code: @Override
      protected int queueSize(Connection conn) {
          Map<String, Object> row = getJdbcHelper().executeSelectOne(conn, SQL_COUNT);
          Integer result = DPathUtils.getValue(row, FIELD_COUNT, Integer.class);
          return result != null ? result.intValue() : 0;
      }
docs: {@inheritDoc}
  
  @since 0.6.0