SAP ABAP程序性能优化 2

以下是以前看到的一些关于SAP ABAP程序性能优化的东西 

As you all know, it is important to use as many key fields as possible in WHERE clauses of SELECT statements. Sometimes you are not sure about the value of some key fields. They seem to be empty (Initial value) but you are afraid to use this in your ABAP coding.

Using the option GE (greater equal) in your coding can improve your performance considerably without the risk of table lines not being selected.

About WHERE Code:

REPORT ZZBM_SELECT_1 .
TABLES: S001.
CONSTANTS: SSOUR_INI  LIKE S001-SSOUR VALUE   IS INITIAL,
           VRSIO_INI  LIKE S001-VRSIO VALUE   IS INITIAL,
           SPMON_INI  LIKE S001-SPMON VALUE   IS INITIAL,
           SPTAG_INI  LIKE S001-SPTAG VALUE   IS INITIAL,
           SPWOC_INI  LIKE S001-SPWOC VALUE   IS INITIAL,
           SPBUP_INI  LIKE S001-SPBUP VALUE   IS INITIAL.


DATA: TA_S001 TYPE STANDARD TABLE OF S001.
DATA: WA_S001 TYPE S001.

SELECT-OPTIONS:
              SO_SPTAG   FOR S001-SPTAG OBLIGATORY,
              SO_KUNNR   FOR S001-KUNNR OBLIGATORY,
              SO_VKORG   FOR S001-VKORG OBLIGATORY,
              SO_VTWEG   FOR S001-VTWEG OBLIGATORY,
              SO_SPART   FOR S001-SPART OBLIGATORY,
              SO_MATNR   FOR S001-MATNR OBLIGATORY.

START-OF-SELECTION.

SELECT        * FROM  S001
       INTO TABLE TA_S001
       WHERE  SSOUR  GE SSOUR_INI     "Greater Equal initial value
       AND    VRSIO  GE VRSIO_INI     "   idem
       AND    SPMON  GE SPMON_INI     "   idem
       AND    SPTAG  IN SO_SPTAG
       AND    SPWOC  GE SPWOC_INI     "   idem
       AND    SPBUP  GE SPBUP_INI     "   idem
       AND    KUNNR  IN SO_KUNNR
       AND    VKORG  IN SO_VKORG
       AND    VTWEG  IN SO_VTWEG
       AND    SPART  IN SO_SPART
       AND    MATNR  IN SO_MATNR.

About DELETE code:

*--- D01K919273 Begin delete 
*--- Delete deliveries not to be processed
*  loop at th_vbuk.
*    delete th_vlpma where vbeln eq th_vbuk-vbeln.
*  endloop.                             " th_vbuk.
*--- D01K919273 End delete
*--- Begin add D01K919273
   loop at th_vlpma into th_vlpmatmp.
      read table th_vbuk with key vbeln = th_vlpmatmp-vbeln
         binary search.

      check sy-subrc ne 0.
      append th_vlpmatmp.
   endloop.    
*--- End add D01K919273