A Real-time Concurrency Control Protocol Using Dynamical Adjustment of Serialization Order

Real-time concurrency control protocol,which used to isolate the interference of concurrent transactions in real-time database,is needed to achieve consistency.A four phase′s real-time concurrency control protocol which is called HTRCC-DASO is proposed.In reading or waiting phase,the serialization order of transactions is dynamically adjusted based on their priority.High priority is allowed to commit earlier and the restart overhead of aborted transactions is reduced by blocking or restart low-priority transactions as soon as possible.In validation phase,the exterior and mutual consistency of read and write set of transaction are checked and timestamp interval of all transactions at reading or waiting phase is adjusted to satisfy the requirements of temporal consistency and conflict serializability.In order to achieve better real-time performance,an enhanced HTRCC-DASO,called SHTRCC-DASO is proposed by introducing the concept of similarity.Performance tests show that SHTRCC-DASO can ensure very well real-time performance.