移动数据库缓存一致性比较的矩阵校验算法研究

在移动计算系统中,移动单元通常缓存一些数据片段,但是由于移动单元的频繁断接性,缓存会与固定数据库之间发生不一致,为及时更新移动单元所缓存的数据片段,首先必须确定是否发生不一致,哪些页发生了不一致.针对该问题,在以前相关研究成果的基础上,提出一种结合了各种方法优点的新算法,通过分别在固定数据库和缓存计算数据页的校验和,并按照同样的策略将校验和排列成矩阵再进行比较,诊断出不一致的页面.有效地减少了数据传送量,提高了诊断精度,且简单易行.

A Matrix Algorithm of File Comparison to Keep Data Consistency in Mobile Database

Among the mobile computing system,mobile units usually cache some data fragment in them.,There may be some disagreements between fixed database and mobile unit cache,for they frequently connect and disconnect.In order to update the cache,we have to attain the information whether there are disagreements or not;and if disagreements do exist,which pages are not identical.On the basis of the findings of former researches,this article presents a new algorithm which combines virtues of them.This algorithm compute checksums of data pages on fixed database and mobile unit respectively,then compare the checksums after arraying them to a matrix in a same strategy,and finally diagnose the pages that are not identical.It is proved that,there are less data transfer and more diagnosis precision in our algorithm which is simple as well.