基于遍历有向非循环图的实时事务调度算法  

Scheduling algorithms of real-time transactions based on traversing a directed acyclic graph

作　　者：向军[1] 

机构地区：[1]湖北民族学院信息工程学院,湖北恩施445000

出　　处：《计算机工程与应用》2010年第19期135-137,共3页Computer Engineering and Applications

基　　金：湖北省自然科学基金(No.2009CDB069);湖北省教育厅中青年基金(No.Q20101904);湖北民族学院博士基金(No.MY2008B039)~~

摘　　要：移动环境下实时数据库系统负载的不可预测,以及实时事务争夺有限的系统资源经常导致实时事务重启或夭折。传统的实时事务调度算法已不适应,在用有向非循环图表示数据相互间的导出关系的基础上,提出一种基于遍历这种图的实时事务调度算法。结合实时数据对象的时间域和值域有效性,系统适当地丢弃一些低价值的更新事务以减轻系统负载。仿真实验表明:算法一定程度上降低了事务错过截止期比率并提高了数据新鲜度。Real-time transactions will restart or abort possibly for competing limited system resources in low bandwidth environ-ments and the unpredictable system workloads in mobile environments.Conventional scheduling algorithms of real-time transactions cannot adapt this situation,so a novel scheduling algorithm of real-time transactions is proposed based on traversing a directed acyclic graph which describes the derived relationship of all real-time data objects.Some update transactions with low value will be discarded to reduce system workload considering the data objects validity in time domain and value domain.The deadline miss ratio of transactions can be reduced and data freshness can be improved through simulation experiments.

关 键 词：实时事务 有向非循环图 导出数据 数据新鲜度 事务错过截止期比率 反馈调度算法 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]