code: public void logInited(long startTime, int totalMaps, int totalReduces) {
      if (disableHistory) {
        return;
      }
  
      if (null != writers) {
        log(writers, RecordTypes.Job,
            new Keys[] {Keys.JOBID, Keys.LAUNCH_TIME, Keys.TOTAL_MAPS,
                        Keys.TOTAL_REDUCES, Keys.JOB_STATUS},
            new String[] {jobId.toString(), String.valueOf(startTime),
                          String.valueOf(totalMaps),
                          String.valueOf(totalReduces),
                          Values.PREP.name()});
      }
    }
docs: Logs launch time of job.
  
  @param startTime start time of job.
  @param totalMaps total maps assigned by jobtracker.
  @param totalReduces total reduces.