Buffer: Hit rate

What causes this issue?

This monitoring tree element (MTE) shows the hit ratio of a buffer. The
hit ratio is a measure of the quality or performance of the buffer. It
is the percentage of database requests that could be satisfied from the
buffer, without requiring the involvement of the database.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Hit ratio alerts mean that poor buffer performance is reducing the
performance of the application server. The buffers in the alert monitor
are critical to good instance performance. You should therefore analyze
the buffer quality problem and take corrective action.
In general, poor buffer quality means that a buffer is too small. If a
buffer is too small, then the chances increase that requested objects
(table entries, programs, and so on) will not be found in it. The
result is a lower hit ratio, and, if the buffer is already full,
increased swapping. Swapping increases as requested objects force older
objects out of the buffer.
To improve the hit ratio, you should generally increase the size of a
buffer.
Use the analysis method for this buffer to analyze the performance of
the buffer before you enlarge it. Be sure that no temporary problem has
reduced the buffer's quality. (All buffers perform poorly during a
warm-up phase after the system or an application server starts. The
monitoring architecture does not issue buffer alerts during a best-guess
warm-up period).
Further, the performance of the program buffer may be reduced if
developers are working in a system or if objects are being imported into
the system with the SAP transport system.
<DS:TX.SMOI_BUFFER_MANAGEMENT_INFO>Background Information</>
See also the descriptive message for buffer free space and the CCMS
Guide under Help -> SAP Library -> SAP NetWeaver -> System Life Cycle
Management -> Solution Monitoring -> Monitoring in the CCMS.

Error message extract from SAP system. Copyright SAP SE.