Rethinking Transaction Recovery for High Availability and Performance

多核体系结构和非易失性内存（NVM）的出现促使人们重新考虑已建立的事务恢复技术。这导致了针对现代硬件平台的大量设计。这种设计通常与传统的基于磁盘的设计不兼容，而且比传统的基于磁盘的设计更复杂。例如，最近以nvm为中心的方法通常不支持介质恢复，而介质恢复对于可靠的数据服务至关重要。其他方法依赖于专门的硬件，例如定制的I/O控制器或特殊的CPU指令。在这个项目中，我们的目标是重新审视事务恢复的经典原则，并通过仔细改变基本假设，设计出在传统和现代架构上都能工作的简单算法。这样的新算法能够利用现代计算机体系结构的性能优势，而不会牺牲媒体恢复等关键特性或需要专门的硬件。我们的方法基于两类算法：即时恢复和REDO-only恢复。前者是惠普实验室发起的一个项目，目前正在与我们的研究小组合作开发。即时恢复旨在通过支持在事务运行时按需增量恢复数据页，从而大幅减少修复数据库系统的平均时间。在这个项目提案中，我们的目标是通过实现即时恢复来继续这项工作，它将即时恢复的想法应用于媒体故障。后一组算法已经被我们的研究小组概念化了，我们的目标是在这个项目的背景下实现和评估它们。目标是为提交处理和传播控制设计新的策略，从而产生“仅限redo”的恢复算法，这种算法可以很容易地应用于分布式日志和非易失性存储器，从而充分利用现代硬件架构的潜力。我们的最终目标是将这两种算法组合到一个系统设计中，以实现高效、健壮、高可用性和硬件透明的事务处理。

The emergence of many-core architectures and non-volatile memory (NVM) motivates a reconsideration of established techniques for transaction recovery. This recently led to a multitude of designs tailored to modern hardware platforms. Such designs are often incompatible with and more complex than traditional disk-based designs. For instance, recent NVM-centric approaches usually do not support media recovery, which is essential for reliable data services. Other approaches rely on specialized hardware, such as tailor-made I/O controllers or special CPU instructions.In this project, we aim to revisit classical principles of transaction recovery and, by carefully changing fundamental assumptions, devise simple algorithms that work on both traditional and modern architectures.Such new algorithms are able to exploit the performance benefits of modern computer architectures without sacrificing crucial features such as media recovery or requiring specialized hardware.Our approach is based on two families of algorithms: Instant Recovery and REDO-only Recovery. The former is a project initiated at HP Labs and currently being developed in a collaboration with our research group.Instant Recovery aims to drastically reduce the mean time to repair of database systems by supporting incremental, on-demand recovery of data pages while transactions are running.In this project proposal, we aim to continue this work by implementing Instant Restore, which applies Instant Recovery ideas to media failures.The latter family of algorithms has been conceptualized by our research group and we aim to implement and evaluate them in the context of this project. The goal is to devise new strategies for commit processing and propagation control, leading to "REDO-only" recovery algorithms which can be easily applied to distributed logging and non-volatile memories, thus exploiting the full potential of modern hardware architectures.Our final goal is to combine these two families of algorithms into a system design for efficient, robust, highly available, and hardware-transparent transaction processing.