Performance and Safety in Enhancements

Explanation

Enhancements often run inside critical SAP standard flows. A small piece of bad code can slow down sales order save, delivery processing, billing, pricing, IDoc posting or invoice creation. Developers must avoid repeated SELECT statements inside loops, broad database reads, unnecessary commits, long-running RFC calls and heavy logic in frequently called exits. Enhancements should be lightweight and should call reusable services only when necessary. Performance should be measured if the enhancement is executed for many items or in background mass processing.

Code example

* Bad idea inside enhancement:* SELECT inside item loop can slow down order save. LOOP AT xvbap ASSIGNING FIELD-SYMBOL(<ls_item>).   SELECT SINGLE mtart    FROM mara    INTO @DATA(lv_mtart)    WHERE matnr = @<ls_item>-matnr. ENDLOOP. * Better idea:* Build driver table first, select once, then use hashed lookup. DATA lt_matnr TYPE SORTED TABLE OF matnr WITH UNIQUE KEY table_line. LOOP AT xvbap ASSIGNING <ls_item>.  INSERT <ls_item>-matnr INTO TABLE lt_matnr.ENDLOOP. IF lt_matnr IS NOT INITIAL.  SELECT matnr, mtart    FROM mara    INTO TABLE @DATA(lt_mara)    FOR ALL ENTRIES IN @lt_matnr    WHERE matnr = @lt_matnr-table_line.ENDIF.

Real project scenario

A pricing enhancement selected customer data inside an item loop for every item. In large orders, save time increased from seconds to minutes. The fix was to preload required data once and use internal table lookup.

Common mistakes

- SELECT inside enhancement item loop. - Calling slow RFC synchronously during save. - Using COMMIT WORK inside standard save flow. - Not testing mass processing impact.

Best practices

- Keep enhancement logic lightweight. - Avoid repeated database access. - Do not commit unless framework allows it. - Measure performance in mass scenarios. - Use buffered/config data carefully.

Interview angle

Senior interviews often ask why enhancement code can create performance problems. Mention frequency, loops, database access and update safety.