【摘要】 在实时数据库中,事务对时态数据对象的访问在很多领域的应用日益广泛。目前实时数据库中的事务调度算法大多仅考虑数据的逻辑一致性,而忽略了满足时态的一致性。论文提出了新的实时数据库中具有时态限制的事务调度算法PSBA(PredictionandSimilarity-BasedAlgorithm)。首先提出了临时数据截止期的概念,以定理的形式证明了低成本地预测算法的可行性,尽可能早地终止或推迟无法满足时态一致性要求的事务的执行,节省了计算资源以供其它事务执行。继而通过挖掘数据语义,利用数据相似性,结合预测算法,进一步提高了调度性能。与目前所知的有效算法比较,该算法在性能指标上(事务失败率、浪费的CPU时间)明显优于这些算法。更多还原

【Abstract】 Temporal data object accessed by transactions of real-time database systems has been applied in diverse domains.However,almost all of the current algorithms of transaction scheduling only take logic consistency of object into account ,while ignoring temporal consistency.First,this paper presents the concept of temporary data deadline,and proves the feasibility of low-cost predictive algorithm in form of theorem in order to abort or postpone those transactions that cannot satisfy temporal consistency as soon as possible,therefore,computation resources are saved to accommodate for other transactions.Next,by exploiting data semantics,the algorithm improves scheduling performance combined with predictive algorithm.A new transactional scheduling algorithm with temporal constraints,called PSBA,is proposed based on these strategies in this paper.The simulation results show that performance of the algorithm significantly outperforms that of well-known algorithms so far.更多还原