Fault-Tolerant Algorithms for Distributed Databases

分布式数据库中数据的可用性可以通过复制来提高，其中数据对象可以具有驻留在不同站点上的多个副本。如果复制了数据，则它可能在故障后仍可用。然而，这种数据可用性的增加可能会导致操作执行成本的增加。本文提出的研究旨在开发以低成本提高数据可用性的方法。此外，我们探索的机制允许数据在站点或通信故障的情况下保持可访问，即使此类故障导致网络分区。我们建议为容错并发控制协议开发一种新的范例。这一范式加深了我们对这类协议的理解，并为我们开发新的协议提供了新的见解。我们特别提出了开发协议，允许执行只读事务，并在具有定义良好的信息流模式的数据库中高效执行事务。最后，我们建议研究提高抽象数据对象的可用性的方法，其中关于数据库中的数据对象的语义信息是可用的。

The availability of data in a distributed database can be increased by replication, where a data object may have several copies residing on different sites. If data is replicated, it may still be available after failures. However, this increase in data availability may result in an increase in the cost of opertion execution. The research proposed herein seeks to develop methods that increase data availability at low costs. Futhermore, the mechanisms we explore allow the data to remain accessible in spite of site or communication failures, even when such failures lead to network partitioning. We propose to develop a new paradigm for fault tolerant concurrency control protocols. This paradigm furthers our understanding of such protocols, and provides us with new insights for the development of new protocols. We specifically proposed development protocols that allow the execution of read-only transactions and the efficient execution of transactions in databases with well defined information flow patterns. Finally, we propose to investigate methods for increasing the availability of abstract data objects where semantic information is available about the data objects in the databaase.