A system includes a control device including a processor. The processor is configured to record a log into a log file, the log regarding information on an event having occurred in the system such that an operation state of the system at a point in time of the occurrence of the event is allowed to be specified as any of a plurality of operation states and an operation state different from the plurality of operation states. Here, the plurality of operation states correspond to a plurality of pieces of sequence processing previously defined. The processor is configured to extract the log from the log file, based on information designating a particular operation state as the operation state of the system, in units of operation states of the system such that the log includes information on an event having occurred in the particular operation state.