In REUSE_ALV_GRID_DISPLAY, significance of I_BUFFER_ACTIVE !

Question

Hi All,
We have a Report prog, which is shceduled as Batch Job.
Now what happens is this batch  job gets cancelled due to lack of memory
Below is the FM used in the prog.
    CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
         EXPORTING
              I_BUFFER_ACTIVE    = 'X'
              I_CALLBACK_PROGRAM = G_REPID
              IS_LAYOUT          = GS_LAYOUT
              IT_FIELDCAT        = GT_FIELDCAT[]
              IT_EVENTS          = GT_EVENTS[]
         TABLES
              T_OUTTAB           = P_GT_OUTTAB
         EXCEPTIONS
              PROGRAM_ERROR      = 1
              OTHERS             = 2.
    IF SY-SUBRC <> 0.
      MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
              WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
    ENDIF.
Now what i noticed is I_BUFFER_ACTIVE is 'X' in the FM REUSE_ALV_GRID_DISPLAY
What is the significance of this parameter ?
Will my problem solve if i set I_BUFFER_ACTIVE to ''.
Any suggestions are invited.
Thanks!

Answer 1

Hi,
Essentially, the ALV uses a two-step buffer concept for performance reasons.
Buffer A:
Complete variants including field catalog, sorting, filter
static field catalog (shared buffer)
Buffer B:
DDIC information for each field of the field catalog (Shared Buffer + Memory)
Optimized access to field catalog (Shared Buffer + Memory)
With parameter I_BUFFER_ACTIVE = 'X', buffer A is activated.If I_BUFFER_ACTIVE remains initial, the contents are nevertheless buffered in buffer B. For dynamic reasons, you have to forgo buffering completely (for example, a constant dynamic creation of structures) so that you have the following options as a developer:
1. Set SET/GET parameters ALVBUFFER to the current date.All report, variant or field catalog buffers are reset until the current date exceeds the date of the SET/GET parameter.
2. Set I_BYPASSING_BUFFER = 'X' on the call interface for the function modules and class methods.
Which type of buffering can I use for which scenario? (=developer view)
1. Activate the statically constant field catalog of buffer A with I_BUFFER_ACTIVE = 'X'
2. Semi-statically constant field catalog, for example different columns are displayed and hidden for each call.Call ALV normally, optimization is carried out implicitly by using buffer B.
3. Dynamically generated structures with field enhancements or text element changes for data elements.
How can I influence or refresh the buffers?
1. Refresh once after the structure change in a system by, for example, importing the transport request:
Set the SET/GET parameter ALVBUFFER to the current date
Execute the affected transaction/report
Delete the SET/GET parameter ALVBUFFER
Restart in a new session ( !)
2. If refreshing over a longer time of development, static scenario should be implemented in production operation
Set the SET/GET parameter ALVBUFFER to a date in the future
3. If buffer A causes problems, it can be deactivated centrally by setting the static class attribute CL_GUI_ALV_GRID=>M_BUFFER_INACTIVE='X'.
4. If you want to reset all buffers (A and B) once and centrally for all ALV applications, then execute report BALVBUFDEL.With the option "Only delete EUINFO(%F)/LTDX", all ALV buffers are reset on the current application.Then execute your report/transaction in a new session.After you have imported note 378021 or the appropriate Support Package, the entries are deleted from the selection screen and the report automatically deletes the ALV area of all active application servers.
Hope, this helps....
Regards,
Vinod