Patent ID: 6584477
Filing Date: 2003-06-24
Classification: G06F,Y10S

Abstract:
A method of operating a backup system so as to replicate database updates performed on a primary system, the method comprising:receiving a stream of audit records from the primary system, the audit records including audit update records and audit backout records indicating database updates and database backouts generated by transactions executing on the primary system; storing the audit update records and audit backout records in one or more image trails; and for each image trail, sequentially applying to a backup database the database updates and backouts indicated by the audit update records and audit backout records in the image trail, in the order the audit update records and audit backout records are stored in the image trail and without regard to whether corresponding transactions in the primary system committed or aborted; upon the occurrence of a predefined event, determining a set of primary system transactions for which a commit/abort outcome is unknown; and for each image trial, undoing database updates for the transactions for which the commit/abort outcome has been determined to be unknown.