空间数据库系统中树的并发控制设计与实现

Design and Implementation of Concurrency Control of R-tree in Spatial Database System

R树是实现快速空间数据处理的重要索引结构之一,但由于其并发控制的复杂性,虽研究已久但仍然很少真正地集成到商用数据库中。树是为了实现并发控制而提出的一种树结构的变形,但它仍然存在幻像等问题。文章分析了树中存在的这一问题并通过设R-linkRR-link计一个基于内存的操作控制列表来预先避免可能造成幻像的并发操作,从而实现完全的并发控制。实验证明所(Operation Control List, OCList)提方案是正确的、低开支的,而且有利于提高系统性能。

R-tree is an important index structure for fast spatial data processing. Despite extensive research on R-trees, most of proposed schemes have not been integrated into commercial DBMS due to the complexity of concurrency control. R-link tree is a variation of R-tree used to deal with this issue, but problems such as phantom still exist. This paper analyses these problems and proposes an in-memory operation control list (OCList) to prevent conflicting operations and thus realize the complete concurrency control. The experiment results show that this scheme is correct, low overhead and can gain better system performance. ;;;;