ASGT:基于预测和自适应性的移动事务并发控制方法  

ASGT:An Approach to Concurrency Control in Mobile Transaction Management Based on Prediction and Adaptation

作　　者：李晓荣[1] 施伯乐[2] 

机构地区：[1]上海交通大学安泰管理学院,上海200052 [2]复旦大学计算机与信息技术系,上海200433

出　　处：《计算机研究与发展》2006年第2期295-300,共6页Journal of Computer Research and Development

基　　金：国家自然科学基金重点项目(69933010);国家自然科学基金项目(70172011)~~

摘　　要：在高质量的无线通信网络中,带宽不稳定和用户移动性成为影响移动事务处理的主要因素,导致事务冲突率上升、吞吐量下降和峰值情况复杂等结果·一种新的并发控制方法ASGT能够:①具有比2PL更小的阻塞面和更高的并发度;②预先发现非串行化调度,有效降低阻塞率,缩短阻塞时间·ASGT结合MWDL方法能够提高系统性能,降低调度代价·理论分析和模拟实验证明了ASGT方法的性能·Mobile transaction management is one of the most important fields in the research of mobile database. Though disconnection will never be a main problem in the high quality of wireless network nowadays, the high instability of bandwidth still produces a larger fluctuation of transaction executing time which leads to a higher blocking rate. Furthermore, due to high density of MUs, the database server will work under a high workload circumstance and meet the thrashing in a larger probability. A new scheme, called ASGT （active serialization graph technique）, is developed to overcome these problems. In the ASGT, reading never blocks writing, thus it can substantially reduce the blocking rate. The ASGT can detect and break some non-serializable scheduling in advance, which can greatly shorten the suspending time of transactions involved. Due to an explicit serializable sequence maintained in running time, the scheduler, integrating an aborting method called MWDL, can improve the throughput and reduce the scheduling cost. The theoretical analysis and execution of a simulation based on C ＋＋ SIM show that the performance of the ASGT overmatches an improved 2PL in most conditions of a mobile environment.

关 键 词：移动事务 ASGT 2PL 自适应 性能 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]