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为在广播环境中同时有效支持移动更新事务和移动只读事务,提出一种可在移动客户端同时支持更新事务和只读事务的伪可串行化实时并发控制协议。形式化定义了伪可串行化,证明了伪可串行化比冲突可串行化宽松且能始终保证数据库的一致性,给出了保证伪可串行化的充分必要条件。基于时标段排序原理,提出了相应的实时并发控制协议。通过性能评价实验验证了新协议的性能。实验结果表明,新协议可显著改进移动事务的平均响应时间。
To effectively support both mobile update transactions and mobile read-only transactions in a broadcast environment, a pseudo-serializable real-time concurrency control protocol that supports both update transactions and read-only transactions on a mobile client is proposed. The pseudo-serialization is formally defined. It is proved that the pseudo-serializable ratio conflict can be serialized and relaxed, and the consistency of the database can be guaranteed at all times. The sufficient and necessary conditions for guaranteeing pseudo-serialization are given. Based on the time-series sorting principle, a corresponding real-time concurrency control protocol is proposed. The performance of the new protocol is verified through performance evaluation experiments. Experimental results show that the new protocol can significantly improve the average response time of mobile transactions.