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:
Dec. 01, 2009
Filed:
Nov. 22, 2006
George H. Claborn, Amherst, NH (US);
Stephen John Vivian, Londonderry, NH (US);
Robert R. Mcguirk, Nashua, NH (US);
Mahesh Baburao Girkar, Cupertino, CA (US);
Benedito Elmo Garin, Jr., Hudson, NH (US);
Raymond Guzman, Amherst, NH (US);
Douglas Voss, Nashua, NH (US);
George H. Claborn, Amherst, NH (US);
Stephen John Vivian, Londonderry, NH (US);
Robert R. McGuirk, Nashua, NH (US);
Mahesh Baburao Girkar, Cupertino, CA (US);
Benedito Elmo Garin, Jr., Hudson, NH (US);
Raymond Guzman, Amherst, NH (US);
Douglas Voss, Nashua, NH (US);
Oracle International Corporation, Redwood Shores, CA (US);
Abstract
Techniques used in an automatic failover configuration having a primary database system, a standby database system, and an observer for preventing divergence among the primary and standby database systems while increasing the availability of the primary database system. In the automatic failover configuration, the primary database system remains available even in the absence of both the standby and the observer as long as the standby and the observer become absent sequentially. The failover configuration further permits automatic failover only when the observer is present and the standby and the primary are synchronized and inhibits state changes during failover. The database systems and the observer have copies of failover configuration state and the techniques include techniques for propagating the most recent version of the state among the databases and the observer and techniques for using carefully-ordered writes to ensure that state changes are propagated in a fashion which prevents divergence.