Abstract: A method and apparatus for updating databases are disclosed. An update vector for an object is created for identifying updated attributes. A dependent object is identified and a dependency vector of the dependent object is compared with update vector to determine whether the dependent object depends on the updated attributes.

Abstract: A standby database system or another replica data system replicates changes, made to data blocks at a source database system or another primary data copy, to replicas of the data blocks at the standby database system or other replica. While replicating the changes to the data blocks thereof, the standby database system (or other replica) receives queries (or reads) issued thereto and computes the queries based on data read from the data blocks thereof.

Abstract: A standby database system or another replica data system replicates changes, made to data blocks at a source database system or another primary data copy, to replicas of the data blocks at the standby database system or other replica. While replicating the changes to the data blocks thereof, the standby database system (or other replica) receives queries (or reads) issued thereto and computes the queries based on data read from the data blocks thereof.

Abstract: A database may facilitate zero-downtime upgrades by concurrently maintaining multiple editions of database objects for use by both pre-upgrade and post-upgrade clients of a database application. Operations performed within the database are associated with an edition based on, for example, an initiating client or transaction. When an operation references an object or data, the database automatically performs the operation using the object or data associated with the edition with which the operation is itself associated. The database may determine the associated edition without explicit identification of the associated edition in a query or in code. Thus, no client or stored procedure code changes are necessary to reflect a new edition added during an update. Data changes in one edition may be automatically and immediately propagated to the other edition through the use of cross-edition triggers, thereby allowing both pre-upgrade and post-upgrade clients to remain fully functional throughout an upgrade.

Abstract: A method and system for using a requeueing procedure to resolve deadlocks in a computing system is disclosed. A request for a resource may be requeued after a designated period of time or wait cycles if it is blocked from being granted. For example, a request for exclusive ownership of a resource could be requeued if it cannot be granted within an appropriate period of time. These types of requests are requeued to allow other requests for the same resource to move ahead in the wait queue. This allows other grantable requests behind the blocked request to be immediately granted. Using this approach, it is possible that allowing the other requests behind the timed-out request to move ahead in the queue will set off a chain reaction of accesses to resources which will clear the deadlock situation that initially causes the requeued request(s) to be blocked.

Abstract: A method and apparatus for updating databases are disclosed. An update vector for an object is created for identifying updated attributes. A dependent object is identified and a dependency vector of the dependent object is compared with update vector to determine whether the dependent object depends on the updated attributes.

Abstract: Versioned metadata allows multiple versions of metadata for a given object to exist concurrently on a system thereby supporting the parallel execution of operations which would otherwise be mutually exclusive. Metadata updates are permitted while other objects maintain access to another version of the metadata through a versioning infrastructure. The versioning infrastructure allows the creation of new versions of metadata, maintains obsolete versions in the system as long as they are being used by any object, and deletes the obsolete versions once they are no longer in use.

Abstract: A method and system for using a requeueing procedure to resolve deadlocks in a computing system is disclosed. A request for a resource may be requeued after a designated period of time or wait cycles if it is blocked from being granted. For example, a request for exclusive ownership of a resource could be requeued if it cannot be granted within an appropriate period of time. These types of requests are requeued to allow other requests for the same resource to move ahead in the wait queue. This allows other grantable requests behind the blocked request to be immediately granted. Using this approach, it is possible that allowing the other requests behind the timed-out request to move ahead in the queue will set off a chain reaction of accesses to resources which will clear the deadlock situation that initially causes the requeued request(s) to be blocked.