Mass update xml failing to update records

HI All,

i am facing an issue with below mass update xml. xml is created  to update task status as Missed and closed for  ETL  period over tasks. When  i am  running below xml if any record /task has an error  the entire xml is failing to update.it should skip error records and update other tasks but its is not working like that.

Kindly suggest the way to skip error records and update next records.

<perform_batch>
  <sequential_independent>
    <mass_update_task>
      <hierarchy_select result_name="task_update">
        <primary_table>task</primary_table>
        <attrs>
          <attr>task.task_id</attr>
        </attrs>
        <from>
          <table>task</table>
          <table>PMR_MISSED_N_CLOSED_TASK_VW</table>
        </from>
        <where>
          <join_constraint>
            <constraint>
              <left_operand>PMR_MISSED_N_CLOSED_TASK_VW.task_id</left_operand>
              <operator>eq</operator>
              <right_operand>task.task_id</right_operand>
            </constraint>
          </join_constraint>
        </where>
      </hierarchy_select>
      <task>
        <task_status>MISSED_N_CLOSED</task_status>
        <update />
      </task>
      <transaction_size>50</transaction_size>
      <synchronous>N</synchronous>
    </mass_update_task>
  </sequential_independent>
</perform_batch>

Thanks,

Durga