code: @Override
    public void run() {
      long startTime = System.currentTimeMillis();
      
      try {
        LOG.info("Starting the history thread ...");
        while (!core.shutdownPending()) {
          checkRampUp(startTime);
          cleanUpHistory();
          Thread.sleep(loopSleepTime);
        }
        LOG.info("History thread shutdown.");
      } catch (Exception e) {
        LOG.error("ServerHistory died", e);
      } finally {
        core.shutdown();
      }
    }
docs: Should be called when the server starts to start recording the history
  (the namespace operations from the edit log).