CSR: Medium: Salt: combining ACID and BASE in a distributed database

大多数大型Web应用程序都是使用分布式数据库构建的。该项目解决了一个基本问题：随着这些应用程序的增长，导致更多的查询和更新处理，我们是否可以在不需要大规模重新编程的情况下扩展应用程序性能。该项目的前提是，目前两种主要的数据库范例--ACID和BASE--严重不能令人满意。ACID实现提供了强大的属性，使得开发应用程序和推理其正确性变得容易，但随着数据库访问量的增长，它们在性能和可用性方面难以跟上；虽然基本编程范例可以满足这些需求，但代价是放弃所有ACID保证，从而极大地增加开发时间和引入错误的可能性。该项目旨在开发新的理论框架，以打破这一僵局，同时支持一致性、可用性和可伸缩性；并建立一个数据库原型，实现支持这一新框架的必要机制。该项目引入了一个新的编程框架，通过引入一个新的抽象，即基本事务，将ACID事务的易用性与基本实现的性能结合在一起。基本事务的语法和语义由两个目标驱动。首先，基本事务应该通过放松原子性和ACID范例的隔离之间过于紧密的耦合来实现高性能和可用性，同时保留其表达和执行由给定应用程序语义驱动的原子性要求的能力。其次，应该可以在不影响未经修改的ACID事务的正确性或性能的情况下，将性能关键型ACID事务转换为基本事务。为了演示这一新的编程框架，该项目将开发SALT，这是一个结合了酸和碱范例的可取特性的数据库。该项目将通过与德克萨斯州中部负责为当地医疗保健基础设施提供医疗信息技术解决方案的501(C)(3)实体的合作伙伴关系，将这项工作应用于医疗保健IT。

Most large web applications are built using distributed databases. This project tackles a fundamental question: as these applications grow, leading to more query and update processing, can we scale application performance without requiring a massive reprogramming effort. The premise of this project is that today's two leading database paradigms -- ACID and BASE -- are profoundly unsatisfying. ACID implementations provide strong properties that make it easy to develop an application and reason about its correctness, but they struggle to keep up in performance and availability as the volume of accesses to the database grows; and while the BASE programming paradigm can meet these needs, the price is to give up all ACID guarantees, drastically increasing both development time and the possibility of introducing bugs. This project aims to develop the new theoretical framework necessary to overcome this impasse and simultaneously support consistency, availability, and scalability; and to build a database prototype that implements the mechanisms necessary to support this new framework. The project introduces a new programming framework that combines the ease of ACID transactions with the performance of a BASE implementation by introducing a new abstraction, BASE transactions. The syntax and semantics of BASE transactions are driven by two goals. First, BASE transactions should achieve high performance and availability by loosening the overly-tight coupling between atomicity and isolation of the ACID paradigm, while nonetheless retaining its ability to express and enforce the atomicity requirements motivated by a given applications semantics. Second, it should be possible to surgically transform performance-critical ACID transactions into BASE transactions without affecting either the correctness or the performance of the unmodified ACID transactions. To demonstrate this new programing framework, this project will develop Salt, a database that combines the desirable qualities of both ACID and BASE paradigms. The project will apply this work to Health Care IT through a partnership with a 501(c)(3) entity in central Texas charged with providing health information technology solutions to local health care infrastructure.