This tutorial explains the export/import buffer profile parameters, the ESM (export/import-shared-memory) buffer, the OTR (Online Text Repository) buffer, and the CUA buffer.
The profile parameters for the dimensioning of the following buffers are explained below:
You can use the ABAP command EXPORT TO SHARED BUFFER to save data clusters in a general work process buffer, the Export/Import buffer (or shared buffer).
1. Export/Import buffer:
a) Size in the shared memory:rsdb/obj/buffersize [in kilobytes]
Default: 4,096 [kB]
Maximum: 2,097.148 [kB] for kernel Release 3.I to 6.20 with a patch number lower than 1129. Size restrictions no longer apply to releases above this level.
b) Number of the objects that can be buffered (directories): rsdb/obj/max_objects
Default: 2,000
The number of directories must be adjusted to the total size of the buffer: Each directory requires approximately 430 bytes of administrative information in the buffer. The directories should not take up more than 20% of the buffer to allow enough memory space for the objects to be buffered.
The following is a rough guideline:
The value for rsdb/obj/max_objects should not be greater than half the value of rsdb/obj/buffersize. However, this value may be higher in releases lower than 640, up to the value of rsdb/obj/buffersize, since a directory requires less memory in these releases.
If an overflow occurs, see SAP Doc 373986. If the runtime error EXPORT_BUFFER_NO_MEMORY occurs, see SAP Note 520684.
2. ESM buffer:
As of kernel Release 6.10, you have an additional new ABAP command EXPORT TO SHARED MEMORY, that you can use to save data clusters in the export/import shared memory buffer (or ESM buffer for short).
a) Size in the shared memory: rsdb/esm/buffersize_kb [in kilobytes]
Default: 4,096 [kB]
Maximum: 2,097.148 [kB] for kernel Release 3.I to 6.20 with a patch number lower than 1129. Size restrictions no longer apply to releases above this level.
b) Number of the objects that can be buffered (directories): rsdb/esm/max_objects
Default: 2,000
Note: The information in point 1-b also applies here.
3. OTR buffer:
The online text repository buffer is available as of kernel Release 6.10. Here texts are saved that are used in BSP for example.
a) Size in the shared memory: rsdb/otr/buffersize_kb [in kilobytes]
Default: 4,096 [kB]
Maximum: 2,097.148 [kB] for kernel Release 3.I to 6.20 with a patch number lower than 1129. Size restrictions no longer apply to releases above this level.
b) Number of the objects that can be buffered (directories): rsdb/otr/max_objects
Default: 2,000
Note: See point 1-b.
4. CUA buffer:
The GUI interface's runtime objects are stored in the CUA buffer. They are then saved in the database in the tables D345T, D346T, and D342L.
a) Size in the shared memory: rsdb/cua/buffersize [in kilobytes]
Default: 3,000 [kB]
Maximum: 2,097.148 [kB] for kernel Release 3.I to 6.20 with a patch number lower than 1129. Size restrictions no longer apply to releases above this level.
b) The number of directories is calculated from the buffer size and cannot/must not be set explicitly using a profile parameter.
Caution:
Take the following points into consideration if you are increasing the buffer parameters in the SAP profile:
- Your system must have enough main memory. The main memory is limited, especially on 32-bit platforms, so any buffer increase must align with existing memory management.
- We cannot prescribe definite guide values for optimal buffer sizes. The appropriate sizes depend on the hardware, release level, dataset in the system, and applications used.
- You must restart the system for the profile change to take effect.
- Once the adjustment has taken place, we recommend that you use transaction ST02 to check the buffer after a short while.