HIGH SPEED ON-LINE BACKUP WHEN USING LOGICAL LOG OPERATIONS

A database computer system and a high speed method for backup is provided for use when general logical operations are logged. Data is copied from the active stable database to a backup database while update activity continues. The stable database is divided into disjoint partitions, and backup progress is independently tracked in each partition. For each partition in which backup progress is to be tracked independently, two boundary values are maintained that separate objects into categories of pending, backed up, or in doubt. To permit backup to proceed with little synchronization between it and the cache manager, backup reports its progress only from time to time. Depending on system tuning considerations, the reporting can be made more or less precise by varying the granularity of the steps in which backup progress is reported.