(sap)parameters for Export/import buffer instances

zhangpengfei00

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. All together, 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 also, since a directory requires less memory in these releases.
If an overflow occurs, see Note 373986. If the runtime error EXPORT_BUFFER_NO_MEMORY occurs, see Note 520684.