Research On Key Technologies Of The High Performance Publish/Subscribe Middleware HPDDSPS

With the rapid development and wide application of the Internet, the Internet has greatlychanged the size and scope of application of the distributed system.The distributed systems inthe Internet environment has characteristics of larger-scale, heterogeneous, dynamic anddecentralized control. The publish/subscribe communication paradigm can be completelydecoupled in space, time and control flow, perfectly suits the needs of today’s large-scale,distributed, highly dynamic computing environment. The existing several publish/subscribemodels offer different expressiveness, and take different performance overhead. Topic-basedpublish/subscribe is static, basic, but very effective, has a simple, intuitive user interface.Content-based publish/subscribe has higher expressiveness, but requires more complexprotocols, higher runtime overhead and more complex user interaction.For these reasons, these thesis analyses the key technologies of current publish/subscribesystem, summarizes the deficiencies, and proposes a mixing-based publish/subscribe system.It retains the topic-based interest recognition, makes the event content become visible, andprovides the support for QoS to meet users’ demand for QoS. First of all, this thesis gives thepublish/subscribe system HPDDSPS software architecture which support QoS. In order toprovide support for QoS guarantees, publishers and subscribers should be able to express QoSconstraints. This thesis uses the similar method they use to express content-based constraints.Matching algorithm should match not only event content but also QoS constraints. Based onthese analyses, we introduce the idea of multi-level index, decompose all subscriptions intomulti-level index structures, and use the covering relationship among constraints to optimizethe algorithm. In order to maintain the decoupled nature of publish/subscribe systems, thisthesis designs a new system model to integrate QoS features in publish/subscribe systems, thismodel is able to delegate the task of establishing the underlying connections on the eventbroker. Based on this model, this thesis propose a solution of multi-rendezvous, this is, foreach topic there are several rendezvous for selection. Multi-rendezvous improve the system’sperformance and scalability, and make it better fault tolerance. Based on Multi-rendezvous,this thesis design QoS-based routing algorithm, and achieve the delay and bandwidth QoSguarantees. Finally, through simulation experiments we verify the feasibility of the proposedmatching algorithm and routing algorithm, and analyze the performance of algorithm in thisthesis.