Author: Clemens Li
Submitted: 20071202
Related Links:
Easily implement parallel processing in online and batch processing
From time to time I faced the problem of slow performance and/or too much use of temporarily needed memory storage space.
One possible solution is to slit up the whole task into packages that may be processed online or in background. This will not necessarily save any time. Also we face the problem of collecting the results in one single list or whatever form of output we choose.
The next approach is parallel processing: If we create background jobs and let tthe operating system schedule the run as soon as possible, we have the administrative task of checking all Jobs have finished their run successfully. Then, as mentioned, the collecting and combining results store in spool lists or in other locations.
ABAP allows to use the of CALL FUNCTION func ...STARTING NEW TASK task name.
This allows to process several packages in parallel. The addition ... PERFORMING form ON END OF TASK allows to receive the results.
Unfortunately, the documentation on this is not much and a couple of questions and searches in the ABAP forums did not give sufficient answers.
It looks comparably easy to create an RFC function module to process packages of the whole workload and start it parallel in a task group using ... DESTINATION IN GROUP group name.
According to documentation, asynchronous RFC calls are processed by dialog tasks. This implies the same time limits (usually 5 minutes) apply here as in 'normal' online work. And, because the number of available tasks is limited, this time may be easily exceeded.
After doing some experimental work I found out that after dispatching packets to the available tasks, the program must execute the WAIT statement to enable the PERFORMING form ON END OF TASK take effect and the form being executed.
Finally I created a sample program including a small class for the task handling. It is just a test program using the BAPI function BAPI_BILLINGDOC_GETLIST' retrieving packets determined by ranges of document numbers. It can be easily remodeled to handle anything.
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*&---------------------------------------------------------------------*
*& Report ZZZPARTEST *
*& *
*&---------------------------------------------------------------------*
*& *
*& *
*&---------------------------------------------------------------------*
REPORT zzzpartest.
PARAMETERS:
p_dbcnt TYPE sydbcnt DEFAULT 1010,
p_pacsz TYPE sydbcnt DEFAULT 95.
CONSTANTS:
gc_function TYPE tfdir-funcname
VALUE 'BAPI_BILLINGDOC_GETLIST'.
DATA:
gt_bapivbrksuccess TYPE TABLE OF
bapivbrksuccess,
gv_activ TYPE i,
gv_rcv TYPE i,
gv_snd TYPE i,
BEGIN OF ls_intval,
task TYPE numc4,
idxfr TYPE i,
idxto TYPE i,
activ TYPE flag,
fails TYPE i,
END OF ls_intval,
gt_intval LIKE TABLE OF ls_intval.
START-OF-SELECTION.
PERFORM paralleltest.
*---------------------------------------------------------------------*
* CLASS task DEFINITION
*---------------------------------------------------------------------*
* ........ *
*---------------------------------------------------------------------*
CLASS task DEFINITION.
PUBLIC SECTION.
CLASS-METHODS:
provide
RETURNING
value(name) TYPE numc4,
return
IMPORTING
name TYPE numc4,
initialize
RETURNING
value(group) TYPE rzllitab-classname.
PRIVATE SECTION.
CLASS-DATA:
gv_group TYPE rzllitab-classname,
BEGIN OF ls_task,
name TYPE numc4,
used TYPE flag,
END OF ls_task,
gt_task LIKE TABLE OF ls_task.
ENDCLASS. "itab DEFINITION
*** CLASS itab IMPLEMENTATION ***
CLASS task IMPLEMENTATION.
METHOD initialize.
DATA:
lv_max TYPE i,
lv_inc TYPE numc7,
lv_free TYPE i.
CLEAR gt_task.
COMMIT WORK."start new LUW?
SELECT classname
INTO gv_group
FROM rzllitab UP TO 1 ROWS
WHERE grouptype = 'S'.
ENDSELECT.
CALL FUNCTION 'SPBT_INITIALIZE'
EXPORTING
group_name = gv_group
IMPORTING
max_pbt_wps = lv_max
free_pbt_wps = lv_free
EXCEPTIONS
invalid_group_name = 1
internal_error = 2
pbt_env_already_initialized = 3
currently_no_resources_avail = 4
no_pbt_resources_found = 5
cant_init_different_pbt_groups = 6
OTHERS = 7.
IF sy-subrc <> 0.
MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
ENDIF.
SUBTRACT 2 FROM lv_free.
IF lv_free >= 1.
DO lv_free TIMES.
ls_task-name = sy-index.
APPEND ls_task TO gt_task.
ENDDO.
group = gv_group.
MESSAGE s000(r1)
WITH
'Parallel processing uses'
lv_free
'processes in group'
gv_group.
* & & & &
ELSE.
MESSAGE e000(r1)
WITH
'Parallel processing canceled,'
lv_free
'processes in group'
gv_group.
* & & & &
ENDIF.
ENDMETHOD. "initialize
METHOD provide.
FIELD-SYMBOLS:
<task> LIKE ls_task.
IF gv_group IS INITIAL.
MESSAGE e000(r1)
WITH 'Task group not initialized'.
ENDIF.
LOOP AT gt_task ASSIGNING <task>
WHERE used IS initial.
EXIT.
ENDLOOP.
CHECK sy-subrc = 0.
<task>-used = 'X'.
name = <task>-name.
ENDMETHOD.
METHOD return.
LOOP AT gt_task INTO ls_task
WHERE
name = name
AND used = 'X'.
DELETE gt_task.
ENDLOOP.
IF sy-subrc = 0.
CLEAR ls_task-used.
APPEND ls_task TO gt_task.
ELSE.
* fatal error
ENDIF.
ENDMETHOD.
ENDCLASS. "itab IMPLEMENTATION
*&---------------------------------------------------------------------*
*& Form paralleltest
*&---------------------------------------------------------------------*
FORM paralleltest.
DATA:
ls_bapi_ref_doc_range TYPE bapi_ref_doc_range,
lv_done TYPE flag,
lv_group TYPE rzllitab-classname,
lv_task TYPE numc4,
lv_msg TYPE text255,
lv_grid_title TYPE lvc_title,
lv_tfill TYPE sytfill,
lv_vbelv TYPE vbelv,
lv_npacs TYPE i,
lt_vbelv TYPE SORTED TABLE OF vbelv
WITH UNIQUE KEY table_line,
lv_mod TYPE i.
FIELD-SYMBOLS:
<intval> LIKE LINE OF gt_intval.
* build intervals
SELECT vbelv INTO lv_vbelv
FROM vbfa.
INSERT lv_vbelv INTO TABLE lt_vbelv.
CHECK sy-subrc = 0.
ADD 1 TO lv_tfill.
CHECK:
p_dbcnt > 0,
lv_tfill >= p_dbcnt.
EXIT.
ENDSELECT.
DESCRIBE TABLE lt_vbelv LINES lv_tfill.
IF (
p_pacsz < p_dbcnt OR
p_dbcnt = 0
) AND
p_pacsz > 0.
* p_dbcnt > 0 ).
lv_npacs = lv_tfill DIV p_pacsz.
lv_mod = lv_tfill MOD p_pacsz.
IF lv_mod <> 0.
ADD 1 TO lv_npacs.
ENDIF.
DO lv_npacs TIMES.
ls_intval-idxfr = ls_intval-idxto + 1.
ls_intval-idxto = ls_intval-idxfr - 1
+ p_pacsz.
IF ls_intval-idxto > lv_tfill.
ls_intval-idxto = lv_tfill.
ENDIF.
APPEND ls_intval TO gt_intval.
ENDDO.
ELSE.
ls_intval-idxfr = 1.
ls_intval-idxto = lv_tfill.
APPEND ls_intval TO gt_intval.
ENDIF.
WHILE lv_done IS INITIAL.
* find an interval to be processed
LOOP AT gt_intval ASSIGNING <intval>
WHERE activ = space
AND fails BETWEEN 0 AND 5.
EXIT.
ENDLOOP.
IF sy-subrc <> 0.
* no inactive unprocessed interval. All complete or must wait?
* check for intervals with unsuccesful tries
LOOP AT gt_intval ASSIGNING <intval>
WHERE fails BETWEEN 0 AND 5.
EXIT.
ENDLOOP.
IF sy-subrc = 0.
* wait until all started processes have been received.
* Note: No receive is executed without WAIT
WAIT UNTIL gv_activ IS INITIAL UP TO 600 SECONDS.
ELSE.
* all done
lv_done = 'X'.
ENDIF.
UNASSIGN <intval>.
ENDIF.
* process interval if provided
IF <intval> IS ASSIGNED.
WHILE lv_task IS INITIAL.
IF lv_group IS INITIAL.
* init parallel processing
lv_group = task=>initialize( ).
ENDIF.
* get unused task
lv_task = task=>provide( ).
CHECK lv_task IS INITIAL.
* no unused task? wait for all started task are received
WAIT UNTIL gv_activ IS INITIAL UP TO 600 SECONDS.
ENDWHILE.
* call if task assigned
CHECK NOT lv_task IS INITIAL.
* prepare function parameters
ls_bapi_ref_doc_range = 'IBT'.
READ TABLE lt_vbelv INTO ls_bapi_ref_doc_range-ref_doc_low
INDEX <intval>-idxfr.
READ TABLE lt_vbelv INTO ls_bapi_ref_doc_range-ref_doc_high
INDEX <intval>-idxto.
* mark interval as failed
ADD 1 TO <intval>-fails.
ADD 1 TO gv_snd.
CALL FUNCTION gc_function
STARTING NEW TASK lv_task
DESTINATION IN GROUP lv_group
PERFORMING bapi_receive ON END OF TASK
EXPORTING
refdocrange = ls_bapi_ref_doc_range
EXCEPTIONS
communication_failure = 1 MESSAGE lv_msg
system_failure = 2 MESSAGE lv_msg
RESOURCE_FAILURE = 3.
IF sy-subrc = 0.
<intval>-activ = 'X'.
<intval>-task = lv_task.
ADD 1 TO gv_activ.
ELSE.
CALL METHOD task=>return EXPORTING name = lv_task.
ENDIF.
CLEAR lv_task.
ENDIF.
ENDWHILE.
* wait for pending processes
MESSAGE s000(r1) WITH 'Wait for pending processes'.
WAIT UNTIL gv_activ IS INITIAL.
* report unfinished intervals
LOOP AT gt_intval ASSIGNING <intval>
WHERE fails >= 0.
READ TABLE lt_vbelv INTO ls_bapi_ref_doc_range-ref_doc_low
INDEX <intval>-idxfr.
READ TABLE lt_vbelv INTO ls_bapi_ref_doc_range-ref_doc_high
INDEX <intval>-idxto.
MESSAGE i000(r1)
WITH
'unprocessed interval from'
ls_bapi_ref_doc_range-ref_doc_low
'to'
ls_bapi_ref_doc_range-ref_doc_high.
ENDLOOP.
MESSAGE s000(r1) WITH 'start ALV'.
* transfer results to standard table
WRITE gv_rcv TO lv_grid_title LEFT-JUSTIFIED.
lv_grid_title+40(1) = '+'.
WRITE gv_snd TO lv_grid_title+50 LEFT-JUSTIFIED.
REPLACE '+' WITH 'RCV/SND' INTO lv_grid_title.
CONDENSE lv_grid_title.
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
EXPORTING
i_structure_name = 'BAPIVBRKSUCCESS'
i_grid_title = lv_grid_title
TABLES
t_outtab = gt_bapivbrksuccess.
ENDFORM. " paralleltest
*&---------------------------------------------------------------------*
*& Form bapi_receive
*&---------------------------------------------------------------------*
FORM bapi_receive USING pv_task TYPE any.
DATA:
lv_task TYPE numc4,
lt_bapivbrksuccess TYPE TABLE OF bapivbrksuccess,
lv_msg TYPE text80,
lv_subrc TYPE sy-subrc.
FIELD-SYMBOLS:
<intval> LIKE LINE OF gt_intval.
CLEAR lt_bapivbrksuccess.
RECEIVE RESULTS FROM FUNCTION gc_function
TABLES
success = lt_bapivbrksuccess
EXCEPTIONS
communication_failure = 1 MESSAGE lv_msg
system_failure = 2 MESSAGE lv_msg .
lv_subrc = sy-subrc.
lv_task = pv_task.
CALL METHOD task=>return EXPORTING name = lv_task.
LOOP AT gt_intval ASSIGNING <intval>
WHERE task = lv_task
AND fails <> -1.
EXIT.
ENDLOOP.
IF sy-subrc <> 0.
* fatal error
MESSAGE e000(r1)
WITH 'returned task' lv_task 'not in task table'.
ENDIF.
CLEAR <intval>-activ.
CASE lv_subrc.
WHEN 0.
<intval>-fails = -1.
APPEND LINES OF lt_bapivbrksuccess TO gt_bapivbrksuccess.
ADD 1 TO gv_rcv.
WHEN 1.
ADD 1 TO <intval>-fails.
WRITE: 'communication_failure for task', lv_task, lv_msg.
WHEN 2.
WRITE: 'system_failure', lv_task, lv_msg.
ADD 1 TO <intval>-fails.
ENDCASE.
SUBTRACT 1 FROM gv_activ.
ENDFORM. " bapi_receive