移动复制数据库系统冲突检测及消解策略  

Conflict Detection and Resolution Strategy in Replicated Mobile Database Systems

作　　者：丁治明[1] 王珊[1] 孟小峰[2] 

机构地区：[1]中国科学院计算技术研究所,北京100080 [2]中国人民大学数据与知识工程研究所,北京100872

出　　处：《计算机学报》2002年第3期297-305,共9页Chinese Journal of Computers

基　　金：国家"八六三"高技术研究发展计划(863 -3 0 6-ZD12 -12 -1);国家自然科学基金(60 0 73 0 14 )资助

摘　　要：复制技术是提高移动数据库系统性能的一项关键技术 .该文提出了一种新的移动复制数据库系统模型——事务级结果集传递 (TL RSP)移动复制模型 ,重点分析了该模型中的冲突检测及消解策略 ,并给出了具体的实现算法 ;TL RSP移动复制模型允许移动用户在系统断连时存取数据库的本地副本并提交事务 ,重新连接时进行冲突的检测及消解 ,同时进行事务结果集的合并 ,最后通过增量刷新的方式进行同步处理 ,使得系统最终收敛于一致性的状态 .此外 ,通过引入简化的事务日志、数据版本号以及权限控制等概念 ,TL RSP模型有效地降低了移动数据库系统的资源消耗 ,保证了数据库的一致性 。A new mobile database replication scheme, Transaction-Level Result-Set Propagation (TLRSP) model, is put forward. The conflict detection and resolution strategy of TLRSP model is discussed in detail, and the implementation algorithm is proposed. In TLRSP model, mobile users are allowed to access local replicas of the database and locally commit mobile transactions when the system is disconnected. The locally committed transactions are sent to the fixed database server for conflict reconciliation and result-set incorporation when the system is reconnected. In order to ensure database consistency, transactions locally committed at mobile hosts need to be validated at the database server before they can be globally committed. Therefore, mobile transactions that have executed conflicting operations will be aborted, and only those mobile transactions that do not violate the consistency of the database system can be globally committed. TLRSP model uses an incremental refresh method, and only recently updated data need to be transmitted during the synchronization process. Besides, by utilizing a simplified log structure and by introducing version number and access control into the system, TLRSP model reduces the resource consumption and communication costs. To sum up, through an efficient conflict reconciliation and result-set propagation strategy, TLRSP model provides a flexible and effective solution to the replication problem of mobile database systems.

关 键 词：事务处理 数据库系统 移动复制技术 冲突检测 消解策略 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]