嵌入式混合型实时事务并发控制研究

Research on embedded hybrid real-time transaction concurrency control

针对嵌入式混合型实时事务并发控制新特点,引入替代和补偿,提出一种混合型并发控制算法,即无冲突混合并发控制MCC-CCCP算法.该算法将冲突分为类内和类间两种,利用ET-CCCP和CCCP协议分别解决硬实时事务类内和软实时事务类内的冲突;设计的LC-CCCP算法通过比较选出冲突数量最少的替代参与到并发控制中,同时采取一定的补偿措施降低冲突数量,以解决不同类间冲突.模拟实验表明,该混合型算法降低了事务重启率和错失率,具有一定的优越性.

Based on new characters of embedded hybrid real-time transaction concurrency control,a hybrid concurrency control algorithm,namely mixed concurrency control-CCCP（ MCC-CCCP）,was proposed by adding substitution and compensation. Conflict was divided into the intra-class and inter-class in the algorithm. ET-CCCP protocol solved the intra-class conflict of hard real-time transaction,while CCCP protocol solved the intra-class conflict of soft real-time transaction. The LC-CCCP algorithm was designed to resolve the inter-class conflicts by comparing to select the least number of alternative involved in the concurrency control and taking some compensation measures to reduce the number of conflicts. Simulation experiments showed that the hybrid algorithm decreased the rate of restart and transaction miss,which had certain advantages.