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Sunday, 5 January 2014

ST02 – SAP Tuning

Buffer: The first column shows the names of the buffers:

·        Four ABAP repository buffers.
·        The program, CUA, screen, and calendar buffers.
·        The table buffers.
Hit Ratio: 
A hit is when an object (such as a table, screen, or program) in the buffer is accessed. If the object has to be read from the database, the buffer access fails.
Allocated Size:
The allocated size is measured in KB. It is different from the available buffer size because a part of the size is used for buffer management.
Freespace :     
Freespace is important for analyzing the buffer size. The space remaining in the buffer is displayed in KB and percentage of the available buffer size.
Number of Directories:
Even though there is freespace in the buffer, objects may not always be loaded into the buffer because there are no more free directories. The Buffers Monitor displays the number of directories available for the buffer, and the number and percentage free. The buffer directories point to the location of the objects that are located in the buffer.
When a buffer has insufficient freespace or free directories, it has to swap objects out of the buffer in order to load a new object. The column Swap shows how many objects have been swapped out since system startup.
Database Accesses
When an object cannot be read from the buffer, the database has to be accessed. The number of database accesses is displayed in the last column of this screen.

click on Current Parameter