Hitachi, Ltd.

Hitachi Software Engineering Company, Ltd.

Junko Katsumata

Kota Yamaguchi

Nobuo Kawamura

Hiroshi Yamakawa

Shigetoshi Hayashi

Yasuhiro Kamada

Keisuke Toda

Taichi Ishikawa

If relocation of a table with a high reference frequency is made possible, the database management method and system are arranged to improve performance according to the number of increased nodes and accumulate a reference frequency of each external storage unit allocated to each database management node. A data storage area for storing the table with a high reference frequency, located in the external storage unit, is specified as a shared data area to be referenced by plural nodes. The system is controlled to cause the nodes to refer to the shared table stored in the shared data area on any timing in parallel. This prevents load from being concentrated onto the node allocated to the data area.

Data processing system and method with data sharing for the same

When a database area multi-written or replicated in an external storage unit is separated, a database management system writes consistent data into the external storage unit. A method and system capable of controlling a timing of separating the replicated database area is provided. Furthermore, new data directory information necessary to access the replicated database is dynamically added based on the data directory information of the replication source database. A method and system capable of selecting whether to access the database which is the source of the replication or access the replicated database are provided. Thus, when the database area multi-written or replicated in an external storage unit is separated and physical replicated databases are created, it is possible to maintain consistency of the replicated databases while continuing transaction processing.

Method and system of database management for replica database

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Yokohama, Japan

Junko Katsumata