PATCOM:基于分割树的无结构P2P系统一致性维护方法

无结构P2P技术逐渐被应用在新型的协同计算系统中.这些新型业务支持数据的动态更新,不仅要求副本数据的强一致性,而且要求更新数据的快速传播.高效的一致性维护方法是保证新业务顺利开展的基础.在比较分析现有的P2P系统一致性维护方法的基础上,针对无结构P2P系统,提出了一种基于分割树的一致性维护方法--PATCOM.PATCOM使用Chord协议作为组管理协议,通过不断分割由副本节点组成的Chord环,动态地建立更新消息传播树(Update Message Propagation Tree,UMPT).论文进一步从理论上分析了UMPT的平均高度、PATCOM的性能、容错能力以及算法开销,并和基于Gossip的一致性维护方法进行了比较.理论分析和仿真实验结果表明:PATCOM不仅能够快速地维护P2P系统的强一致性,而且产生的冗余更新消息少.

PATCOM: Partition Tree-Based Consistency Maintenance for Unstructured P2P Systems

Unstructured P2P technique is gradually applied in newly-developed cooperative computing systems. These applications support the dynamical updates of data, and require not only strong consistency but also fast propagation of update messages. An efficient consistency maintenance method is the basis for the developing of newly-developed applications. Based on intensive analysis and comparisons for existing methods, the authors propose a partition tree-based consistency maintenance scheme for unstructured P2P systems, PATCOM. PATCOM uses Chord as the group management protocol and propagates update messages along with the Update Message Propagation Tree (UMPT), which is built dynamically on top of the Chord ring composed of replica nodes. The authors theoretically analyze the average height of UMPT, the performance of PATCOM, the failure tolerance and the overhead of the proposed scheme. Then, the authors compare PATCOM with the Gossip-based consistency maintenance method. Finally, they verify the theoretical results and the performance of PATCOM by simulation experiments. The performance analysis and simulation results show that PATCOM not only maintains a strict consistence, but also brings fewer redundant update messages.