code: public static long getMBRss(Client client) {
          assert(client != null);
          long rssMax = 0;
          try {
              ClientResponse r = client.callProcedure("@Statistics", "MEMORY", 0);
              VoltTable stats = r.getResults()[0];
              stats.resetRowPosition();
              while (stats.advanceRow()) {
                  long rss = stats.getLong("RSS") / 1024;
                  if (rss > rssMax) {
                      rssMax = rss;
                  }
              }
              return rssMax;
          }
          catch (Exception e) {
              e.printStackTrace();
              System.exit(-1);
              return 0;
          }
      }
docs: Get the resident set size, in mb, for the voltdb server on the other end of the client.
  If the client is connected to multiple servers, return the max individual rss across
  the cluster.