performance improvement

hi all,

     i want to improve the performance of my program, for the following code system takes much time,

could any one help me how to avoid this .

LOOP AT log_data.

    LOOP AT it_viqmel WHERE bequi EQ log_data-equnr.

      MOVE it_viqmel-qmnum TO log_data-qmnum.

      MODIFY log_data.

    ENDLOOP.

  ENDLOOP.