Patent ID: 6185577
Filing Date: 2001-02-06
Classification: G06F,Y10S

Abstract:
A method for performing incremental undo when recovering a computer database from a failure, the method comprising:storing changes for a plurality of data blocks in a single undo record;establishing as a current rollback entry, a rollback entry that belongs to a plurality of rollback entries within said single undo record, said plurality of rollback entries corresponding to a particular data block in said plurality of data blocks;examining a status flag corresponding to said current rollback entry to determine whether said current rollback entry has been applied;establishing a next rollback entry in said plurality of rollback entries as said current rollback entry without applying said current rollback entry when said current rollback entry has been applied; andwhen said current rollback entry has not been applied, then:retrieving said current rollback entry from said plurality of rollback entries;applying one or more changes indicated by said current rollback entry to said particular data block; andsetting said status flag in said undo record to indicate said current rollback entry has been applied.