PARALLELIZED REDO-ONLY LOGGING AND RECOVERY FOR HIGHLY AVAILABLE MAIN MEMORY DATABASE SYSTEMS

摘要

A parallel logging and recovery scheme for highly available main-memory database systems is presented. A preferred embodiment called parallel redo-only logging ("PROL") combines physical logging and selective replay of redo-only log records. During physical logging, log records are generated with an update sequence number representing the sequence of database update. The log records are replayed selectively during recovery based on the update sequence number. Since the order of replaying log records doesn't matter in physical logging, PROL makes parallel operations possible. Since the physical logging does not depend on the state of the object to which the log records are applied, the present invention also makes it easy to construct a log-based hot standby system.