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:
Jun. 09, 1998
Filed:
Sep. 01, 1995
David Lomet, Westford, MA (US);
Betty Salzberg, Newton, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
Modern database systems provide media recovery by taking periodic backups and applying a transaction log to the backup to bring the data up-to-date. A multi-versioned database is one that retains and provides access to historical versions of data. The present invention shows how a history database, supported by the Time-Split B-tree, can be used to also provide the backup function of media recovery. Thus, the same versions used for database history are used for database backup. The cost of taking a backup is comparable to the cost of a good differential backup method, whereby only changed data is backed up. The media recovery cost, especially when the media failure is only partial, e.g., a single disk page, will frequently be lower.