一种基于关键属性的优化数据一致性维护方法  

An Optimistic Data Consistency Maintenance Method Based on Key-Attributes

作　　者：周婧[1] 王意洁[1] 李思昆[1] 

机构地区：[1]国防科学技术大学计算机学院并行与分布处理国家重点实验室,湖南长沙410073

出　　处：《软件学报》2008年第8期2114-2126,共13页Journal of Software

基　　金：国家自然科学基金Nos.60503042;69903011;国家自然科学基金创新研究群体科学基金No.60621003;国家重点基础研究发展计划(973)No.2002CB312105;高等学校全国优秀博士学位论文作者专项资金项目No.200141~~

摘　　要：针对关键属性更新的易描述、更新项较小和弱相关性三个特点。提出一种基于关键属性的优化数据一致性维护方法.在该方法中,首先分离出用户提交的更新请求中关于关键属性的更新;然后采用基于延迟.覆盖的更新传播模型进行更新传播,即基于副本间的网络延迟选择具有最大和最小网络延迟的结点转发更新,并在传播过程中记录和综合考虑更新的确定传播和不确定传播两条路径;在对关键更新冲突分类的基础上,采用更新缓冲区和更新日志两层更新协商机制并结合最新写胜出和分而治之规则,优化关键更新冲突的发现和解决:更新日志信息是方法中各种策略开展的基础,讨论了更新日志中信息管理方法以及结点失效和网络划分发生时信息的维护方法.关键属性更新的优化处理使得不会产生因为关键属性更新的延迟而降低系统基于关键属性的资源定位效率,满足面向Internet的P2P系统的要求.模拟测试结果表明,该方法在一致性维护开销、资源定位开销与资源访问开销以及鲁棒性方面均具有较好的性能.The features of simple description, small updates item and weak dependence are the main characteristics of updates of key-attributes in P2P systems. Accordingly, an optimistic data consistency maintenance method based on key-attributes is proposed. In the method, the update of key-attributes is separated from user update requests. Key-Updates are propagated by latency-overlay update propagation model, that is, updates are always propagated to the nodes having maximum or minimum latency, and assured and uncertain propagation paths of updates are all taken into account. Based on classifying key-update conflicts, a double-level reconciling mechanism including buffer preprocessing and update-log processing is applied to detect and reconcile conflicts, and then conflicts are solved by policies as last-writer-win and divide-and-rule. Lastly, update-log management method and maintenance method brought by node failure and network partitioning are discussed for the above is deployed based on the information storied in update-log. Delaying key-attributes updates cannot occur by the optimistic disposal method, and then it cannot depress efficiency of resource location based on key-attributes, which adapts well to P2P systems for Internet. The simulation results show that it is an effective optimistic data consistency maintenance method, achieving good consistency overhead, resource location and resource access overhead, and having strong robustness.

关 键 词：P2P分布存储系统 数据复制 数据一致性 资源定位 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]