对象库的并发控制

本文提出了适于工程设计环境的并发控制技术－－动态确认并发控制模式。与传统商业应用相比,该环境中的事务持续时间一般很长,因此它需要新的并发控制技术。动态确认是乐观的并发控制模式,避免了对数据长时间的上锁。它产生的操作是“关于数据库可串行化的”,即认为只要产生相同结果,则该调度就和从同一初始数据库状态开始执行的事务串行操作等价。显然,这个串行化标准是弱于通用串行化标准的。

CONCURRENCY CONTROL FOR OBJECT BASES

This paper presents concurrency control techniques suitable for engineering design environments. Transactions in a design application are usually Very long compared with those in tradional applications. We present the dynamic validation concurrency control scheme, an optimistic concurrecy control scheme that avoids locking data items for extented periods of time. Dynamic validation enforces executions that are "serializable with respect to the database state". This correctness.criterion relaxes the classical serial criterion, and allows schedules that are equivalent, i. e. produces the same effect, to a serial execution of transaction starting from the same initial database state.