Oracle International Corporation

Robert McGuirk

Mahesh Baburao Girkar

Juan R Loaiza

Nitin Karkhanis

Steve Lee

Jiangbin Luo

Benedicto Garin

Hongjie Yang

Steven McGee

Michael Harvey

Raymond Guzman

Douglas Andrew Voss

Stephen John Vivian

George H Claborn

Benedito Elmo Garin, Jr

Disclosed are methods and apparatuses to provide a redo repeater that allows for no data loss protection without the performance impact to the primary database even when a significant geographical distance separates the primary and standby databases. The Repeater is a lightweight entity that receives redo from the primary database with the purpose of redistributing that redo throughout the primary/standby system configuration. The Repeater able to extend no data loss protection and switchover functionality to terminal standby databases even though the primary database does not need to have a direct connection with those destinations.

Method and system for implementing a redo repeater

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.

Database system configured for automatic failover with no data loss

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Nashua, NH, United States of America

Robert McGuirk