排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
Leslie Lamport 《Distributed Computing》1992,6(1):65-71
The photograph and autobiography of Dr. Leslie Lamport were published in Volume 4, Issue No. 2, 1990 on page 59 相似文献
2.
数据库的共享性是建立在多个共享事务的并发执行基础之上的。为了保证多个事务的并发执行,并发控制器对各事务动作的调度应当是可串行化的。然而,在实际调度过程中,并非所有的调度都是可串行化的。为了确保事务之间的可串行性关系,可使用两阶段封锁将非可串行化调度强制实现为可串行化调度。 相似文献
3.
网格技术的本质就是提高资源的共享能力和实现计算资源的协同处理能力.网格数据库就是使传统数据库能够充分利用网格平台的这种优势,实现传统数据库的存储、管理、处理、分析等能力的共享和协同.网格数据库中的事务也存在全局事务和局部事务之分,对全局事务要保证得到正确的执行结果,其串行化是关键.给出了网格数据库全局事务的形式化定义,以及全局事务实现串行化的条件,并进行了相关证明. 相似文献
4.
5.
6.
The usual criterion of serializability considered in data base systems in order to control the accesses to shared informations by concurrent transactions is generalized in two directions: the transactions can be arbitrarily often iterated, as processes in an operating system, and the notion of serialization is extended in order to control behaviours of concurrent transactions with respect to several independent criteria of serializability. For transaction systems controlled under multiple criteria of serializability, a characterization of deadlock freedom is given. This characterization is shown to be applicable to any mutual exclusion problem. 相似文献
7.
John T. Robinson 《Software》1984,14(9):827-844
The designer of a concurrency control is currently faced with a confusing situation: there has been a proliferation of proposed methods (in fact, it will be shown here that even in the ‘simple’ centralized case there are infinitely many methods), and although there has been some analysis of a few alternative methods using simulation and analytic models, it is usually impossible to accurately predict some of the parameters required by these models prior to the development of a system. Furthermore, over the lifetime of a system some parameters will change, possibly radically, due to changes in system usage, the replacement or addition of processors, memories, and I/O devices, the development of new applications, etc. Here, a practical approach to this problem is presented: separating policy from correctness in the design of the concurrency control. This technique was successfully used in the development of a transaction processing system for the Cm* multi-microprocessor. As an illustration of this approach, the design of the concurrency control of this system is described in detail. This design should apply directly to any centralized single-level (non-hierarchical) concurrency control. 相似文献
8.
《国际计算机数学杂志》2012,89(10):1203-1211
The model of concurrent uninterpreted transactions [Papadimitriou, C. H. (1979). The serializability of concurrent database updates. J. ACM, 26, 631–653.] is extended to histories with infinitely many occurrences of the transactions. Such histories are viewed as models of linear temporal logic formulae with propositions representing read and write steps of transactions. A necessary and sufficient condition for histories to be serializable is encoded into temporal logic by the use of propositional quantification. The encoding differs from work on commutativity-based serializability and partial-order temporal logics in using linear temporal logic and defining serializability in terms of uninterpreted histories without reference to the state of variables. An application is the specification of a weaker form of serializability where commutativity of steps is not determined by past history. 相似文献
9.
描述了一种可以为分布式工作流提供事务支持的模型设计、并提出了一种柔性事务模型。给出了柔性事务的定义,然后描述了保证柔性事务被正确调度的可串行化正确性准则。该模型具有在多层工作流管理系统中处理分布式业务流程的能力。 相似文献
10.
研究了实时广播中的数据一致性问题。传统冲突可串行化并发控制协议对非对称通信的广播环境来说过于严格且不必要。为此,提出使用Q可串行化:形式化定义了Q可串行化,证明了它虽比传统冲突可串行化宽松但能始终保证数据一致性,基于可动态调整串行化顺序的时标段排序方法给出了相应的并发控制协议。实验结果表明:新协议可显著降低平均响应时间,使更多移动实时事务满足截止期要求。 相似文献