摘要
本文指出对普通的B^+树作了一定的限制后,当选择B^+树适当的阶数m时,对B^+树索引文件的时间和空间利用率有一个最优的设计过程。分别给出了应用在两种数据库系统模型中的B^+树索引文件结构:(1)具有有限内存的数据库系统(DatabaseSystems with Limited Amount of Main Memory,简称为DBSLAM),在DBSLAM模型中,我们只是缓存B^+树中的部分结点;(2)具有极大内存的数据库系统(Database Systems with Very Large Amount of Main Memory,简称为DBSVLAM),在DBSVLAM模型中,我们将缓存B^+树中所有的结点。基于以上两种模型,我们分别建立了两个不同的时空开销模型,并以此进行了优化设计。
Optimization is proposed of a designing procession for using the conventional B+- tree while it is limited and a suitable order m is chosen. Here we will discuss the optimization under two different models of database systems: Database Systems with Limited Amount of Main Memory (DBSLAM) and Database Systems with Very Large Amount of Main Memory( DBSVLAM). In the model of DBSLAM, we store only a part of nodes of B+- tree and build a model of using time - space. In the model of DBSVLAM, we store all of the nodes of B+- tree and build a model of using time - space.Basing on the two models,the mathematical methods for optimization are also presented.
出处
《计算机应用与软件》
CSCD
北大核心
2002年第7期57-61,共5页
Computer Applications and Software
