实时主动数据库并发控制协议

提出了实时主动数据库系统实时多版本两阶段封锁并发控制协议(RTMV2PL). 该协议将多版本并发控制的优点和两阶段封锁并发控制机制优点结合起来. 多版本两阶段封锁机制消除了只读事务和更新事务的冲突, 只读事物从不重启动. 对实时主动数据库系统的事务优先级重新定义. 通过模拟仿真与传统的HP2PL和OCC-TI-WAIT-50协议进行比较. 研究结果表明, 并发控制协议不但能有效地降低事务的重启动率和延误截止时间率, 而且提高只读事物的响应时间. 当事务触发率高, 导致系统负载高时, 它的性能仍比其他协议的性能好.

A concurrency control protocol in real-time active database systems

Real-time multiversion two-phase locking(RTMV2PL) concurrency control protocol was presented for real-time active database systems(RTADBSs).The protocol presented combines the advantages of multiversion concurrency control mechanism with the advantages of two phase locking.Multiversion two-phase locking mechanism eliminates the conflicts between read-only and update transactions.Read-only transactions are never restarted.The priority of transactions is redefined for RTDAbss.The protocol presented is compared with concurrency control HP2PL and OCC-TI-WAIT-50 protocol by simulation experiments.The simulation results show that the new protocol can not only effectively reduce the miss rate of transactions and the restart rate of transactions,but also significantly improve the response time of read-only transactions.When transaction triggering probability is higher,which results in increasing system load,RTMV2PL still performs better than other protocols.