加速服务流程执行的组合缓存策略

发布时间：2018-04-16 02:09

本文选题：Web服务 + 服务流程　；参考：《上海交通大学》2013年硕士论文

【摘要】：将多个服务组合起来形成服务流程提供更为强大的功能已经成为一种普遍应用。在服务流程执行时，服务流程引擎解释流程逻辑并进行服务调用。为了加速服务流程的执行，可以将服务调用的数据进行缓存从而有可能直接使用缓存数据、避免服务的重复调用。本文提出了一种考虑服务在流程中关系的组合缓存机制。首先对服务流程缓存问题进行建模，提出了组合缓存的策略，定义了基于链表的组合缓存数据结构，讨论了缓存更新的策略。通过对服务调用时间的节省和存储花费分析决定缓存空间的分配。本文首先介绍了服务流程缓存的相关技术，重点介绍了科学工作流中的中间数据存储以及语义缓存技术。接着给出了基于时间代价的缓存划分算法。该算法将缓存划分为多块使用，实现了缓存组合。而后文章针对缓存块，介绍其结构并对其匹配策略、维护策略和收益花费进行了分析。最后文章使用了一个看电影的服务流程实例，通过模拟实验，测试了使用了服务流程组合缓存后，服务流程的执行时间，维护花费包括更新时间代价和存储空间，以及组合缓存的网络开销包括缓存的访问次数。实验结果表明与各个服务独立缓存相比，组合缓存更显著地加速了流程执行，同时，其使用的总体资源较少，，服务失效时的缓存更新时间也更少。
[Abstract]:Combining multiple services into a service process to provide a more powerful function has become a universal application.When the service process executes, the service process engine interprets the process logic and makes the service call.In order to speed up the execution of the service process, the data of the service call can be cached so that it is possible to use the cached data directly and avoid the repeated invocation of the service.This paper proposes a composition caching mechanism considering the relationship between services in the process.Firstly, the service flow caching problem is modeled, and the policy of composite cache is proposed, the data structure of composite cache based on linked list is defined, and the strategy of cache updating is discussed.The allocation of cache space is determined by analyzing the saving of service call time and the cost of storage.This paper first introduces the related technologies of service flow caching, focusing on the intermediate data storage and semantic caching technology in scientific workflow.Then a cache partition algorithm based on time cost is presented.The algorithm divides the cache into multiple blocks and implements the cache combination.Then, the structure of cache block is introduced and its matching strategy, maintenance strategy and revenue cost are analyzed.Finally, the paper uses a movie service flow example, through the simulation experiment, tests the service process execution time after using the service process composition cache, the maintenance cost includes the update time cost and the storage space.The network overhead of the combined cache includes the number of times the cache is accessed.The experimental results show that the composite cache speeds up the process execution more significantly than the individual service cache. At the same time the total resources are less and the cache update time is less when the service fails.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP393.09;TP333

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