is computed by counting the number of pairing of data entries of the data sets r and s can be formulated as follows cost ue89e ue89e cpu uf603 r uf604 u00d7 uf604 ue89e s uf604 u00d7 3 u2308 1 u025b u2309 d p 2 in addition the disk i o cost cost io as the disk access cost can be formulated as follows cost io r block 3 dp s block 3 for the total number of disk blocks in which r and s are stored r block for r and s block for s according to equations 2 and 3 it is understood that as the number of partitioning dimensions d p increases the cpu cost decreases under an assumption that 1 u03b5 gt 3 while the disk i o cost increases that is there is a trade off between the cpu cost and the disk i o cost in regard to the performance of the similarity join in this aspect the method according to the present embodiment determines the number of partitioning dimensions by comparing the size of the data set with that of the disk block assuming that the average cell size is the same as the size of a disk block the total number of cells n.