Tuning SAP Buffers

Definiton It is beneficial to keep as much data buffered as possible. This helps avoid repetitive database accesses, for example from the network and Interprocess Communication (IPC), and maximize system performance.
Reduced performance is caused by

• Buffers set too small.

The required data cannot be stored in the buffers. Instead, objects have to be swapped out of the buffers. This causes expensive database accesses.

• Buffers set too large

Memory is wasted. Paging may occur if too much memory is taken from the operating system and allocated to the SAP buffers and database. You should check regularly whether the buffer size is suited to your system requirements. Since buffers are crucial for the performance of the SAP System, all buffers (except the SAP cursor cache) should be adjusted to their optimal value.
The optimum size for each buffer depends largely on the specific configuration of the server, that is, the applications, the number of users working in each module, and so on. Therefore, it is difficult to specify values suitable for all configurations. The most important criterion for the correct buffer size is the buffer quality.

You should not adjust buffers in cases where poor buffer quality is due to special circumstances, for example, object swaps in the program buffer in a system with a high level of development activity. Buffer Tuning Checklist If there is insufficient memory to set the appropriate buffer sizes, you should consider adding physical memory. However, since this could take some time, you may have to decide which buffers are most important and should be adjusted first using the existing memory.
As a guideline, the most important buffers are those that:

• Are responsible for good dialog performance
• Are used most frequently
• Require relatively few memory resources

These criteria give you the following priority list:

1. Repository buffers (nametab buffers)
2. Table buffers
3. Program buffers
4. Roll and page file buffers
5. SAPgui buffers

See also:
High Buffer Quality
How Much Operating System Paging is Acceptable?
Directory Space and Data Space
Adjusting Pool Sizes
Special Aspects of Tuning