Patent ID: 7480750

Claim:
A database server that optimizes the sizes of buffer pools for temporarily storing data from a database, comprising: a dividing ratio setting unit setting a dividing ratio for dividing a memory area of a predetermined size into a plurality of said buffer pools used selectively according to the type of a transaction; a response time measuring unit measuring the response time that elapses between the issuance of a request for a plurality of transactions to said database server and the completion of processing of said plurality of transactions with said dividing ratio being set; a response time computation formula generating unit calculating parameters of a response time calculation formula for calculating said response time based on the size of each of said plurality of buffer pools from said set dividing ratio and said measured response time, wherein the response time calculation formula is r ⁡ ( t ) = ∑ i = 1 n ⁢ ⁢ a i ⁢ ⅇ - b i ⁢ u i ⁡ ( t ) + c ⁡ ( t ) , where r(t) represents an average response time in a time period from a time t to a time (t+1), u i (t) represents sizes of the plurality of the buffer pools set in the time period from t to time (t+1), c (t) is a noise term a i represents an influence of each buffer pool on the response time on a basis of the dividing ratio and the response time, and b i represents an influence of a size of each buffer pool on the res response time when accessing data to be stored in the buffer pool; and a dividing ratio calculation unit calculating said dividing ratio that minimizes said response time by using said response time calculation formula the parameters of which are calculated by said response time calculation formula generating unit; wherein said dividing ratio setting unit sets the dividing ratio calculated by said dividing ratio calculating unit.