines simultaneously, finding that real- time disk scheduling algorithms can perform better than conventional algorithms.