Help in Optimizing code

Question

Hello experts, I have a function module that runs so slow, I just want to seek some advice to help me have a better performance speed what can I used and alternatives to make my codes faster... any advice can help
Heres my <b> code </b>
<b>Declaration</b>
FUNCTION-POOL YXBW_0PRODORDER_ATTR.         "MESSAGE-ID ..
TYPE-POOLS: RSAP, RSSG, SRSC, SRSD, RSAOT, RSFH.
DATA: ippord_bw LIKE ppord_bw.
DATA : itabix LIKE sy-tabix.
DATA : V_OBJNR LIKE JEST-OBJNR.
DATA : BEGIN OF i_data_temp OCCURS 0.
        INCLUDE STRUCTURE ppord_bw.
DATA : END OF i_data_temp.
data:  begin of i_jest_obj occurs 0,
objnr like jest-objnr,
end of i_jest_obj.
*TYPES Declaration             *
TYPES : BEGIN OF t_afpo,
         aufnr LIKE afpo-aufnr, "Order Number
         plnum LIKE afpo-plnum, "Planned order number
         psamg LIKE afpo-psamg, "Scrap quantity in item
         psmng LIKE afpo-psmng, "Order item quantity
         wemng LIKE afpo-wemng, "Quantity of goods for the order item
         amein LIKE afpo-amein, "Unit of measure for in-house production
         meins LIKE afpo-meins, "Base unit of measure
         pamng LIKE afpo-pamng, "Fixed quantity of scrap from production
         pgmng LIKE afpo-pgmng, "Total planned order quantity
         ablad LIKE afpo-ablad, "Unloading point
        END OF t_afpo.
TYPES:  BEGIN OF t_afko,
         aufnr LIKE afko-aufnr, "Order Number
         gltrp LIKE afko-gltrp, "Basic finish date
         gstrp LIKE afko-gstrp, "Basic start date
         ftrms LIKE afko-ftrms, "Scheduled release date
         gltrs LIKE afko-gltrs, "Scheduled finish
         gstrs LIKE afko-gstrs, "Scheduled start
         gstri LIKE afko-gstri, "Actual start date
         gltri LIKE afko-gltri, "Actual finish date
         ftrmi LIKE afko-ftrmi, "Actual release date
         gmein LIKE afko-gmein, "Base unit of measure
         plnty LIKE afko-plnty, "Task list type
         plnnr LIKE afko-plnnr, "Key for task groupKey
         plnal LIKE afko-plnal, "Group counter
         aufld LIKE afko-aufld, "Date of BOM routing transfer
         aufpl  LIKE afko-aufpl,"Routing number for operations
         igmng LIKE afko-igmng, "Yield confirmed order confirmation
         iasmg LIKE afko-iasmg, "Scrap confirmed for order
        END OF t_afko.
TYPES:  BEGIN OF t_afvc,
         aufpl LIKE afvc-aufpl, "Routing number for operations order
         arbid LIKE afvc-arbid, "Object ID of the resource
        END OF t_afvc.
TYPES:  BEGIN OF t_zbw_afvv_c,
         aufpl LIKE zbw_afvv_c-aufpl, "Routing number
         ism03 LIKE zbw_afvv_c-ism03, "Previously confirmed activity
         ile03 LIKE zbw_afvv_c-ile03, "Unit of measure
         vgw02 LIKE zbw_afvv_c-vgw02, "Standard value
         vge02 LIKE zbw_afvv_c-vge02, "Unit of measure standard value
         isdd  LIKE zbw_afvv_c-isdd,  "Actual start: Execution (date)
         isdz  LIKE zbw_afvv_c-isdz,  "Actual start: Execution (time)
        END OF t_zbw_afvv_c.
TYPES: BEGIN OF t_CRHD,
         objid LIKE crhd-objid, "Object ID of the resource
         arbpl LIKE crhd-arbpl, "Work Center
       END OF t_CRHD.
TYPES: BEGIN OF t_jest,
         objnr LIKE jest-objnr, "Object Number
         stat  LIKE jest-stat,  "Status
       END OF t_jest.
*Internal Table Declaration    *
DATA: i_afpo    TYPE STANDARD TABLE OF t_afpo,
      wa_afpo   TYPE t_afpo,
      i_afko    TYPE STANDARD TABLE OF t_afko,
      wa_afko   TYPE t_afko,
      i_afvc    TYPE STANDARD TABLE OF t_afvc,
      wa_afvc   TYPE t_afvc,
      i_afvc_d  TYPE STANDARD TABLE OF t_afvc,
      wa_afvc_d TYPE t_afvc,
      i_jest    TYPE STANDARD TABLE OF t_jest,
      wa_jest   TYPE t_jest,
      i_zbw_afvv_c    TYPE STANDARD TABLE OF t_zbw_afvv_c,
      wa_zbw_afvv_c   TYPE t_zbw_afvv_c,
      i_CRHD    TYPE STANDARD TABLE OF t_CRHD,
      wa_CRHD   TYPE t_CRHD.
<b>Actual Code</b>
  i_data_temp[] = i_t_data[].
  IF i_data_temp[] IS INITIAL.
    RAISE rsap_customer_exit_error.
    EXIT.
  ELSE.
retrieves values of appended fields from afpo table
    SELECT aufnr     "Order Number
           plnum     "Planned order number
           psamg     "Scrap quantity in item
           psmng     "Order item quantity
           wemng     "Quantity of goods for the order item
           amein     "Unit of measure for in-house production
           meins     "Base unit of measure
           pamng     "Fixed quantity of scrap from production
           pgmng     "Total planned order quantity
           ablad     "Unloading point
      FROM afpo
      INTO TABLE i_afpo
       FOR ALL ENTRIES IN i_data_temp
     WHERE aufnr = i_data_temp-aufnr.
    IF sy-subrc = 0.
    ENDIF.
retrieves values of appended fields and aufpl from afko table that
will be used as a look up in table afvv
    SELECT aufnr     "Order Number
           gltrp     "Basic finish date
           gstrp     "Basic start date
           ftrms     "Scheduled release date
           gltrs     "Scheduled finish
           gstrs     "Scheduled start
           gstri     "Actual start date
           gltri     "Actual finish date
           ftrmi     "Actual release date
           gmein     "Base unit of measure
           plnty     "Task list type
           plnnr     "Key for task groupKey
           plnal     "Group counter
           aufld     "Date of BOM routing transfer
           aufpl     "Routing number for operations
           igmng     "Yield confirmed order confirmation
           iasmg     "Scrap confirmed for order
      FROM afko
      INTO TABLE i_afko
       FOR ALL ENTRIES IN i_afpo
     WHERE aufnr = i_afpo-aufnr.
    IF sy-subrc = 0.
    ENDIF.
loop at i_data_temp.
  CONCATENATE 'OR' i_data_temp-aufnr into i_jest_obj-objnr.
  append i_jest_obj.
endloop.
retrieves appended fields from afvv table
    SELECT aufpl      "Routing number
           ism03      "Previously confirmed activity
           ile03      "Unit of measure
           vgw02      "Standard value
           vge02      "Unit of measure standard value
           isdd       "Actual start: Execution (date)
           isdz       "Actual start: Execution (time)
      FROM zbw_afvv_c
      INTO TABLE i_zbw_afvv_c
       FOR ALL ENTRIES IN i_afko
     WHERE aufpl = i_afko-aufpl.
    IF sy-subrc = 0.
    ENDIF.
retrieves ARBID from afvc table that will be used as a lookup in CHRD
table to get the workcenter
    SELECT aufpl       "Routing number for operations order
           arbid       "Object ID of the resource
      FROM afvc
      INTO TABLE i_afvc
       FOR ALL ENTRIES IN i_afko
     WHERE aufpl = i_afko-aufpl.
    IF sy-subrc = 0.
    ENDIF.
retrieves Work Center based on the arbid selected from afvc table
    SELECT objid      "Object ID of the resource
           arbpl      " Work Center
      FROM crhd
      INTO TABLE i_crhd
       FOR ALL ENTRIES IN i_afvc
     WHERE objid = i_afvc-arbid.
    IF sy-subrc = 0.
    ENDIF.
    SELECT objnr     "Object Number
           stat      "Status
      FROM jest
      INTO TABLE i_jest
      for all entries in i_jest_obj
   where objnr = i_jest_obj-objnr
    AND   ( stat EQ 'I0045' OR stat EQ 'I0076' OR stat EQ 'I0012' ).
    IF SY-SUBRC = 0.
    ENDIF.
  ENDIF.
MAIN PROCESSING  *****
  i_afvc_d[] = i_afvc[].
  SORT i_afvc   BY aufpl ASCENDING.
  SORT i_afvc_d BY aufpl DESCENDING.
  SORT : i_afko BY aufnr,
         i_afpo BY aufnr,
         i_zbw_afvv_c BY aufpl.
  LOOP AT i_t_data INTO ippord_bw.
    itabix = sy-tabix.
clears work area
    CLEAR: wa_afpo,
           wa_afko,
           wa_afvc,
           wa_zbw_afvv_c,
           wa_crhd.
read internal table i_afpo
    READ TABLE i_afpo INTO wa_afpo
                      WITH KEY aufnr = ippord_bw-aufnr.
    IF sy-subrc = 0.
      ippord_bw-zzwemng = wa_afpo-wemng.
      ippord_bw-zzamein = wa_afpo-amein.
      ippord_bw-amein   = wa_afpo-amein.
      ippord_bw-zzpsamg = wa_afpo-psamg.
      ippord_bw-zzpgmng = wa_afpo-pgmng.
      ippord_bw-zzpamng = wa_afpo-pamng.
      ippord_bw-zzpsmng = wa_afpo-psmng.
      ippord_bw-psmng   = wa_afpo-psmng.
      ippord_bw-zzmeins = wa_afpo-meins.
      ippord_bw-zzplnum = wa_afpo-plnum.
      ippord_bw-zzablad = wa_afpo-ablad.
    ENDIF.
read internal table i_afko
    READ TABLE i_afko INTO wa_afko
                      WITH KEY aufnr = ippord_bw-aufnr.
    IF sy-subrc = 0.
      ippord_bw-zzftrms = wa_afko-ftrms.
      ippord_bw-zzgstri = wa_afko-gstri.
      ippord_bw-zzftrmi = wa_afko-ftrmi.
      ippord_bw-zzgstrp = wa_afko-gstrp.
      ippord_bw-zziasmg = wa_afko-iasmg.
      ippord_bw-zzigmng = wa_afko-igmng.
      ippord_bw-zzgmein = wa_afko-gmein.
      ippord_bw-zzplnnr = wa_afko-plnnr.
      ippord_bw-zzplnty = wa_afko-plnty.
      ippord_bw-zzplnal = wa_afko-plnal.
      ippord_bw-zzaufld = wa_afko-aufld.
      ippord_bw-zzgltrs = wa_afko-gltrs.
      ippord_bw-zzgstrs = wa_afko-gstrs.
      ippord_bw-zzgltri = wa_afko-gltri.
      ippord_bw-zzgltrp = wa_afko-gltrp.
read internal table i_afvv
      READ TABLE i_zbw_afvv_c INTO wa_zbw_afvv_c
                        WITH KEY aufpl = wa_afko-aufpl.
      IF sy-subrc = 0.
          ippord_bw-ism03 = wa_zbw_afvv_c-ism03.
          ippord_bw-ile03 = wa_zbw_afvv_c-ile03.
          ippord_bw-vgw02 = wa_zbw_afvv_c-vgw02.
          ippord_bw-vge02 = wa_zbw_afvv_c-vge02.
          ippord_bw-isdd  = wa_zbw_afvv_c-isdd.
          ippord_bw-isdz  = wa_zbw_afvv_c-isdz.
      ENDIF.
*Pull first resource
      READ TABLE i_afvc INTO wa_afvc
                        WITH KEY wa_zbw_afvv_c-aufpl.
      IF sy-subrc = 0.
        READ TABLE i_crhd INTO wa_crhd
                          WITH KEY objid = wa_afvc-arbid.
        IF sy-subrc = 0.
          ippord_bw-zzarbpl1 = wa_crhd-arbpl.
        ENDIF. "read i_crhd
      ENDIF. "read i_afvc
*Pull last resource
      CLEAR: wa_afvc_d,
             wa_crhd.
      READ TABLE i_afvc_d INTO wa_afvc_d
                        WITH KEY wa_zbw_afvv_c-aufpl.
      IF sy-subrc = 0.
        READ TABLE i_crhd INTO wa_crhd
                          WITH KEY objid = wa_afvc_d-arbid.
        IF sy-subrc = 0.
          ippord_bw-zzarbpl2 = wa_crhd-arbpl.
        ENDIF. "read i_crhd
      ENDIF.  "read i_afvc
    ENDIF. "read i_afko
    CLEAR v_objnr.
    READ TABLE i_data_temp INDEX itabix.
    SHIFT i_data_temp-aufnr LEFT BY 5 PLACES.
    CONCATENATE 'OR00000' i_data_temp-aufnr INTO v_objnr.
TECO Status
    READ TABLE i_jest INTO  wa_jest
                      WITH KEY objnr = v_objnr
                           stat  = 'I0045'.
      IF sy-subrc = 0.
        ippord_bw-zzteco = 'X'.
      ENDIF.
Deletion Flag Status
    READ TABLE i_jest INTO  wa_jest
                      WITH KEY objnr = v_objnr
                               stat  = 'I0076'.
      IF sy-subrc = 0.
        ippord_bw-zzdlfl = 'X'.
      ENDIF.
Delivered Status
    READ TABLE i_jest INTO  wa_jest
                      WITH KEY objnr = v_objnr
                               stat  = 'I0012'.
      IF sy-subrc = 0.
        ippord_bw-zzdlv = 'X'.
      ENDIF.
    MODIFY i_t_data FROM ippord_bw INDEX itabix.
  ENDLOOP.
refreshes content of internal table
  REFRESH: i_data_temp,
           i_afko,
           i_afpo,
           i_afvc,
           i_afvc_d,
           i_jest,
           i_zbw_afvv_c.
frees up the memory space containing the internal table
  FREE:    i_data_temp,
           i_afko,
           i_afpo,
           i_afvc,
           i_afvc_d,
           i_jest,
           i_crhd.

Answer 1

Also this select could be improved:
* retrieves Work Center based on the arbid selected from afvc table
SELECT objid "Object ID of the resource
arbpl " Work Center
FROM crhd
INTO TABLE i_crhd
FOR ALL ENTRIES IN i_afvc
WHERE objid = i_afvc-arbid.
IF sy-subrc = 0.
ENDIF.
Try:
* retrieves Work Center based on the arbid selected from afvc table
SELECT objid "Object ID of the resource
arbpl " Work Center
FROM crhd
INTO TABLE i_crhd
FOR ALL ENTRIES IN i_afvc
<b>WHERE OBJTY in ('A', 'AA', 'FH', 'H')</b>
WHERE objid = i_afvc-arbid.
IF sy-subrc = 0.
ENDIF.