Dear ATC, I don’t trust you any more! :-( …e.g. when your search for problematic SELECT * statements

[joachimrees1]

If you follow me around here, you probably notice that I’m digging into ATC right now.

I recently had 2 cases, where ATC would find something, but it would ignore something quite similar, right next to that.

I turned those observations into questions in case you want to have a look:

https://answers.sap.com/questions/13029896/bug-atc-check-to-search-for-unjustified-select-fin.html

https://answers.sap.com/questions/13029094/atc-check-for-s4hana-field-length-extension-materi.html

The one for the ATC-check “Search problematic SELECT * statements” I now boiled down towards its essence in a demo-class, which I can also share.

So, here’s the thing:

I have two selects, and the are quite identical, an they are equally bad in regards to greedieness: The both select all of EKPO while only two of the fields are actually needed.

The ATC-Check “Search problematic SELECT * statements” is to find just these cases. And it does. But only for one of the two:

 

And the only difference I can spot is:

The first select is surrounded by an

LOOP AT t_ekkn INTO gs_ekkn.

and the 2nd one by:

LOOP AT t_ekkn ASSIGNING FIELD-SYMBOL(<l_ekkn>).

(First might be what I find when I go ATC-hunting, the 2nd one might be what I refactor towards).

If you want to play around with it, here’s the full pasteable code:

class ZCL_JRE_ATC_SELECT_STAR definition

  public

  create public .



PUBLIC SECTION.





  METHODS do_wild_selects.



protected section.

PRIVATE SECTION.



  DATA gs_ekpo TYPE ekpo .

  ENDCLASS.







CLASS ZCL_JRE_ATC_SELECT_STAR IMPLEMENTATION.





  METHOD do_wild_selects.





    SELECT ebeln, ebelp

      FROM ekkn

      INTO TABLE @DATA(t_ekkn)

      WHERE aedat = @sy-datlo.





    DATA: gs_ekkn LIKE LINE OF t_ekkn.



    LOOP AT t_ekkn INTO gs_ekkn.



      SELECT SINGLE *

##db_feature_mode[table_len_max1]

        FROM ekpo

        INTO @gs_ekpo

        WHERE retpo = @abap_true "'x'

        AND ebeln = @gs_ekkn-ebeln

        AND ebelp = @gs_ekkn-ebelp

        AND loekz = @abap_false.

      IF sy-subrc = 0.

        WRITE gs_ekpo-menge UNIT gs_ekpo-meins.

      ENDIF.



    ENDLOOP.





    LOOP AT t_ekkn ASSIGNING FIELD-SYMBOL(<l_ekkn>).



      SELECT SINGLE *

##db_feature_mode[table_len_max1]

        FROM ekpo

        INTO @gs_ekpo

        WHERE retpo = @abap_true

        AND ebeln = @<l_ekkn>-ebeln

        AND ebelp = @<l_ekkn>-ebelp

        AND loekz = @abap_false.

      IF sy-subrc = 0.

        WRITE gs_ekpo-menge  UNIT gs_ekpo-meins.

      ENDIF.



    ENDLOOP.



  ENDMETHOD.

ENDCLASS.

So: how to trust ATC, if it only finds some of the bugs?!

best
Joachim