Abstract: A memory use amount used by each object can be calculated for each of a plurality of pieces of generator property information that is information related to generation of data such as user information and request information. A computer for executing a program to generate data executes a step of specifying, from a storage device in which the plurality of pieces of generator property information on the data and identification information that the data has are associated and held, data corresponding to each piece of the generator property information and calculating a memory use amount of the specified data, and a step of outputting the calculated memory use amount to an interface. Further, a data structure of the data has a control area for storing information on control of the data and a data area, and the computer inserts the identification information into the data area.