消息联盟系统中保持消息因果序协议的研究

由多个代理服务器组成的消息中间件联盟系统提供了更好的扩展性，但没有保证消息之间的因果序关系。该文提出并设计了一个新的保证消息因果序的通信协议MOMCO，该协议基于向量时钟，不但保证在消息联盟系统中消息的因果序，而且携带的排序控制信息量小，避免了采用二维矩阵时钟导致的较高代价，适用于大规模应用的场合。

Preserving Causality in Federated Message-oriented Middleware

To enhance scalability of message-oriented middleware (MOM), a popular pattern is the use of multiple nodes as a federation of message routers that pass messages from node to node until messages reach their destination. But the federated system introduces message-ordering problem. The paper presents a novel protocol to guarantee causal order through vector clocks in federated MOM. The protocol keeps the cost of extra order information attached to messages to be linear and applies to large-scale application. The algorithm is implemented and is very efficient, low-cost and easy to understand.