一种实时动态数据库故障恢复策略

A Real-Time Dynamic Database Crash Recovery Strategy

分布式实时内存数据库通常使用在时间关键型应用中,对这些应用而言,故障后能迅速而有效地恢复是至关重要的.首先通过分析分布式实时内存数据库故障恢复需求,给出了其恢复正确性准则.然后提出了一种基于日志的实时动态故障恢复模式RTDCRS(real-time dynamic crash recovery scheme),并证明了其正确性.RTDCRS采用了集成分区日志和短暂日志特性的实时日志模式,同时使用非易失性高速存储设备作为日志存储区,以尽可能地降低系统正常运行时日志代价.在站点故障后的恢复策略上,给出了基于分类恢复思想的动态恢复策略,以尽可能地减少故障站点停止服务的时间.性能测试结果显示,RTDCRS在事务错过截止期比率和站点停止服务时间两方面与传统的故障恢复模式相比具有明显的优越性.

Distributed real-time main memory databases are usually applied in some time-critical applications. For these applications, rapid and efficient recovery in the event of site crash is very important. Firstly, through analyzing the recovery requirements of failure in distributed real-time main memory databases, the recovery correctness criteria of distributed real-time main memory database are presented. Then, a real-time dynamic crash recovery scheme based on log （RTDCRS） is presented, and the correctness of RTDCRS is proved. RTDCRS adopts the real-time logging scheme integrating the characteristics of partitioned logging, ephemeral logging and uses nonvolatile high-speed store as logging storage area in order to reduce the logging cost during the normal running. After a site crash, a dynamic recovery strategy based on classification recovery idea is adopted to decrease the downtime. Performance tests and evaluations results show that RTDCRS has better performances than the traditional recovery schemes in two aspects： The missing deadlines ratio of transactions and the time of system denying services after crashes.