Patent ID: 8196034

Claim:
A computer system, comprising: a storage system comprising a plurality of disk devices comprising disks, and a disk access control part for controlling access to said plurality of disk devices, said plurality of disk devices storing a database (DB); a computer comprising a DB management information storage area operable to store DB management information for managing said DB, the computer operable to execute a database management system (DBMS) for operating said DB; and a disk rotation control part operable to cause a disk of a disk device, which is not to be accessed, to rotate at a second rate of speed, which is zero or greater, and which is slower than a first rate of speed, which is the rotation speed at access time, wherein said DB comprises a plurality of DB schema, the DB schema being an element to be accessed by said DBMS; said DB management information comprises information denoting which DB schema is stored in which location; said DBMS is operable to receive a query, prepare a query plan for said received query, and, in accordance with the query plan, issue an access request to a DB schema specified from said DB management information; and said disk rotation control part, upon said DBMS receiving a query, is operable to specify, from the query plan of the query and said DB management information, the storage location of the DB schema to be accessed at the time the query is processed, cause the disk of the disk device comprising this specified storage location to rotate at said first rate of speed, when said DBMS ends said query processing, information of said ended query is sent to said disk rotation control part as an ending request, and when receiving said ending request from said DBMS, said disk rotation control part stops the disk of all disk devices that were accessed at the time the query is processed.