how to improve the performance in nested loops with 2 tables having huge number of entries in abap?

Question

Both tables sorted by key KNO

    LOOP AT lt_header INTO lwa_header.

         LOOP AT lt_items INTO lwa_item

                 WHERE key = lwa_header-KNO

                “……….

          ENDLOOP.

     ENDLOOP.

This would take more time to execute if number of entries in the table is huge. How should i modify code to improve the performance?

Answer 1

You can use parallel cursor. It's a good technique for performance improvements in nested loops. For more information check this link.

Also field symbols are better for performance.

DATA lv_tabix TYPE sy-tabix.

SORT: lt_header BY kno,
      lt_items BY kno.

LOOP AT lt_header ASSIGNING FIELD-SYMBOL(<lfs_header>).
 READ TABLE lt_items TRANSPORTING NO FIELDS
                     WITH KEY kno = <lfs_header>-kno
                     BINARY SEARCH.
 lv_tabix = sy-tabix.
 LOOP AT lt_items FROM lv_tabix ASSIGNING FIELD-SYMBOL(<lfs_item>).
   IF <lfs_header>-kno <>  <lfs_item>-kno.
     EXIT.
  ENDIF.
  "Your logic should be here..
 ENDLOOP.
ENDLOOP.