An information processing device includes a statistical value holding unit configured to hold a statistical value of data included in each of two or more blocks into which a data set is divided; a query history holding unit configured to hold information about a past query on the data set as a query history; an estimation unit configured to, based on the query history, estimate a block size that minimizes an average cost of deriving an answer to a query by using the statistical value of at least one of the blocks; and a block creation unit configured to, based on the block size estimated by the estimation unit, create two or more blocks by dividing the data set, calculate the statistical value for each of the created blocks and cause the statistical value holding unit to hold the calculated statistical values.