Accommodating logical logging under fuzzy checkpointing in main memory databases

This paper presents a simple and effective method to reduce the size of log data for recovery in main memory databases. Fuzzy checkpointing is known to be very efficient in main memory databases due to asynchronous backup activities. By this feature, most recovery works in the past have used only physical logging schemes. Since the size of physical log records is quite large, physical logging schemes cause the recovery time to be much longer than that using logical logging schemes. We propose a hybrid logging method that can accommodate logical logging under fuzzy checkpointing. This method significantly decreases the size of log data, and hence speeds up the recovery time. We also propose a reapplying rule in segmented MMDB, which reduces the number of log records for recovery. We evaluate the performance of the proposed methods through analytic analyses. The results show that we can reduce the size of log data to more than half, compared with those that use only physical logging.