The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 19, 1999
Filed:
Oct. 26, 1995
Michael E Habben, Issaquah, WA (US);
Microsoft Corporation, Redmond, WA (US);
Abstract
A system for generating a gapless series of identity values in a history log maintained in a database by a database management system without adversely impacting database performance. The system comprises the steps of determining a last used identity value independent of an intervening disruptive event that is disruptive to the database management system, generating a next identity value based on the last used identity value, and inserting a record of an event into the history log wherein a change record event contains the next identity value. Determining the last used identity value in the history log depending on whether or not a disruptive event has occurred during normal transaction processing. Absent a disruptive event, the last used identity value is the identity value used in the most recent change record insertion. In the event of a disruptive event, the last used identity value is retrieved from the last change record of the last committed transaction in the history log as the database recovery phase traverses the history log to identify committed transactions for reapplication and incomplete transactions for rollback to bring the database to a consistent state.