1. A data processing method executed in a system where first data processing is performed using a plurality of nodes in parallel and second data processing is performed on a result of the first data processing, the data processing method comprising: splitting, by a processor, data into a first segment and a plurality of second segments with reference to a memory storing results of the first data processing previously performed, the first segment being a segment for which the results stored in the memory are usable, the plurality of second segments being segments for which the results stored in the memory are not usable; assigning, by the processor, the plurality of second segments to the plurality of nodes, and using the plurality of nodes in parallel to perform the first data processing on the plurality of second segments; and performing, by the processor, the second data processing on a previous result corresponding to the first segment, which is stored in the memory, and results obtained from the plurality of second segments using the plurality of nodes.