Time out error 1.6 million internal table fields are computed using FMs

Question

Hi , All ...
The Report running fine in server with less 300 record but ...production server which has 1.6 million record it  gives error as time-out error and takes hell amount of time.
Please suggest ugently ..
I have tried few things
Internal table having 1.6 lacs ... fields to compute .. i have token in a batch
loop at i_cinfo into s_cinfo from 1 to  100000.
and so on ...also applied all the performace related .. like indexs, work areas , deleting adjacent duplicates , for all entries ..wherever applicable.
Please Suggest .
Report is as below
REPORT  ZUSOTCBD_CREDIT_REPORT .
TABLES : KNA1,    " General Data Customer Master
         KNB1,    " Customer Master (Company Code)
         KNC1,    " Customer master (transaction figures)
         KNKK,    " Customer master credit management: Control area data
         T009,    " Fiscal Year Variants P
         T009Y,   " Shortened fiscal years in Asset Accounting P
         T001,    " Co. Codes
         T001CM,  " Permitted Credit Control Areas per Company Code
         RF42B,   " Structure to hold credit data.
         RF035,   " Structure to hold credit managment fields
         RF02L,   " Structure to hold credit data.
         TRAS,    " Interval for Days in Arrears P
         T000CM.  " Data for DSO calculation.
Types
TYPES:
  BEGIN OF type_final,
    string(50) TYPE c,                            " String Value for Title
  END OF type_final.
data:wa_final     TYPE type_final.                " Work Area to hold Title Data
DATA:    RASID    TYPE RF035-RASID value 'R03N'. " For Days in interval
DATA:    MONAT(2) TYPE N.
DATA:    GJAHR    TYPE  KNC1-GJAHR.
DATA:    LD_PERIODS(32) TYPE N
                       VALUE '01020304050607080910111213141516'.
DATA     sytabix type sy-tabix.
DATA     LAND      TYPE KNA1-LAND1 VALUE 'US'.   " Country Key
DATA:   LD_PERIOD    TYPE BSID-MONAT,            " Fiscal Year Variant
        LD_GJAHR   TYPE KNC1-GJAHR,
        LD_COUNTER TYPE SY-TABIX.
Internal Tables
Internal table to hold Title Data                                   *
DATA:
  i_final    TYPE STANDARD TABLE OF type_final.
**Internal Table Permitted Credit Control Areas per Company Code
DATA:    BEGIN OF TCMTAB OCCURS 10.
        INCLUDE STRUCTURE T001CM.
DATA:    END   OF TCMTAB.
*Internal table to store Customer no.
DATA :  BEGIN OF ICUST OCCURS 0,
           KUNNR             TYPE KNA1-KUNNR,    " Customer No.
        END   OF ICUST.
DATA:    BEGIN OF BUKTAB OCCURS 20,
           KKBER             LIKE T001-KKBER,    " Credit Control Area
           BUKRS             LIKE T001-BUKRS,    " Co. Code
           WAERS             LIKE T001-WAERS,    " Currency
           PERIV             LIKE T001-PERIV,    " Fiscal Year Variant
           BUTXT             LIKE T001-BUTXT,
         END   OF BUKTAB.
Internal Table to store Fiscal year Data .
DATA:    BEGIN OF GJATAB OCCURS 5,
           PERIV             LIKE T001-PERIV,    " Fiscal Year Variant
           GJAHR             LIKE KNC1-GJAHR,    " Fiscal Year
           MONAT             LIKE T009-ANZBP,    "
           ANZBP             LIKE T009-ANZBP,    " Number of posting periods
         END   OF GJATAB.
*Main Output internal table to be used to store credit history Information
DATA : BEGIN OF I_CINFO occurs 0,
             KUNNR TYPE   KNB1-KUNNR,     " Customer
             KNKLI TYPE   KNKK-KNKLI,     " Customer's account number with credit limit reference
             KKBER TYPE   KNKK-KKBER,     " Credit Control Area
             CTLPC TYPE   KNKK-CTLPC,     " Risk Category
             KLIMK TYPE   KNKK-KLIMK,     " Credit Limit
             SBGRP TYPE   KNKK-SBGRP,     " Credit representative group for credit management
             ERDAT TYPE   KNKK-ERDAT,     " Created On
             DTREV TYPE   KNKK-DTREV,     " Last Internal Review
             REVDB TYPE   KNKK-REVDB,     " Last External Review
             SALDO TYPE   RF42B-SALDO,    " Balance
             DSOIN TYPE   RF02L-DSOIN,    " DSO
             H06SA TYPE   RF035-H06SA,    " Highest Balance at the end of 6 Months
             H06JA TYPE   RF035-H06JA,    " Year highest Balance 6 Months
             H06MO TYPE   RF035-H06MO,    " Month OF hihest Balance 6 Months
             H12SA TYPE   RF035-H12SA,    " Highest Balance at the end of 12 Months
             H12JA TYPE   RF035-H12JA,    " Year highest Balance 12 Months
             H12MO TYPE   RF035-H12MO,    " Month OF hihest Balance 12 Months
             UMP2U TYPE   RF42B-UMP2U,    " Sales from the current Year
             UMP1U TYPE   RF42B-UMP1U,    " Sales from the Previous Year
             SFAEL TYPE   RF035-SFAEL,    " Total Past Due Open Item
             SFAE1 TYPE   RF035-SFAE1,    " Aging buckets 0-15
             SFAE2 TYPE   RF035-SFAE2,    " Aging buckets 16-30
             SFAE3 TYPE   RF035-SFAE3,    " Aging buckets 31-60
             SFAE4 TYPE   RF035-SFAE4,    " Aging buckets 60-90
             SFAE5 TYPE   RF035-SFAE5,    " Aging buckets Over 90
      END Of I_CINFO.
DATA : BEGIN OF S_CINFO ,
             KUNNR TYPE   KNB1-KUNNR,     " Customer
             KNKLI TYPE   KNKK-KNKLI,     " Customer's account number with credit limit reference
             KKBER TYPE   KNKK-KKBER,     " Credit Control Area
             CTLPC TYPE   KNKK-CTLPC,     " Risk Category
             KLIMK TYPE   KNKK-KLIMK,     " Credit Limit
             SBGRP TYPE   KNKK-SBGRP,     " Credit representative group for credit management
             ERDAT TYPE   KNKK-ERDAT,     " Created On
             DTREV TYPE   KNKK-DTREV,     " Last Internal Review
             REVDB TYPE   KNKK-REVDB,     " Last External Review
             SALDO TYPE   RF42B-SALDO,    " Balance
             DSOIN TYPE   RF02L-DSOIN,    " DSO
             H06SA TYPE   RF035-H06SA,    " Highest Balance at the end of 6 Months
             H06JA TYPE   RF035-H06JA,    " Year highest Balance 6 Months
             H06MO TYPE   RF035-H06MO,    " Month OF hihest Balance 6 Months
             H12SA TYPE   RF035-H12SA,    " Highest Balance at the end of 12 Months
             H12JA TYPE   RF035-H12JA,    " Year highest Balance 12 Months
             H12MO TYPE   RF035-H12MO,    " Month OF hihest Balance 12 Months
             UMP2U TYPE   RF42B-UMP2U,    " Sales from the current Year
             UMP1U TYPE   RF42B-UMP1U,    " Sales from the Previous Year
             SFAEL TYPE   RF035-SFAEL,    " Total Past Due Open Item
             SFAE1 TYPE   RF035-SFAE1,    " Aging buckets 0-15
             SFAE2 TYPE   RF035-SFAE2,    " Aging buckets 16-30
             SFAE3 TYPE   RF035-SFAE3,    " Aging buckets 31-60
             SFAE4 TYPE   RF035-SFAE4,    " Aging buckets 60-90
             SFAE5 TYPE   RF035-SFAE5,    " Aging buckets Over 90
      END Of s_cinfo.
*Internal table to hold month-wise balance.
DATA:    BEGIN OF SALTAB OCCURS 12,
           LNUMM(2)     TYPE N,             " Month
           SALDO        LIKE RF42B-SALDO,   " Balance
         END   OF SALTAB.
*Internal table used for computing the Balance fields
DATA:    BEGIN OF SALDO,
           UML01             LIKE KNC1-UM01S,
           UML02             LIKE KNC1-UM01S,
           UML03             LIKE KNC1-UM01S,
           UML04             LIKE KNC1-UM01S,
           UML05             LIKE KNC1-UM01S,
           UML06             LIKE KNC1-UM01S,
           UML07             LIKE KNC1-UM01S,
           UML08             LIKE KNC1-UM01S,
           UML09             LIKE KNC1-UM01S,
           UML10             LIKE KNC1-UM01S,
           UML11             LIKE KNC1-UM01S,
           UML12             LIKE KNC1-UM01S,
         END   OF SALDO.
Structure to hold Bal fields ------ -------
DATA:    BEGIN OF SKNKK,
           KUNNR             LIKE KNA1-KUNNR,  " Customer Number 1: Debitor
           KONTO             LIKE KNKK-KUNNR,
           SFAE1             LIKE RF035-SFAE1, " Aging buckets 0-15
           SFAE2             LIKE RF035-SFAE2, " Aging buckets 16-30
           SFAE3             LIKE RF035-SFAE3, " Aging buckets 30-60
           SFAE4             LIKE RF035-SFAE4, " Aging buckets 60-90
           SFAE5             LIKE RF035-SFAE5, " Aging buckets Over 90
           SFAEL             LIKE RF035-SFAEL, " Total Due of Items
           UML01             LIKE KNC1-UM01S,
           UML02             LIKE KNC1-UM01S,
           UML03             LIKE KNC1-UM01S,
           UML04             LIKE KNC1-UM01S,
           UML05             LIKE KNC1-UM01S,
           UML06             LIKE KNC1-UM01S,
           UML07             LIKE KNC1-UM01S,
           UML08             LIKE KNC1-UM01S,
           UML09             LIKE KNC1-UM01S,
           UML10             LIKE KNC1-UM01S,
           UML11             LIKE KNC1-UM01S,
           UML12             LIKE KNC1-UM01S,
           UMP1U             LIKE RF42B-UMP1U, " Sales from the Previous Year
           UMP2U             LIKE RF42B-UMP2U, " Sales from the current Year
           SALDO             LIKE RF42B-SALDO, " Balance
         END   OF SKNKK.
DATA :  BEGIN OF ICUST1 OCCURS 0,
           KUNNR             TYPE KNA1-KUNNR,    "For Customer Filter.
        END   OF ICUST1.
**Internal table to hold fiscal varriants
DATA: BEGIN OF LT_PERIODS OCCURS 12,
         PERIOD LIKE BSID-MONAT,
         GJAHR  LIKE KNC1-GJAHR,
       END OF LT_PERIODS.
**Constants
constants :  BUKRS1 TYPE KNB1-BUKRS VALUE '1000',
             BUKRS2 TYPE KNB1-BUKRS VALUE '1031',
             Recs   Type i value '200',
             B_count type i value '2'.
      INITIALIZATION
INITIALIZATION.
  IF RASID IS INITIAL.
    SELECT * FROM TRAS.
      EXIT.
    ENDSELECT.
    IF SY-SUBRC = 0.
      RASID = TRAS-RASID.
    ENDIF.
  ENDIF.
SELECTION-SCREEN
  parameters : p_path type rlgrap-filename default 'C:\Documents and Settings\C890971\Desktop\Credit_history.XLS'.
Start of selection processing
START-OF-SELECTION.
**Get Customers for Co. Code 1000 & 1031.
  PERFORM GET_CUST.
Get  / Compute Credit Information data for Company Codes 1000 & 1031.
  PERFORM GET_CREDIT_DATA.
End of selection processing
*END-OF-SELECTION.
Listing Credit History Data
  PERFORM DOWNLOAD_CREDIT_DATA.
S U B R O U T I N E S
*&      Form  GET_CUST
      text
-->  p1        text
<--  p2        text
FORM GET_CUST .
Get US only Customers.
  Refresh icust.
  Select kunnr from kna1 appending table icust
                               where Land1 = land.
**Delete duplicate records
  Delete Adjacent duplicates from icust comparing kunnr.
  if icust[] is not initial.
   Limit the selection some more to Co. Code 1000 & 1031
  As join will cost overhead as compared.
  Select kunnr from knb1 into table icust1
                              for all entries in icust
                              where kunnr = icust-kunnr
                              and   bukrs = bukrs1
                              OR    bukrs = bukrs2.
**Delete duplicate records
  Delete Adjacent duplicates from icust1 comparing kunnr.
   endif.
**Free memory.
  Free icust.
Credit Control Area
  select * from T001CM into table TCMTAB
                       where bukrs = bukrs1 OR
                             bukrs = bukrs2.
ENDFORM.                    " GET_CUST
*&      Form  GET_CREDIT_DATA
      text
-->  p1        text
<--  p2        text
FORM GET_CREDIT_DATA .
  DATA : L_TEXT(60) TYPE C ,
         Ltext1(50) type C value 'Computing Credit-History Data For',
         Ltext2(10) type C value 'Customers',
         L_PCT type i value '10',
         L_recs type i,
         l_batch_recs type i,
         l_s_rec type i value 1,
         l_recs1(7) type N.
***Fetch data from KNKK table
  PERFORM GET_KNKK_DATA  .
***Computing Crredit Fields
**Number of Customers For whom Deatils needed.
  Describe table I_CINFO lines l_recs.
  l_recs1 = l_recs.
  Concatenate Ltext1 l_recs1 Ltext2 into l_text separated by ' '.
  PERFORM GET_PGRESS_INDICATOR USING l_text l_pct.
***If records are more than 200000, should be processed  batch-wise
  If l_recs > recs.
    l_batch_recs = abs( l_recs / b_count ).
    Do b_count times.
      loop at i_cinfo INTO S_CINFO from l_S_REC to l_batch_recs.
**Remember the row
        sytabix = sy-tabix.
**Compute DSO
        PERFORM GET_DSO_FIELD .
Compute rest credit history data.
        PERFORM COMPUTE_SFIELDS.
      endloop.
      l_S_REC = l_S_REC + l_batch_recs.
      l_batch_recs = l_batch_recs + l_batch_recs.
      IF l_batch_recs ge l_recs.
        l_batch_recs = l_recs.
      eNDIF.
Commit up to here to release the DB locks.
      Commit work.
    enddo.
  else.
    loop at i_cinfo INTO S_CINFO.
**Remember the row
      sytabix = sy-tabix.
**Compute DSO
      PERFORM GET_DSO_FIELD .
Compute rest credit history data.
      PERFORM COMPUTE_SFIELDS.
    endloop.
  Endif.
ENDFORM.                    " GET_CREDIT_DATA
*&      Form  GET_KNKK_DATA
      text
     -->P_ICUST_KUNNR  text
FORM GET_KNKK_DATA .
  if icust1[] is not initial.
  SELECT   KUNNR KNKLI KKBER  CTLPC KLIMK
           SBGRP ERDAT DTREV REVDB
           from KNKK into corresponding fields of table I_Cinfo
           for all entries in icust1
           where kunnr = icust1-kunnr.
  Delete Adjacent duplicates from i_cinfo comparing kunnr.
  endif.
**Free Memory for internal table icust1.
  Free icust1.
ENDFORM.                    " GET_KNKK_DATA
**&      Form  GET_DSO_FIELD
      text
-->  p1        text
<--  p2        text
FORM GET_DSO_FIELD .
***Determine DSO Parameter
  PERFORM DSO_PARAMETER.
***Compute DSO
  CALL FUNCTION 'CUSTOMER_DSO_CALCULATION'
    EXPORTING
      I_KKBER       = s_cinfo-kkber
      I_KUNNR       = s_cinfo-kunnr
      I_ANZBUPER    = T000CM-DSOPP
      I_XCHILDS     = T000CM-DSOCH
      I_ACTBALANCE  = T000CM-DSOAB
    IMPORTING
      E_DSOIN       = RF02L-DSOIN
    EXCEPTIONS
      ERROR_MESSAGE = 1.
ENDFORM.                    " GET_DSO_FIELD
*&      Form  DSO_PARAMETER
      text
-->  p1        text
<--  p2        text
FORM DSO_PARAMETER.
  IF T000CM-DSOPP IS INITIAL.
    SELECT SINGLE * FROM T000CM.
    IF SY-SUBRC     EQ 0.
      IF T000CM-DSOPP IS INITIAL.
        T000CM-DSOPP = '003'.
      ENDIF.
    ELSE.
      T000CM-DSOPP = '003'.
      T000CM-DSOCH = ' '.
      T000CM-DSOAB = 'X'.
    ENDIF.
  ENDIF.
ENDFORM.                    " DSO_PARAMETER
-->  p1        text
<--  p2        text
FORM PERIODE_ERMITTELN_EXC USING
            P03_BUDAT    LIKE SYST-DATUM
            P03_GJAHR    LIKE KNC1-GJAHR
            P03_MONAT    LIKE MONAT.
  CALL FUNCTION 'FI_PERIOD_DETERMINE'
       EXPORTING
            I_BUDAT = P03_BUDAT
            I_PERIV = T001-PERIV
          I_BUKRS = T001-BUKRS
            I_GJAHR = P03_GJAHR
            I_MONAT = P03_MONAT
       IMPORTING
            E_GJAHR = P03_GJAHR
            E_MONAT = P03_MONAT
       EXCEPTIONS
            ERROR_MESSAGE = 1.
ENDFORM.                    "PERIODE_ERMITTELN_EXC
*&      Form  COMPUTE_SFIELDS
      text
-->  p1        text
<--  p2        text
FORM COMPUTE_SFIELDS .
**Compute Balance
  PERFORM GET_SFIELDS .
  S_CINFO-DSOIN = RF02L-DSOIN.
  S_CINFO-SALDO = RF035-SALDO.
  S_CINFO-H06SA = RF035-H06SA.
  S_CINFO-H06JA = RF035-H06JA.
  S_CINFO-H06MO = RF035-H06MO.
  S_CINFO-H12SA = RF035-H12SA.
  S_CINFO-H12JA = RF035-H12JA.
  S_CINFO-H12MO = RF035-H12MO.
  S_CINFO-UMP2U = RF42B-UMP2U.
  S_CINFO-UMP1U = RF42B-UMP1U.
  S_CINFO-SFAEL = RF035-SFAEL.
  S_CINFO-SFAE1 = RF035-SFAE1.
  S_CINFO-SFAE2 = RF035-SFAE2.
  S_CINFO-SFAE3 = RF035-SFAE3.
  S_CINFO-SFAE4 = RF035-SFAE4.
  S_CINFO-SFAE5 = RF035-SFAE5.
modify..
  MODIFY I_CINFO FROM S_CINFO INDEX sytabix.
  CLEAR: S_CINFO,RF035,RF02L, RF42B.
ENDFORM.                    " COMPUTE_SFIELDS
      text
     -->P_C_INFO_KUNNR  text
FORM GET_CUST_BAL_INFO.
  LOOP AT TCMTAB.
    CALL FUNCTION 'FI_COMPANY_CODE_DATA'
      EXPORTING
        I_BUKRS       = TCMTAB-BUKRS
      IMPORTING
        E_T001        = T001
      EXCEPTIONS
        ERROR_MESSAGE = 1.
    IF SY-SUBRC = 0.
      MOVE-CORRESPONDING T001 TO BUKTAB.
      BUKTAB-KKBER = TCMTAB-KKBER.
      COLLECT BUKTAB.
    ENDIF.
  ENDLOOP.
  LOOP AT BUKTAB WHERE PERIV NE SPACE.
    GJATAB-PERIV = BUKTAB-PERIV.
    COLLECT GJATAB.
  ENDLOOP.
  CLEAR: MONAT.
  LOOP AT GJATAB.
    T001-PERIV = GJATAB-PERIV.
    CLEAR: GJAHR, MONAT.
    PERFORM PERIODE_ERMITTELN_EXC USING SY-DATLO GJAHR MONAT.
    CHECK SY-SUBRC = 0.
    GJATAB-GJAHR = GJAHR.
    GJATAB-MONAT = MONAT.
    SELECT SINGLE * FROM T009 WHERE PERIV = GJATAB-PERIV.
    IF SY-SUBRC = 0.
      GJATAB-ANZBP = T009-ANZBP.
    ENDIF.
    MODIFY GJATAB.
  ENDLOOP.
  LOOP AT BUKTAB.
    CHECK NOT ( BUKTAB-PERIV IS INITIAL ).
    READ TABLE GJATAB WITH KEY BUKTAB-PERIV.
    CHECK SY-SUBRC = 0
      AND NOT ( GJATAB-GJAHR IS INITIAL ).
    CALL FUNCTION 'CUSTOMER_BALANCE'
      EXPORTING
        KUNNR      = S_cinfo-kunnr
        BUKRS      = BUKTAB-BUKRS
        GJAHR      = GJATAB-GJAHR
        MONAT      = GJATAB-MONAT
        PERIV      = GJATAB-PERIV
        ANZBP      = GJATAB-ANZBP
        XH6MON     = 'X'
        XH12MON    = 'X'
      IMPORTING
        UMP2U      = RF42B-UMP2U
        VMP2U      = RF42B-UMP1U
        SALDO      = RF035-SALDO
        UML01      = SALDO-UML01
        UML02      = SALDO-UML02
        UML03      = SALDO-UML03
        UML04      = SALDO-UML04
        UML05      = SALDO-UML05
        UML06      = SALDO-UML06
        UML07      = SALDO-UML07
        UML08      = SALDO-UML08
        UML09      = SALDO-UML09
        UML10      = SALDO-UML10
        UML11      = SALDO-UML11
        UML12      = SALDO-UML12
      EXCEPTIONS
        NO_BALANCE = 4.
    IF SY-SUBRC = 0.
      SKNKK-UMP1U = SKNKK-UMP1U + RF42B-UMP1U.
      SKNKK-UMP2U = SKNKK-UMP2U + RF42B-UMP2U.
      SKNKK-SALDO = SKNKK-SALDO + RF035-SALDO.
      SKNKK-UML01 = SKNKK-UML01 + SALDO-UML01.
      SKNKK-UML02 = SKNKK-UML02 + SALDO-UML02.
      SKNKK-UML03 = SKNKK-UML03 + SALDO-UML03.
      SKNKK-UML04 = SKNKK-UML04 + SALDO-UML04.
      SKNKK-UML05 = SKNKK-UML05 + SALDO-UML05.
      SKNKK-UML06 = SKNKK-UML06 + SALDO-UML06.
      SKNKK-UML07 = SKNKK-UML07 + SALDO-UML07.
      SKNKK-UML08 = SKNKK-UML08 + SALDO-UML08.
      SKNKK-UML09 = SKNKK-UML09 + SALDO-UML09.
      SKNKK-UML10 = SKNKK-UML10 + SALDO-UML10.
      SKNKK-UML11 = SKNKK-UML11 + SALDO-UML11.
      SKNKK-UML12 = SKNKK-UML12 + SALDO-UML12.
    ENDIF.
  ENDLOOP.
ENDFORM.                    "
*&      Form  GET_SFIELDS
      text
-->  p1        text
<--  p2        text
FORM GET_SFIELDS .
  sknkk-kunnr = S_CINFO-KUNNR.
**Clear target to store computed values
  CLEAR: RF035.
**Compute Balance fields
  PERFORM GET_CUST_BAL_INFO.
  REFRESH: SALTAB.
  SALTAB-LNUMM = '01'. SALTAB-SALDO = SKNKK-UML01. APPEND SALTAB.
  SALTAB-LNUMM = '02'. SALTAB-SALDO = SKNKK-UML02. APPEND SALTAB.
  SALTAB-LNUMM = '03'. SALTAB-SALDO = SKNKK-UML03. APPEND SALTAB.
  SALTAB-LNUMM = '04'. SALTAB-SALDO = SKNKK-UML04. APPEND SALTAB.
  SALTAB-LNUMM = '05'. SALTAB-SALDO = SKNKK-UML05. APPEND SALTAB.
  SALTAB-LNUMM = '06'. SALTAB-SALDO = SKNKK-UML06. APPEND SALTAB.
  SALTAB-LNUMM = '07'. SALTAB-SALDO = SKNKK-UML07. APPEND SALTAB.
  SALTAB-LNUMM = '08'. SALTAB-SALDO = SKNKK-UML08. APPEND SALTAB.
  SALTAB-LNUMM = '09'. SALTAB-SALDO = SKNKK-UML09. APPEND SALTAB.
  SALTAB-LNUMM = '10'. SALTAB-SALDO = SKNKK-UML10. APPEND SALTAB.
  SALTAB-LNUMM = '11'. SALTAB-SALDO = SKNKK-UML11. APPEND SALTAB.
  SALTAB-LNUMM = '12'. SALTAB-SALDO = SKNKK-UML12. APPEND SALTAB.
  READ TABLE SALTAB INDEX 1.
  RF035-H06SA = SALTAB-SALDO.
  RF035-H06MO = SALTAB-LNUMM.
  RF035-H12SA = SALTAB-SALDO.
  RF035-H12MO = SALTAB-LNUMM.
------ SALTAB ---------------------------------------------
  LOOP AT SALTAB.
    IF  SALTAB-SALDO > RF035-H06SA
    AND SY-TABIX     < 7.
      RF035-H06SA = SALTAB-SALDO.
      RF035-H06MO = SALTAB-LNUMM.
    ENDIF.
    IF  SALTAB-SALDO > RF035-H12SA
    AND SY-TABIX     < 13.
      RF035-H12SA = SALTAB-SALDO.
      RF035-H12MO = SALTAB-LNUMM.
    ENDIF.
  ENDLOOP.
------ Period--------------------
  REFRESH LT_PERIODS.
  CLEAR LD_COUNTER.
  READ TABLE BUKTAB INDEX 1.
  IF SY-SUBRC = 0.
    READ TABLE GJATAB WITH KEY BUKTAB-PERIV.
    DO GJATAB-MONAT TIMES
       VARYING LD_PERIOD FROM LD_PERIODS(2) NEXT LD_PERIODS+2(2)
                                                 RANGE LD_PERIODS.
      LT_PERIODS-GJAHR  = GJATAB-GJAHR.
      LT_PERIODS-PERIOD = LD_PERIOD.
      LD_COUNTER = LD_COUNTER + 1.
      APPEND LT_PERIODS.
    ENDDO.
    IF LD_COUNTER LT 12.
      LD_GJAHR = GJATAB-GJAHR - 1.
      CLEAR T009Y.
      SELECT SINGLE * FROM T009Y WHERE PERIV = GJATAB-PERIV
                                   AND GJAHR = LD_GJAHR.
      DO GJATAB-ANZBP TIMES
         VARYING LD_PERIOD FROM LD_PERIODS(2) NEXT LD_PERIODS+2(2)
                                                   RANGE LD_PERIODS.
        IF T009Y-ANZBP > 0.
          CHECK SY-INDEX <= T009Y-ANZBP.
        ENDIF.
        LD_COUNTER = LD_COUNTER + 1.
        LT_PERIODS-GJAHR  = LD_GJAHR.
        LT_PERIODS-PERIOD = LD_PERIOD.
        APPEND LT_PERIODS.
      ENDDO.
    ENDIF.
    IF LD_COUNTER LT 12.
      LD_GJAHR = LD_GJAHR - 1.
      DO GJATAB-ANZBP TIMES
         VARYING LD_PERIOD FROM LD_PERIODS(2) NEXT LD_PERIODS+2(2)
                                                   RANGE LD_PERIODS.
        LD_COUNTER = LD_COUNTER + 1.
        LT_PERIODS-GJAHR  = LD_GJAHR.
        LT_PERIODS-PERIOD = LD_PERIOD.
        APPEND LT_PERIODS.
      ENDDO.
    ENDIF.
    SORT LT_PERIODS BY GJAHR ASCENDING PERIOD ASCENDING.
    LD_COUNTER = LD_COUNTER - 12.
    DO LD_COUNTER TIMES.
      DELETE LT_PERIODS INDEX 1.
    ENDDO.
    SORT LT_PERIODS BY GJAHR DESCENDING PERIOD DESCENDING.
    READ TABLE LT_PERIODS INDEX RF035-H06MO.
    RF035-H06MO = LT_PERIODS-PERIOD.
    RF035-H06JA = LT_PERIODS-GJAHR.
    READ TABLE LT_PERIODS INDEX RF035-H12MO.
    RF035-H12MO = LT_PERIODS-PERIOD.
    RF035-H12JA = LT_PERIODS-GJAHR.
  ENDIF.
**Compute Due Dates fields
  PERFORM GET_AGING_BUCKETS .
  RF035-SFAE1 = SKNKK-SFAE1.
  RF035-SFAE2 = SKNKK-SFAE2.
  RF035-SFAE3 = SKNKK-SFAE3.
  RF035-SFAE4 = SKNKK-SFAE4 .
  RF035-SFAE5 = SKNKK-SFAE5.
ENDLOOP.
ENDFORM.                    " GET_BALANCE_SFIELDS
*&      Form  GET_AGING_BUCKETS
      text
-->  p1        text
<--  p2        text
FORM GET_AGING_BUCKETS .
  DATA: BEGIN OF LT_BUKRS OCCURS 0,
          BUKRS LIKE T001-BUKRS,
        END OF LT_BUKRS.
  DATA: BEGIN OF LT_BUKTAB OCCURS 0,
          BUKRS LIKE T001-BUKRS,
          WAERS LIKE T001-WAERS,
          KKBER LIKE T014-KKBER,
        END OF LT_BUKTAB.
  DATA: LD_LINES LIKE SY-TABIX.
*...performance optimization: for more than one company codes check....*
*...if balances exist and avoid selection of open items, if they don't.*
*...exist..............................................................*
  REFRESH LT_BUKRS.
  REFRESH LT_BUKTAB.
  DESCRIBE TABLE BUKTAB LINES LD_LINES.
  IF LD_LINES GT 1.
    SELECT DISTINCT BUKRS APPENDING CORRESPONDING FIELDS
                                    OF TABLE LT_BUKRS
                          FROM KNC1 FOR ALL ENTRIES IN BUKTAB
                    WHERE BUKRS = BUKTAB-BUKRS AND
                          KUNNR = Sknkk-KUNNR.
    SELECT DISTINCT BUKRS APPENDING CORRESPONDING FIELDS
                                    OF TABLE LT_BUKRS
                          FROM KNC3 FOR ALL ENTRIES IN BUKTAB
                    WHERE BUKRS = BUKTAB-BUKRS AND
                          KUNNR = Sknkk-KUNNR.
    SORT LT_BUKRS.
    DELETE ADJACENT DUPLICATES FROM LT_BUKRS.
    LOOP AT LT_BUKRS.
      LOOP AT BUKTAB WHERE BUKRS = LT_BUKRS-BUKRS.
        MOVE-CORRESPONDING BUKTAB TO LT_BUKTAB.
        APPEND LT_BUKTAB.
      ENDLOOP.
    ENDLOOP.
  ELSE.
    READ TABLE BUKTAB INDEX 1.
    MOVE-CORRESPONDING BUKTAB TO LT_BUKTAB.
    APPEND LT_BUKTAB.
  ENDIF.
*...process company codes for customer given by interface..........*
  LOOP AT LT_BUKTAB WHERE KKBER = s_cinfo-KKBER.
    CALL FUNCTION  'CUSTOMER_DUE_DATE_ANALYSIS'
         EXPORTING  BUKRS   = LT_BUKTAB-BUKRS
                   KKBER   = ' '
                    KKBER   = s_cinfo-KKBER
                    KUNNR   = Sknkk-KUNNR
                    RASID   = RASID
         IMPORTING  SFAE1   = RF035-SFAE1
                    SFAE2   = RF035-SFAE2
                    SFAE3   = RF035-SFAE3
                    SFAE4   = RF035-SFAE4
                    SFAE5   = RF035-SFAE5
                    SFAEL   = RF035-SFAEL
         EXCEPTIONS NO_OPEN_ITEMS = 4.
    IF SY-SUBRC = 0.
*--  RF035 -
      SKNKK-SFAE1 = SKNKK-SFAE1 + RF035-SFAE1.
      SKNKK-SFAE2 = SKNKK-SFAE2 + RF035-SFAE2.
      SKNKK-SFAE3 = SKNKK-SFAE3 + RF035-SFAE3.
      SKNKK-SFAE4 = SKNKK-SFAE4 + RF035-SFAE4.
      SKNKK-SFAE5 = SKNKK-SFAE5 + RF035-SFAE5.
      SKNKK-SFAE5 = SKNKK-SFAE5 + RF035-SFAE5.
      SKNKK-SFAEL = SKNKK-SFAEL + RF035-SFAEL.
    ENDIF.
  ENDLOOP.
ENDFORM.                    " GET_AGING_BUCKETS
*&      Form  header
This Subroutine gets data for displaying title                     *
There are no interface parameters to be passed to this subroutine. *
FORM header .
  wa_final-string = text-000.  APPEND wa_final TO i_final.
  wa_final-string = text-001.  APPEND wa_final TO i_final.
  wa_final-string = text-002.  APPEND wa_final TO i_final.
  wa_final-string = text-003.  APPEND wa_final TO i_final.
  wa_final-string = text-004.  APPEND wa_final TO i_final.
  wa_final-string = text-005.  APPEND wa_final TO i_final.
  wa_final-string = text-006.  APPEND wa_final TO i_final.
  wa_final-string = text-007.  APPEND wa_final TO i_final.
  wa_final-string = text-008.  APPEND wa_final TO i_final.
  wa_final-string = text-009.  APPEND wa_final TO i_final.
  wa_final-string = text-010.  APPEND wa_final TO i_final.
  wa_final-string = text-011.  APPEND wa_final TO i_final.
  wa_final-string = text-012.  APPEND wa_final TO i_final.
  wa_final-string = text-013.  APPEND wa_final TO i_final.
  wa_final-string = text-014.  APPEND wa_final TO i_final.
  wa_final-string = text-015.  APPEND wa_final TO i_final.
  wa_final-string = text-016.  APPEND wa_final TO i_final.
  wa_final-string = text-017.  APPEND wa_final TO i_final.
  wa_final-string = text-018.  APPEND wa_final TO i_final.
  wa_final-string = text-019.  APPEND wa_final TO i_final.
  wa_final-string = text-020.  APPEND wa_final TO i_final.
  wa_final-string = text-021.  APPEND wa_final TO i_final.
  wa_final-string = text-022.  APPEND wa_final TO i_final.
  wa_final-string = text-023.  APPEND wa_final TO i_final.
  wa_final-string = text-024.  APPEND wa_final TO i_final.
ENDFORM.                               " header
*&      Form  DOWNLOADCREDITDATA
      text
     -->P_P_PATH  text
FORM DOWNLOADCREDITDATA  USING P_PATH.
  DATA:
      lw_file2 TYPE string .           " File Path
  lw_file2 = p_PATH.
  CALL FUNCTION 'GUI_DOWNLOAD'
     EXPORTING
  BIN_FILESIZE                    = BIN_FILESIZE
       filename                        = lw_file2
       filetype                        = 'DBF'
  APPEND                          = ' '
   write_field_separator           = ' '
  HEADER                          = '00'
  TRUNC_TRAILING_BLANKS           = 'X'
  WRITE_LF                        = 'X'
   COL_SELECT                      = 'X'
  COL_SELECT_MASK                 = ' '
  DAT_MODE                        = 'X'
  CONFIRM_OVERWRITE               = ' '
  NO_AUTH_CHECK                   = ' '
  CODEPAGE                        = ' '
  IGNORE_CERR                     = ABAP_TRUE
  REPLACEMENT                     = '#'
  WRITE_BOM                       = ' '
  TRUNC_TRAILING_BLANKS_EOL       = 'X'
  WK1_N_FORMAT                    = '0'
  WK1_N_SIZE                      = ' '
  WK1_T_FORMAT                    = ' '
  WK1_T_SIZE                      = ' '
IMPORTING
  FILELENGTH                      = FILELENGTH
     TABLES
       data_tab                        = I_CINFO
       fieldnames                      = i_final
     EXCEPTIONS
       file_write_error                = 1
       no_batch                        = 2
       gui_refuse_filetransfer         = 3
       invalid_type                    = 4
       no_authority                    = 5
       unknown_error                   = 6
       header_not_allowed              = 7
       separator_not_allowed           = 8
       filesize_not_allowed            = 9
       header_too_long                 = 10
       dp_error_create                 = 11
       dp_error_send                   = 12
       dp_error_write                  = 13
       unknown_dp_error                = 14
       access_denied                   = 15
       dp_out_of_memory                = 16
       disk_full                       = 17
       dp_timeout                      = 18
       file_not_found                  = 19
       dataprovider_exception          = 20
       control_flush_error             = 21
  IF sy-subrc <> 0.
Messege
  ENDIF.                               " IF sy-subrc EQ 0
ENDFORM.                    " DOWNLOADCREDITDATA
*&      Form  DOWNLOAD_CREDIT_DATA
      text
-->  p1        text
<--  p2        text
FORM DOWNLOAD_CREDIT_DATA .
  PERFORM HEADER.
  PERFORM DOWNLOADCREDITDATA USING P_PATH.
ENDFORM.                    " DOWNLOAD_CREDIT_DATA
*&      Form  GET_PGRESS_INDICATOR
      text
     -->P_L_TEXT  text
     -->P_L_PCT  text
FORM GET_PGRESS_INDICATOR  USING    L_TEXT
                                    L_PCT.
  CALL FUNCTION 'SAPGUI_PROGRESS_INDICATOR'
    EXPORTING
      PERCENTAGE = l_pct
      TEXT       = l_TEXT.
ENDFORM.                    " GET_PGRESS_INDICATOR

Answer 1

If you are just Downloading to a Flat file then why dont you have logic in place for the program to dump the data read into  the file to that point depending on any criteria like accounts or customer then clear the internal table and run it in the back ground.
try to use cursor to read the records from the table which will make it a bit more efficient than plain select stement.