Hitachi, Ltd.

Hitachi Software Engineering Company, Ltd.

Mitsuo Miyazaki

Hiroshi Yamakawa

Kota Yamaguchi

Kenichi Kitamura

Nobuo Kawamura

Norihiro Hara

Kazuo Masai

Katsushi Yako

Masataka Kan

Kuniaki Yamashita

Hiroshi Takayama

There is provided a technique capable of executing a predetermined processing while continuing a database processing. Firstly, the database to be operated is switched from the main database to a duplicate database. The predetermined processing is executed to the main database which becomes the non-operation mode by the switching. Next, a database access request is distributed to the duplicate database which becomes the operation mode by the switching, thereby performing the database processing. Update information indicating the content of the update processing performed to the duplicate database is output. The output update information is reflected on the main data base for which the predetermined processing has been executed. After this, the database to be operated is switched from the duplicate database to the main database.

Method and data processing system with data replication

The present invention provides a system switching function for database management systems which requires no standby resources idling during normal operation. One aspect of the invention is directed to a method for processing databases in a system which includes a plurality of storage areas each storing a database and a plurality of computers each having a database management program running thereon which manages one of the plurality of storage areas. Each storage area is associated with only the computer managing the storage area. The method comprises, when a failure has occurred in one of the plurality of computers as a failed computer, obtaining preset substitution information indicating that the storage area managed by the database management program running on the failed computer is to be managed by the database management program running on another one of the plurality of computers as a substitute computer; and, based on the substitution information, changing association of the storage area with the failed computer to the substitute computer. The storage area is to be managed by the database management program running on the substitute computer.

Method and system for high-availability database

A database system is provided for reading data from a database to a database buffer and performing a physical sequential scan for the data on the buffer. If the preceding request for physical sequential scan is under execution, the database system operates to keep the succeeding request for scan in a waiting state until the preceding requested scan is completed and then execute the succeeding request for scan after the preceding requested scan is completed. If there are more than one succeeding requests for physical sequential scan, they are executed at the same time. Another scanning method is also provided. If the preceding request for scan is under execution, the succeeding requested scan is executed for the data existing after the halfway location at which the preceding scan process now reads the data. The short data is read from its head for completing the subsequent scan.

Method for concurrently performing a physical sequential scan of a

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Zushi, Japan

Mitsuo Miyazaki