In parallel real-time database systems, concurrency control protocols must satisfy time constraints as well as the integrity constraints. The authors present a validation concurrency control(VCC) protocol, which can e...In parallel real-time database systems, concurrency control protocols must satisfy time constraints as well as the integrity constraints. The authors present a validation concurrency control(VCC) protocol, which can enhance the performance of real-time concurrency control mechanism by reducing the number of transactions that might miss their deadlines, and compare the performance of validation concurrency control protocol with that of HP2PL(High priority two phase locking) protocol and OCC-TI-WAIT-50(Optimistic concurrency control-time interval-wait-50) protocol under shared-disk architecture by simulation. The simulation results reveal that the protocol the author presented can effectively reduce the number of transactions restarting which might miss their deadlines and performs better than HP2PL and OCC-TI-WAIT-50. It works well when arrival rate of transaction is lesser than threshold. However, due to resource contention the percentage of missing deadline increases sharply when arrival rate is greater than the threshold.展开更多
提出了一种含有实时和非实时两部分的混合实时事务接纳控制机制ACMHRTT(Admission Control Mech-anism for Hybrid Real-Time Transactions)。ACMHRTT将混合事务分为真实时和非实时两部分,综合考虑混合事务的执行需求和价值,目的是为保...提出了一种含有实时和非实时两部分的混合实时事务接纳控制机制ACMHRTT(Admission Control Mech-anism for Hybrid Real-Time Transactions)。ACMHRTT将混合事务分为真实时和非实时两部分,综合考虑混合事务的执行需求和价值,目的是为保留系统资源,有效控制负载,减少了被系统接纳执行后而又不能满足截止期的事务,提高实时数据库系统事务处理的成功率和可靠性,使系统收益最大化。着重分析了ACMHRTT的模型,对ACMHRTT与传统的ACM作了分析比较,说明了比传统的ACM协议更优,并提出了须进一步研究的问题。展开更多
文摘In parallel real-time database systems, concurrency control protocols must satisfy time constraints as well as the integrity constraints. The authors present a validation concurrency control(VCC) protocol, which can enhance the performance of real-time concurrency control mechanism by reducing the number of transactions that might miss their deadlines, and compare the performance of validation concurrency control protocol with that of HP2PL(High priority two phase locking) protocol and OCC-TI-WAIT-50(Optimistic concurrency control-time interval-wait-50) protocol under shared-disk architecture by simulation. The simulation results reveal that the protocol the author presented can effectively reduce the number of transactions restarting which might miss their deadlines and performs better than HP2PL and OCC-TI-WAIT-50. It works well when arrival rate of transaction is lesser than threshold. However, due to resource contention the percentage of missing deadline increases sharply when arrival rate is greater than the threshold.
文摘提出了一种含有实时和非实时两部分的混合实时事务接纳控制机制ACMHRTT(Admission Control Mech-anism for Hybrid Real-Time Transactions)。ACMHRTT将混合事务分为真实时和非实时两部分,综合考虑混合事务的执行需求和价值,目的是为保留系统资源,有效控制负载,减少了被系统接纳执行后而又不能满足截止期的事务,提高实时数据库系统事务处理的成功率和可靠性,使系统收益最大化。着重分析了ACMHRTT的模型,对ACMHRTT与传统的ACM作了分析比较,说明了比传统的ACM协议更优,并提出了须进一步研究的问题。
