Patent ID: 7092971

Claim:
A management computer that is connected to a plurality of storage devices that store data of a data base and a data base host computer having a Database Management System (DBMS) that accesses to the data within the data base via said management computer, the management computer comprising: a first interface section that is connected to the data base host computer; a second interface section that is connected to the storage devices; a first control device which is configured to receive a plurality of access requests sent from said database host computer to access a plurality of virtual volumes and relay said access requests to said storage devices to access a plurality of storage areas in a plurality of disks of said storage devices based on a relationship between said virtual volumes and said storage areas, said virtual volumes as used by said database host computer are transparent as to their relationship to one or more of said storage areas; and a first cache memory, wherein the first interface section receives from the data base host computer a plurality of execution plans for data base management processings to be executed by the data base host computer, wherein the first control device stores priority information indicating a level of priority for said execution plans relative to each other and an execution sequence of accesses to said virtual volumes with respect to each of said execution plans, and preliminarily estimates a first virtual volume of said virtual volumes that stores the data to be accessed by the data base host computer based on the execution plans, wherein the first control device converts first information of the first virtual volume into second information that is used to indicate a first storage area of said storage areas, wherein the second interface section transmits a first read request including the second information to the storage devices, wherein said first read request requests to read data stored in the first storage area into a second cache memory of at least one storage device having the first storage area, wherein a second control device of the at least one storage device processes the first read request by reading the stored data stored in the first storage area into the second cache memory, wherein the second interface section further transmits a second read request to read data read out of the second cache memory, wherein the second interface section receives data read out of the second cache memory in response to the second read request, and stores the data in said first cache memory, and wherein the first interface section transmits the data stored in said first cache memory to the data base host computer when the first interface section receives an access request including the first information from the data base host computer.