2005•Journal of Central South University of Technology(Natural Science)Requires access
A concurrency control protocol in real-time active database systems
Yuan Xiaoli
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Abstract
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.