Remark on program buffer (abap/buffersize):Area-dependent: I II IIIrsdb/ntab/ftabsize 20000 30000 30000 !!!zcsa/presentation_buffer_area 15000000 20000000 20000000abap/buffersize 240000 240000 400000Current abap/buffersize 900 MbAverage Swaps 9000 /dayIn most cases a program buffer with 240 MByte is not sufficient for Release 4.0/4.5. Therefore, if necessary, it should be enlarged during the production operation Also, observe the "swaps" in the program buffer in Transaction ST02. Some 1,000 swaps a day can be tolerated, but if you find more than 10,000 swaps a day, the buffer should be enlarged. Note that imports of ABAP programs cause buffer fragmentation and consequently swaps. To avoid this, reduce the number of transports into your production system.The enlargement of program buffers (abap/buffersize) can cause problems in the memory administration:AIX: Note 98084 "AIX: ABAP programm buffer PXA larger than 256MB"The buffer sizes specified are standard installation values. After the production startup, you have to adjust the parameters to the actual requirements. To do this, call Transaction ST02. If displacements occur in the "Swaps" column, you should enlarge the buffers in question (however, note that up to 10,000 swaps may occur in the program buffer).ParametersAbap/pxa = shared (Default setting: do not change)Parameter abap/programs is automatically calculated.--------------- 100For parameter abap/pxa=shared, the calculation formula abap/programs = abap/buffersize DIV 8 is used.abap/program = 900 /8 = 112.5If parameter abap/programs is set explicitly in the instance profile, and the calculation formula returns a value larger than 8KB, abap/programs is automatically set to abap/buffersize DIV 8. This ensures that a directory entry exists for every 8KB in the buffer.Parameter abap/buffersize determines the program buffer size in KB (1024 bytes). In the R/3 System, the program buffer is administered with the SHM key 06. See also: parameter ipc/shm_psize_06.Parameter abap/pxa_preload (default: 60) determines the fill level of the program buffer when the instance is started. The preload phase is stopped at 60% (default: abap/pxa_preload=60).NOTE: This parameter can be changed, even if it is not documented. Changing the parameter creates an error message when the profile is checked using the Transaction RZ10. The message displays the change as an unknown parameter.Using parameter ipc/shm_psize_06, the program buffer can be set for UNIX systems outside of an SHM pool (ipc/shm_psize_06 = 0) or in the SHM pool 10 (ipc/shm_psize_06 = -10). The parameter has no effect on operating systems other than UNIX, because SHM pools are only implemented for UNIX.The parameters in this article should not be set in DEFAULT.PFL.The Dispatcher Administration buffer (Key 02) and the program buffer (Key 06) must be in the same SHM pool (only for UNIX). Example:either: ipc/shm_psize_02 = 0 and ipc/shm_psize_06 = 0or: ipc/shm_psize_02 = -10 and ipc/shm_psize_06 = -10LimitationsFor other operating systems, the maximum program buffer size is dependent upon the following sizes: Maximum size of the operating system, approximately 2GB Maximum SHM segment size of the operating system and, for UNIX systems except AIX, the actual value set in the kernel (UNIX kernel parameter SHMMAX) If the program buffer is in pool 10, these limitations apply to SHM pool 10 (ipc/shm_psize_10)If the program buffer setting is significantly different from the correct setting, the R/3 instance uses an emergency setup (4000KB buffer, 500 programs). The instance can be started, but due to the permanent displacement in the buffer high-performance operation of is not possible See also OSS Note 77833.