High speed, non-log based database recovery technique

摘要

A technique for recoving a database having intrinsic versioning and no logging mechanism is described. The process allows the information storage and retrieval system to recover from crashes in very short times irrespective of the size and complexity of the data objects contained in the database. The recovery process does not require an update or transaction log, consequently all the delays associated with keeping a log, such write time to a log and log truncation during recovery are avoided. The most recent stable object table in the database is identified in a non-persistent memory storage area. An allocation map is then used to identify unstable data in the non-persistent memory area. The unstable data is then scanned to build a post-recovery object table. By performing this scan before a database crash or failure, a recovery can be performed without having to scan the non-persistent or the persistent memory areas of the information storage and retrieval system. In addition, a conventional transactional log file need not be maintained for the database to recover.