Precise serialization for optimistic concurrency control

摘要

Despite the fact that transaction implementation in most commercial database management systems uses locking for concurrency control, optimistic concurrency control has recently gained attention for its efficiency in new types of data-intensive applications such as computer-aided design, computer-aided software engineering, and computer integrated manufacturing applications. This paper describes and analyzes a new concurrency control algorithm referred to as precise serialization, a variation of an optimistic concurrency control algorithm using forward validation that is known to outperform other optimistic algorithms proposed so far. We show that the forward validation-based algorithm incurs transaction restarts which are not absolutely necessary to ensure data consistency, and that the precise serialization algorithm solves this problem with a reasonably limited amount of effort by dynamically adjusting transaction execution history. We illustrate, through simulation, that by removing such unnecessary restarts, the precise serialization algorithm improves the performance of the forward validation-based algorithm under certain conditions.