Parallel processing using ABAP objects

Question

Hello friends,
                    I had posted in the performance tuning forum , regarding a performance issue problem , I am reposting it as it involves OO concept .
the link for the previous posting
Link: [Independent processing of elements inside internal table;
Here is the scenario,
I have a internal table with 10 records(indepentent) , and i need to process them .The processing of one record doesnt have any influence on the another . When we go for loop , the performance issue is that , the 10 th record has to wait until the 9 records get processed even though there is no dependency on the output.
Could some one tell a way out to improve the performance..
If i am not clear with the question , i would explain it still clearer...
A internal table has 5 numbers , say( 1,3,4,6,7)
we are trying to find square of each number ,,,
If it is a loop the finding of suare of 7 has to wait until 6 is getting completed and it is waste of time ...
This is related to parallel processing , I have refered to parallel processing documents,But I want to do this conceptually ..
I am not using conventional procedural paradigm but Object orientedness...I am having a method which is performing this action .What am I supposed to do in that regard.
Comradely ,
K.Sibi

Answer 1

Hi,
As examplified by Edward, there is no RFC/asynchronous support for Methods of ABAP Objects as such. You would indeed need to "wrap" your method or ABAP Object in a Function Module, that you can then call with the addition "STARTING NEW TASK". Optionally, you can define a Method that will process the results of the Function Module that is executed asynchronously, as demonstrated as well in Edward's program.
You do need some additional code to avoid the situation where your program takes all the available resources on the Application Server. Theoretically, you cannot bring the server or system down, as there is a system profile parameter that determines the maximum number of asynchronous tasks that the system will allow. However, in a productive environment, it would be a good idea to limit the number of asynchronous tasks started from your program so that other programs can use some as well.
Function Group SPBT contains a set of Function Modules to manage parallel processing. In particular, FM SPBT_INITIALIZE will "initialize" a Server Group and return the maximum number of Parallel Tasks, as well as the number of free ones at the time of the initialization. The other FM of interest is SPBT_GET_CURR_RESOURCE_INFO, that can be called after the Server Group has been initialized, whenever you want to "fork" a new asynchronous task. This FM will give you the number of free tasks available for Parallel Processing at the time of calling the Function Module.
Below is a code snippet showing how these Function Modules could be used, so that your program always leaves a minimum of 2 tasks for Parallel Processing, that will be available for other programs in the system.
      IF md_parallel IS NOT INITIAL.
        IF md_parallel_init IS INITIAL.
*----- Server Group not initialized yet => Initialize it, and get the number of tasks available
          CALL FUNCTION 'SPBT_INITIALIZE'
          EXPORTING
            GROUP_NAME                           = ' '
            IMPORTING
              max_pbt_wps                          = ld_max_tasks
              free_pbt_wps                         = ld_free_tasks
            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.
          md_parallel_init = 'X'.
        ELSE.
*----- Server Group initialized => check how many free tasks are available in the Server Group
      for parallel processing
          CALL FUNCTION 'SPBT_GET_CURR_RESOURCE_INFO'
            IMPORTING
              max_pbt_wps                 = ld_max_tasks
              free_pbt_wps                = ld_free_tasks
            EXCEPTIONS
              internal_error              = 1
              pbt_env_not_initialized_yet = 2
              OTHERS                      = 3.
        ENDIF.
        IF ld_free_tasks GE 2.
*----- We have at leasr 2 remaining available tasks => reserve one
          ld_taskid = ld_taskid + 1.
        ENDIF.
    ENDIF.
You may also need to program a WAIT statement, to wait until all asynchronous tasks "forked" from your program have completed their processing. Otherwise, you might find yourself in the situation where your main program has finished its processing, but some of the asynchronous tasks that it started are still running. If you do not need to report on the results of these asynchronous tasks, then that is not an issue. But, if you need to report on the success/failure of the processing performed by the asynchronous tasks, you would most likely report incomplete results in your program.
In the example where you have 10 entries to process asynchronously in an internal table, if you do not WAIT until all asynchronous tasks have completed, your program might report success/failure for only 8 of the 10 entries, because your program has completed before the asynchronous tasks for entries 9 and 10 in your internal table.
Given the complexity of Parallel Processing, you would only consider it in a customer program for situations where you have many (ie, thousands, if not tens of thousands) records to process, that the processing for each record tends to take a long time (like creating a Sales Order or Material via BAPI calls), and that you have a limited time window to process all of these records.
Well, whatever your decision is, good luck.