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performance question

Former Member
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What does it mean when you have very good hit ratios on your buffers say 99.99 % and the system has been running say 3-4 weeks without a reboot and has heavy usage/

The PXA buffer is showing like 2 million swaps.

Field Definition and initial records buffers show 1/2 mil swaps or so

and Export import show a whopping 9 million swaps

Any suggestions here?

Accepted Solutions (0)

Answers (2)

Answers (2)

Former Member
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Hi

The values above indicates that there is problem with the size of the buffers.

Swapping occurs when the buffer is full, and the SAP System has to load additional objects into the buffer. Objects in the buffer that were used the least recently are removed. In this context, the term "swap" means the objects removed from the buffer are lost and cannot be replaced until a new database access is performed (replacing what was lost).

There are two possible reasons for swapping

1.There is no space left in the buffer data area

The buffer is too small. You should increase the buffer size.

2. There are no directory entries left

Although there is enough space left in the buffer, no further objects can be loaded because the number of directory entries is limited.

Before you change the size of a buffer, you should determine how much memory the buffer is currently allocated. This is important because the memory that is allocated to buffers should not significantly exceed the size of the physical memory, otherwise operating system swapping will occur.

Check out with the size of these buffers.

Regards

Sumit Jain

**Reward points if you find it useful

Former Member
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Possibly low Buffer area allocation for "Program" Buffer area.

To increase the size of a buffer, change the system profile parameters that specify the size of the buffer. For some buffers, you can set the size of the buffer and the maximum number of entries in separate parameters. For other buffers, there is only a size parameter, and the system automatically calculates the required system parameters

check out

http://help.sap.com/saphelp_nw2004s/helpdata/en/bc/4a813b680c250fe10000000a114084/frameset.htm to set buffer sizes.

This might not be the reason though but just could be one of the possibilities.