A method for stream-processing data including a missing part in real time and thereafter updating the result of the stream processing. A technique for processing data is included. The technique includes receiving data; detecting a probably missing part in the received data while stream-processing the received data in real time; and comparing master data corresponding to the received data and having no missing part with the probably missing part, and if the received data has the missing part, updating the result of the stream processing using the master data.