Abstract: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.