docs: @Override
      public long getCumulativeJobInstancesCount()
      {
          DbConn em2 = Helpers.getNewDbSession();
          try
          {
              return em2.runSelectSingle("history_select_count_for_poller", Long.class, this.queue.getId(), this.engine.getNode().getId());
          }
          finally
          {
              Helpers.closeQuietly(em2);
          }
      }