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Swaps in Tune summary

former_member222381
Participant
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Hi Experts,

As i am new to Basis job and m unable to analyse as how to analyse the swaps in ST02.

Can anyone please let me know as how to analyse the swaps and what parameters i have to increase.?

Please find the attachment for swaps in Tune Summary and give the suggestion...

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Answers (2)

Answers (2)

former_member183707
Participant
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Hi Team,

As you are seeing in swap column that currently it's 6 red color mark swaps. it should not be more than 8-10.

it's daily monitoring task.

Regards,

Nilesh Vangujar

Former Member
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Hello Nilesh,

For object swaps in ST02 you can apply following rule of thumb:

- The NTAB buffers (these are the buffers listed at the top: Table Definition, Field Definition, Short NTAB and Initial records: here the aim is zero swaps

- Program buffer (often called the "PXA" in notes and technical articles): unless the buffer is oversized, you will almost always see swaps here. A rate of 1000 per day is acceptable (even somewhat higher - I have seen documents stating that 5000 is still OK but I tend to be a bit more conservative).

- Other buffers: zero swaps is ideal, a small number of swaps is acceptable, unless you see that the buffer or its directory is almost full. You will often see a low number of swaps for the Generic Key and Single Record Table Buffers.

- Careful with the Export/Import Buffer: make sure this buffer has plenty of free space, because in my experience the number of swaps explodes (I've seen hundreds of thousands per day in severe cases) if the buffer becomes full.

Obviously, object swaps are not the only buffer metric in ST02 that you should monitor. Also keep an eye on the free space and the directory free entries; enlarge the buffer proactively if free space becomes scarce.

Regards,

Mark

former_member183707
Participant
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Hi Mark,

Thank you for the sharing valuable knowledge.!!

Best Regards,

Nilesh

yakcinar
Active Contributor
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Hello RKR,

There were note 1918603 - High swaps in transaction ST02 before. This seems obsolete now. I copiedthe note from my documents below.

Check this link also.by Mauricio Grisa

Environment

SAP NetWeaver

Reproducing the Issue

Usually there is no specific way to reproduce this type of issue.

Cause

This issue is usually caused because the values of the related buffer parameters are not large enough.

Resolution

A few thousand swaps might be tolerated in transaction ST02. However, It is necessary to increase the values of the related buffer parameters if the amount of swaps is too high. Then keep monitoring the system and check if the high number of swaps persists. If it does, it is necessary to increase the values again until the swaps are gone.

Each buffer has a related parameter. Below there is a list of notes that are related to each buffer:

  • Nametab buffer (Table definition, Field definition, Short NTAB, Initial records): check SAP Notes 16244 and 1398802.
  • Program buffer: check SAP Notes 552778 and 147568.
  • CUA, Screen, Calendar, OTR,  buffers: check SAP Note 702728.
  • Tables buffer (Generic Key, Single record): check SAP Notes 8778 and 480710.
  • Export/import buffer: check SAP Notes 373986 and 702728.
  • Exp./ Imp. SHM buffer: check SAP Note 702728.

NOTE: It is not possible to suggest a precise value for the buffer sizes. The sizes depend on the update level, amount of data in the system, the applications used, etc. In general, the buffer must always be set as large as necessary to avoid swaps.

See Also

SAP Note 103747: Performance: Parameter recommendations as of Release 4.0

Keywords

TTAB, Table description, FTAB, Field catalog, Short nametab, Initial record, Profile, Shared Buffer, PXA, Overflow, Table buffer, Single record buffer, CUA buffer, Maximum buffer size

Regards,

Yuksel AKCINAR