docs: @Override
      public ResultSet getTableTypes() throws SQLException
      {
          checkClosed();
          VoltTable vtable = new VoltTable(new ColumnInfo("TABLE_TYPE", VoltType.STRING));
          for (String type : tableTypes) {
              vtable.addRow(type);
          }
          JDBC4ResultSet res = new JDBC4ResultSet(this.sysCatalog, vtable);
          return res;
      }