Oracle International Corporation

Elizabeth Davis

Gianfranco Putzolu

Andre Kruglikov

A method and apparatus for multi-phase locking for partition maintenance operations is provided. In the first phase, a shared data dictionary lock is acquired on a body of metadata in a data dictionary. Next, the data dictionary is read and a list of affected partitions is generated. In the second phase, an intent exclusive data lock is acquired on the affected table. Next, an exclusive data lock is acquired on the affected partitions of the affected table. The shared data dictionary lock on the data dictionary is released and a physical attribute of the data of the affected partitions is changed. In the third phase, an exclusive data dictionary lock is acquired on the data dictionary. The metadata associated with the affected partitions in the data dictionary is updated and the exclusive data locks on the affected partitions and the intent exclusive data lock on the affected table are released. Finally, the exclusive data dictionary lock on the data dictionary is released. As a result of performing multi-phase locking for partition maintenance operations, the scope of resources locked is reduced and the efficiency of the partition maintenance operations, from a concurrency point of view, is increased.

Multi-phase locking for partition maintenance operations

A method and apparatus for multi-phase locking for partition maintenance operations. In the first phase, a shared data dictionary lock is acquired on a body of metadata in a data dictionary. Next, the data dictionary is read and a list of affected partitions is generated. In the second phase, an intent exclusive data lock is acquired on the affected table. Next, an exclusive data lock is acquired on the affected partitions of the affected table. The shared data dictionary lock on the data dictionary is released and a physical attribute of the data of the affected partitions is changed. In the third phase, an exclusive data dictionary lock is acquired on the data dictionary. The metadata associated with the affected partitions in the data dictionary is updated and the exclusive data locks on the affected partitions and the intent exclusive data lock on the affected table are released. Finally, the exclusive data dictionary lock on the data dictionary is released. As a result of performing multi-phase locking for partition maintenance operations, the scope of resources locked is reduced and the efficiency of the partition maintenance operations, from a concurrency point of view, is increased.

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Elizabeth Davis