Oracle International Corporation

Mahesh Subramaniam

James William Stamos

Wayne Smith

Curtis Elsbernd

Jing Liu

Subramanian Muralidhar

Lik Wong

Dieter Gawlick

Lakshminarayanan Luxi Chidambaran

Debashis Saha

Nimar Singh Arora

Debashish Chatterjee

Alan Robert Downing

Alan J Demers

Benny Souder

Edwina Lu

Harry Sun

John C Graham

Jim Stamos

Joan Loaiza

Techniques for authenticating users when an operation requested by a user in one of the systems of a distributed system is redirected to another system of the distributed system. The user is authenticated in the usual way to the one system but is authenticated to the other system for the redirected operation by an authentication proxy in the first system. The fact that the authentication proxy is providing a redirected operation means that the user who requested the operation has been authenticated to the one system. The other system is thus able to authenticate the user for the redirected operation with different authentication information than would otherwise be required. An example of how the techniques are used is a distributed database system where one of the database systems in the distributed system is a cache for another of the database systems.

Authenticating sessions in queryable caches

An approach is provided to automatically resolve conflict between instantiation and ongoing data replication operations. In an embodiment, incremental change records that describe one or more database operations are received at a sink entity. Here, all of the one or more database operations have occurred in a second database after a particular time. A first database operation in the one or more database operations to a particular row in the first database is applied. When a conflict with a second database operation that operates on the particular row is detected, one or more compensating actions, which may, but are not limited to, be a different database operation and/or an operation that creates a conflict log entry, may be performed. Here, the second database operation has occurred in the second database prior to the particular time. When the second database operation is to be performed, an appropriate operation may be performed.

Automatic error correction for replication and instantaneous instantiation

Techniques are provided for creating object-oriented materialized views. The object-oriented materialized views may be object materialized views or object-relational materialized views. The base tables may be object tables, object relational tables, or relational tables. The object-oriented materialized views may be refreshed, fully or incrementally. When an object-oriented materialized view is created, refresh code is generated for it. Through the use of object-oriented materialized views, users gain both the efficiency of materialized views and the power of the object-oriented paradigm.

Object-oriented materialized views

A method and system are provided for instantiating objects for participation in information sharing relationships. According to one technique, a copy of an object is made, where the copy includes all changes made prior to a particular point in time, and no changes made after the particular point in time. The copy is used to create a second object. Data that reflects the particular point in time is stored, and subsequently used to determine which changes should be applied to the second object. Data that indicates that the creation time of the second object is stored, and subsequently used to determine which changes should be applied to the original object.

Instantiation of objects for information-sharing relationships

Techniques are disclosed for sharing information in a wide variety of contexts. An information sharing system is described that allows both an explicit capture process and an implicit capture process to add information items to a staging area. Further, the information sharing system supports both implicit and explicit consumption of information items that are stored in said staging area. A rules engine is provided to allow users to create and register rules that customize the behavior of the capture processes, the consuming processes, and propagation processes that propagate information from the staging areas to designated destinations. Techniques are also described for achieving exactly-once handling of sequence of items, where the items are maintained in volatile memory. Techniques are also provided for recording DDL operations, and for asynchronously performing operations based on the previously-performed DDL operations.

Replicating DDL changes using streams

Techniques are provided for allowing the reorganization and/or redefinition of data in a relational database with minimal or no downtime by allowing 'online' reorganization/redefinition of the data. According to one aspect of the invention, an empty revised table is created in the same schema as the target table. The revised table is created with the attributes that are desired for the reorganization/redefinition of the target table. Triggers, constraints, grants and indexes that are associated with the target table are replicated for the revised table. The reorganization/redefinition is performed by using an underlying mechanism that involves using incrementally maintainable materialized views. According to one feature, the revised table is initialized and periodically synchronized with the target table. After the reorganization and/or redefinition is complete on the revised table, the revised table and the target table switch identities such that the revised table is now the target table and the target table becomes the revised table.

Online reorganization and redefinition of relational database tables

Techniques used in a distributed database system for simplifying copying of objects from one database system in the distributed database system to another and establishing the infrastructure necessary for the distributed system in the database systems. One application of the techniques is setting up a cache database system that has a subset of the objects in another database system and establishing a link for redirecting misses between the cache and the other database system. Also included is the infrastructure in the cache and the other database system for an authentication proxy that establishes sessions in the other database system for users to perform operations that have been redirected as a result of a miss in the cache. The techniques require only that the user supply simple descriptions of some of the objects to be copied; the techniques locate the necessary dependent objects and make objects for the infrastructure. Some of these are descriptions of the infrastructure objects that are copied to the cache and executed there and others are objects that are added directly to the other database system.

Instantiating objects in distributed database systems

Replication for front office automation involves the use of snapshots that are instantiated on laptops, in which refreshing the snapshots is driven from a master site with a high-performance protocol. All of the necessary snapshot metadata for performing the snapshot refreshes is stored at the master site, so that the laptop only needs to send a single refresh request. In response to the refresh request, the master site reconciles the differences between the master tables and the laptop's snapshots and transmits the differences to the laptop, reducing the necessary network traffic for updating a snapshot to a single round trip.

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Foster City, CA, United States of America

Mahesh Subramaniam