Oracle International Corporation

Other

Benedicto Elmo Garin, Jr

Mahesh Baburao Girkar

Raymond Guzman

Yunrui Li

Vinay H Srihari

Douglas Andrew Voss

Stephen John Vivian

George H Claborn

Steve Lee

Jiangbin Luo

Sadhana Kyathappala

Steven Taihung Lee

Jia Shi

Wei Ming Hu

Vsevolod Panteleenko

Jin-Jwei Chen

Theocharis Kampouris

Michael Jennings

A method, system and computer program product for low loss database backup and recovery. The method commences by transmitting, by a first server to a third server, a copy of a database snapshot backup, the transmitting commencing at a first time. Then capturing, by the first server, a stream of database redo data, the capturing commencing before or upon transmitting the database snapshot backup, and continuing until a third time. The stream of database redo data is received by an intermediate server after which the intermediate server transmits the stream of database redo data to the third server. Now, the third server has the database snapshot backups and the database redo data. The third server can send to a fourth server all or portion of the database redo data to be applied to the copy of the database snapshot backup restored there to create a restored database.

Zero and near-zero data loss database backup and recovery

A method and system is provided for reducing delay to applications connected to a database server that guarantees no data loss during failure or disaster. After storing a log record persistently in a local primary log, the log writer returns control to the application which continues running concurrently with the database server sending the session's log records to a standby database. A separate back channel is used by the standby to communicate, out-of-band to the primary, the location of the last log record stored persistently to the standby log. An application waiting for a transaction to commit may wait until the transaction's commit record has been persisted. Also described is a technique for reducing application delay when there is contention between nodes of a multi-node cluster for updating the same block. The technique provides for an asynchronous ping protocol that guarantees zero data loss during failure or disaster.

Method for maximizing throughput and minimizing transactions response times on the primary system in the presence of a zero data loss standby replica

A method and system is provided for measuring, guaranteeing, and reducing replication data lag time between a primary system and one or more standby systems. Each standby system determines the lag time between the generation of a consistent version of data on the primary system and the time that the consistent version is applied on the standby system. Applications can request and be guaranteed to receive data from a standby system that is identical to the state on the primary system at the time of the query, or lag the primary state only by a maximum tolerable amount. A standby system may also publish a service that guarantees a maximum lag time and withdraw the service offer when the actual lag time exceeds the guaranteed lag time. Implications for implementing synchronous and asynchronous replication as well as performance optimizations are also discussed.

Controlling data lag in a replicated computer system

A method and apparatus for detecting split brain in a distributed system is provided. After determining that a rogue instance is no longer an active member of the cluster, a recovery instance detects activity associated with a redo log that is updated by the rogue instance to store log records that describe changes made by the rogue instance to data associated with the cluster.

Methods for detecting split brain in a distributed system

Techniques used in an automatic failover configuration having a primary database system, a standby database system, and an observer. 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 may use asynchronous transfer modes to transfer redo to the standby and permits automatic failover only when the observer is present and the failover will not result in data loss due to the asynchronous transfer mode beyond a specified maximum. 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.

Reinstatement of database systems in an automatic failover configuration

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.

Automatic failover configuration with lightweight observer

Reinstatement of database system in an automatic failover configuration

Automatic failover configuration with redundant abservers

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Hudson, NH, United States of America

Benedicto Elmo Garin, Jr