摘要
实时数据库系统（ＲＴＤＢＳＲｅａｌＴｉｍｅＤａｔａｂａｓｅＳｙｓｔｅｍ）必须满足事务的时间限制，同时又能保持数据一致性。本文介绍一个以优先级驱动的封锁协议———综合实时封锁协议。这个协议可以避免死锁，而且高优先级事务不会被未提交的低优先级事务阻塞。这个协议不需要事先知道事务对数据的请求和事务执行时间，因此有很广的适应性。在数据库原型环境中，这个协议会比两步封锁协议（２ＰＬＴｗｏＰｈａｓｅＬｏｃｋｉｎｇ）性能更好。
atabase systems for realtime application must satisfy timing constraints associated with transactions in addition to maintaining the consistency of data. In this paper, we examine a prioritydriven locking protocol called the integrated realtime locking protocol. We show that this protocol is free of deadlock and in addition a high priority transaction is not blocked by uncommitted lower priority transactions. The protocol does not assume any knowledge about the data requirements or the execution time of each transaction. This makes the protocol widely applicable since in many actual environments, such information may not be readily available. Using a database prototyping environment, the proposed protocol offers performance improvement on the twophase locking protocol.
