Asynchronous Algorithms and Concurrency Control

异步算法和并发控制

• 批准号: 8701671
• 负责人: Arthur Bernstein
• 金额: $ 15.45万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-01 至 1990-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8701671&HistoricalAwards=false
• 关键词: Asynchronous; Algorithms; Concurrency; Control

This research is concerned with improving the performance of asynchronous algorithms. These algorithms involve a number of independent activities which generally access common data. Activities must synchronize with one another to insure that data is kept consistent. Unfortunately, synchronization impairs performance. The overall goal of the research is to develop techniques for reducing synchronization requirements. Much of the research will be concerned with concurrency control in database systems and will focus on optimistic algorithms. Such algorithms are based on the assumption that synchronization is rarely needed. They allow activities to execute in an asynchronous fashion and rely on rollback if situations are detected in which activities should have synchronized. Thus, rollback is the major cost and one goal of the proposed research is to develop techniques for reducing the probability of its occurence. These include the use of semantic information about activities, the use of special techniques for handling heavily accessed regions of the data (hotspots), and the use of information that can be gathered about an activity when it is formulated as a Prolog program. The application of optimistic algorithms to replicated databases is another area of interest. Such databases have been proposed to improved the availability of data in failure situations and can also serve to enhance performance. Finally, research will be done on strategies for performing non-atomic updates on certain shared data structures. The goal is to guarantee that readers, which execute asynchronously, always function correctly.

本研究关注的是提高 异步算法 这些算法涉及许多 通常访问公共数据的独立活动。 活动 必须彼此同步，以确保数据得到保存 一致 不幸的是，同步会降低性能。 的 研究的总体目标是开发减少 同步要求。 大部分的研究将关注并发控制， 数据库系统，并将重点关注乐观算法。等 算法是基于这样的假设，即同步很少 needed. 它们允许活动以异步方式执行 并依赖回滚，如果检测到活动 应该是同步的 因此，回滚是主要的成本， 拟议研究的目标是开发减少 其发生的概率。 其中包括使用语义 关于活动的信息，使用特殊技术， 处理数据访问频繁的区域（热点），以及使用 当一项活动被执行时， 作为Prolog程序。 乐观算法在复制数据库中的应用 另一个感兴趣的领域 这些数据库已被提议用于 提高了故障情况下数据的可用性， 有助于提高性能。 最后，将研究执行非原子 更新某些共享数据结构。 我们的目标是保证 异步执行的读取器总是正确运行。