If the required data is in the R/3 buffers on the application server, accessing them requires approximately 0.1 milliseconds for each data record.
If the data records are read from the database buffer, around 1 millisecond is required.
When the data is read from the disk, this requires approximately 10 milliseconds for each data record.
Memory Allocation in SAP
An R/3 work process allocates around 5 MB of memory.
The R/3 table buffers allocate approximately 120 MB (40 MB for single record buffers, 80 MB for generic table buffers).
The data buffers of the database use around 500 MB of memory. The database on the disks can reach a size of several terabytes.
The data transfer between front end and application server occurs in blocks of 2 KB.
The transfer between application server and database server occurs in blocks of up to 32 KB.了解了上面的一些数据，对数据优化有好处。
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