CSR: Small: Scalable Transactional Replication: Theory, Protocols, and Middleware Systems

CSR：小型：可扩展事务复制：理论、协议和中间件系统

• 批准号: 1523558
• 负责人: Binoy Ravindran
• 金额: $ 45万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2019-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1523558&HistoricalAwards=false
• 关键词: CSR; Small; Scalable; Transactional; Replication

With the exponentially increasing popularity of web-based networked applications, their back-end IT systems must process an ever growing volume of data and service requests. Obtaining high scalability is challenging when application workloads generate concurrent accesses on shared data that is replicated to ensure data survival and service availability in the presence of failures. The classical transactional technology for solving this problem -- State Machine Replication -- does not scale: regulating the commits of distributed transactions requires solving consensus, whose leader is a significant scalability bottleneck. Leaderless consensus protocols unfruitfully pay the cost of large quorums for providing fast decisions only whenever possible. To overcome these limitations, the project is developing two complimentary techniques for building scalable consensus protocols for transactional systems. In the first technique, called the Caesar approach, consensus decisions are always made in two communication delays, i.e., fast decisions, using a scheme based on proposed positions: a transaction activated on a node, i.e., the transaction's coordinator, is executed on all nodes at a position proposed by the transaction's coordinator, and after the execution of any other conflicting transaction that was chosen at a lesser position. To achieve that, the transaction's coordinator only needs to know that the proposed position is not rejected by a fast quorum of nodes. However, by exploiting network delays and clock drift estimates, the positions are adjusted in a way such that they are never rejected. Thus, the cost of using fast quorums larger than the ones necessary to solve consensus in order to exploit a fast decision is amortized by the ability of always deciding in that way. In the second technique, called the M^2Paxos approach, the order of transactions is generally decided in only two communication delays by relying on the classical quorum size that is strictly necessary to solve consensus, i.e., a majority of nodes. This is achieved by exploiting application's data access locality. In particular, in case of low contention, M^2Paxos inspects the data to be accessed by a submitted transaction and determines the node responsible for ordering the transaction. This allows all transactions accessing the same data to be implicitly ordered by the same node.The project is transitioning Caesar and M^2Paxos into the experimental, open-source HyFlow transactional middleware system, which enables adoption of the techniques by the research community at large. Additionally, the project is transitioning the techniques into Red Hat/JBoss's production transactional middleware, Infinispan, which enables adoption of the techniques by J2EE developers at large.

随着基于Web的网络应用程序的指数增长，其后端IT系统必须处理越来越多的数据和服务请求。当应用程序工作负载生成共享数据的并发访问时，获得高可伸缩性是具有挑战性的，该数据被复制以确保在存在故障的情况下数据存活和服务可用性。解决此问题的经典交易技术 - 状态机器的复制 - 没有扩展：调节分布式交易的提交需要解决共识，其领导者的领导者是显着的可扩展性瓶颈。无领导者共识协议无权支付大型法定人数的费用，以便尽可能提供快速的决策。为了克服这些局限性，该项目正在开发两种免费的技术，用于构建交易系统的可扩展共识协议。在第一种技术（称为凯撒方法）中，总是在两个沟通延迟中做出共识的决定，即快速决策，使用基于提议的职位的方案：在节点上激活的交易，即交易协调员，是由交易协调员的所有节点上的所有节点上执行的。为了实现这一目标，交易的协调员只需要知道所提出的位置不会被快速的节点Quorum拒绝。但是，通过利用网络延迟和时钟漂移估计，以从不拒绝的方式调整了这些位置。因此，使用快速法定人数大于解决共识以利用快速决策所需的快速方案的成本，这是通过以这种方式决定的能力来摊销的。在第二种技术（称为M^2paxos方法）中，交易顺序通常仅在两个通信延迟中决定，而依赖于解决共识（即大多数节点）的经典群体大小。这是通过利用应用程序的数据访问区域来实现的。特别是，如果有较低的争议，m^2paxos检查了由提交的交易访问要访问的数据，并确定负责订购交易的节点。这允许所有访问相同数据的交易被同一节点隐式排序。该项目正在将凯撒和M^2paxos转换为实验性开源的Hyflow交易中间件系统，从而使研究社区总体上采用了技术。此外，该项目正在将技术转变为Red Hat/Jboss的生产交易中间件Infinispan，该工艺中的中间件使J2EE开发人员在整个开发人员中采用了这些技术。