Oracle International Corporation

George H Claborn

Stephen John Vivian

Mahesh Baburao Girkar

Raymond Guzman

Douglas Andrew Voss

Steve Lee

Benedicto Elmo Garin, Jr

Lee B Barton

Jiangbin Luo

Benedito Elmo Garin, Jr

Vinay H Srihari

William E Fisher

James Stenoish

Robert McGuirk

Robert R McGulrk

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

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.

Database system configured for automatic failover with user-limited data loss

Techniques for transferring objects between database systems. A transfer is controlled by a master table in the RDBMS that is performing the transfer operation. The master table specifies the kind of transfer operation to be performed, a set of objects to be transferred, operations to be performed on the objects as they are being transferred, and filters for selecting a subset of the objects. During execution of the transfer, the transfer mechanism maintains and updates state in the master table and thereby makes it possible for the entity that is doing the transfer to determine the current status of the transfer and to restart the transfer after it has been stopped. The entity that is performing the transfer may also detach from the transfer without stopping the transfer and later again attach to the transfer.

Apparatus and methods for transferring database objects into and out of database systems

Database system configured for automatic failover with no data loss

Techniques for simplifying the aggregation of data stored in a number of objects in a database system. A user-defined type and an object view are associated with a kind of data to be aggregated. The object view specifies the locations of the data in the objects and maps the data to be aggregated into the user-defined type. An application program interface includes a fetch interface that causes the database system to make a query over the object view associated with the kind of data and return the aggregated data in a set of objects of the user-defined type. The returned data is converted to XML and may be further transformed using XSL stylesheets. The application program interface further includes a filter interface that specifies a restriction for the query, a count interface that specifies the number of objects to be returned at once by the application program interface, a transform interface that specifies an XSL style sheet, and a transform parameter interface for providing parameters to the XSL style sheet. The techniques may be used to aggregate metadata for various classes of objects from a data dictionary in a database system. In this application, each class of object has a name and a user-defined type and object view are associated with the class name. The fetch interface specifies a class name and the user-defined type and object view associated with the name are used to aggregate the metadata. One of the transforms performed in this application is the transformation of the metadata for an object into creation DDL for the object.

Aggregating and manipulating dictionary metadata in a database system

Growing community of inventors

Amherst, NH, United States of America

George H Claborn