High Speed On-line Backup When Using Logical Log Operations

Media recovery protects a database from failures of the stable medium by maintaining an extra copy of the database, called the backup, and a media recovery log. When a failure occurs, the database is “restored” from the backup, and the media recovery log is used to roll forward the database to the desired time, usually the current time. Backup must be both fast and “on-line”, i.e. concurrent with on-going update activity. Conventional online backup sequentially copies from the stable database, almost independent of the database cache manager, but requires pageoriented log operations. But results of logical operations must be flushed to a stable database (a backup is a stable database) in a constrained order to guarantee recovery. This order is not naturally achieved for the backup by a cache manager concerned only with crash recovery. We describe a “full speed” backup, only loosely coupled to the cache manager, and hence similar to current online backups, but effective fo...

• Type: Conference
• Year: 2000
• Where: SIGMOD
• Authors: David B. Lomet
• Keywords: Cache Manager, Database, Media Recovery Log, SIGMOD 2000, Stable Database