Image Number 10 for United States Patent #8117167.
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.