SWAP - ST02

Hi Gurus, I am doing daily monitoring for a server. Right in ST02 t-code i have some issue which i dont know how to resolve it.
One of the buffer which is Table Definition buffer directory is getting filled and increase day by day.
Buffer HitRatio % Alloc. KB Freesp. KB % Free Sp. Dir. Size FreeDirEnt % Free Dir Swaps DB Accs
Table definition 99.69 4,924 8 0.21 20,000 40 0.20 0 0 74,946
Day by day the directory size is just keep increasing. I dont have confident to tune-up the parameter setting in Production system. Even when i checked the Program buffer free directory size is 0.40% at the moment. I also have monitor that occuring in the program buffer day by day. From yesterday until today the swap that was occured was 24560 swaps. So i need your guideline what to do next in regards to this. I would sincerely appreciate your kind guidance and help.
Thank You.

Hi
Go through following links for ST02 & ST03 in sap help portal. it will give you fair idea of memnory management and work load analysis.
[Link1|http://help.sap.com/saphelp_nw70/helpdata/EN/02/96263e538111d1891b0000e8322f96/content.htm]
[Link2|http://sap.ittoolbox.com/groups/technical-functional/sap-basis/high-rollwait-time-1514656?cv=expanded]
[Link3|http://help.sap.com/saphelp_nw70/helpdata/EN/95/8a393c3ab01224e10000000a11405a/content.htm]
Regards
Uday

Similar Messages

Swaps-st02 are in red colour

R/s All,
In my Production Server (ECC6DB2 v.9.1Win2k3x64 with 40 GB of physical memory) when i perform st02 the field definition,initial records,program,CUA,generic key,export/import,buffer shows value RED under the swap category. Current memory parameters values are as follows. Kindly help us to reslove the problme.
ztta/roll_area -                                   6500000
ztta/roll_first -                                    1
ztta/short_area-                                 4000000
rdisp/ROLL_SHM-                              32768
rdisp/PG_SHM -                                  49152
rdisp/PG_LOCAL -                              150
em/initial_size_MB-                              16285
em/blocksize_KB-                                4096
em/address_space_MB-                     4096
ztta/roll_extension -                             2000000000
abap/heap_area_dia-                           2000000000
abap/heap_area_nondia-                     0
abap/heap_area_total-                         12881756160
abap/heaplimit -                                     40000000
regards,
VM

A red field in ST02 is NOT necessarily a problem. If you have performance problems and you can link them to buffer issues THEN it is a problem.
The only productive systems i have seen so far with no red buffers at all were either not having much activity or the setup was wasting hundreds mb of memory. I recommend to consider the hit ratio as well. If for example your program buffer is above 99%, there is no need to further increase it.
Cheers Michael

ST02 SWAPS reported what does that mean.

Hi Team,
In ST02 of one of the system all the apps I see many SWAPS column with value and in red color, what it mean
program, swaps with 11,349
generic key with 68
single record with 1,002
Thanks
Vijay

Hi,
ST02 is the buffer monitor that offers instance specific information that provides:
1. status of different buffers instance wise
2. information on memory usage instance wise
3. information on table buffering at instance level
Swapping takes place for two reasons:
1. not enough 'free space left' in buffer for buffering new objects
2. buffer has run ouf of 'free directory entries' that can be contained in one buffer area *
Directory entries diminish the available size of the buffer, independent of their usage.
Swaps are to be avoided, as are all other situations leading to lines shown in red in the ST02 display.
Please note that Buffer swaps occur when buffer content is deleted from the buffer and is replaced by other content. It has no relation at all to the swapping mechanism on OS level.
An example with a more practical outlook to swapping observed:
Use transactions SM50, ST03N and ST02 to identify the problem.
a. Using SM50 you might find high number of work processes accessing tables related to ABAP sources and status as 'Load Program'. This hints to a problem with Program [PXA] buffer.
b. In transaction ST03N, you find unusually high 'load and generation time' causing even higher wait times. Threshold for load and generation time is typically 50 ms.
c. In buffer monitor i.e. ST02, you find many swaps [typically more than 10000 swaps happening per day for program buffer]. Check on hit ratio [value below 95% is typically poor]. This indicates problem. Program buffer could be small!!
If program buffer is small, it means that workprocesses require to reload program loads over and over again which causes bad system performance.
Resolution: Increase program buffer size/ check on load and generation times/ hit-ratio increases/ system response time also lowers down!! : )
Regards,
Shabnam.

St02 - Swaps in Red( Common but complicated)

Hello Friends,
I am using SAP Netweaver 2004s, SAP_BASIS - 700, OS - Windows NT 6.1, DB- MSSQL 8.00.194.
In Tcode- ST02 i found many red alers while swapping. however many entires have hit ratio of 99% hopefully this can be ignored. please correct me if i am wrong. but 2 entries have less hit ratio the details are given below
Initial records   62.77    12,625     10,894      90.78     5,000      1,076      21.52    3,506       7,430
Initial record buffer IRBD
rsdb/ntab/irbdsize   12000 kB   Size of initial record buffer
rsdb/ntab/entrycount 20000      Max. number / 2 of initial records buffered
Single record   73.95    20,000      4,494      22.63       500        375      75.00   1,033 , 824,053
Single record table buffer TABLP
rtbb/buffer_length 20000 kB   Size of single record table buffer
rtbb/max_tables    500        Max. number of buffered tables
My Question is on what basis i can change this parameters? should i increase or decrease the parameter? how to find out exact digit of the profile parameters?
Thanks,
Shwetha

Hi Shwetha,
The number of swaps you get per day is more relevant than the total number in ST02,
which is the swaps since the last system start.
Double click each line and then click the history button to see how many you get per day
The swap values you have don't seem that large if the machine has been up a few days.
You could try adding more to the single record buffer - perhaps double it.
We have always had a low hit rate in all our systems for the initial record buffer.
I have given up worrying about it.
Tony
Edited by: Tony Morrissey on Jul 8, 2010 1:58 PM

Swapping in ST02 in Initial Record Buffer rsdb/ntab/irbdsize

Hello All,
I've been trying to do some tuning in ST02 and was hoping someone might be able to explain why I am getting such a low hit rate on the Initial Records Buffer, and the high level of swapping, when there appears to be plenty free space and plenty free entries.
Here are the stats I see.
Efficiency
HITRATIO          %        42
HITS                    9,645
REQUESTS               22,790
DB access quality %        42
DB access              13,136
DB access saved         9,645
Reorgs                      0
Size
Allocated        KB     8,750
Available        KB     7,500
Used             KB     1,053
Free             KB     6,447
Directory entries
Available              10,000
Used                    3,801
Free                    6,199
Swaps
Objects swapped         9,335
Frames swapped              0
Resets            Total                       0
Any clues would be much appreciated.
Thanks
Steve

I have the same issue and my parameter settings are currently:
rsdb/ntab/irbdsize - 41500
rsdb/ntab/entrycount 45000
Are there any other suggestions? See below for swap information.
Efficiency        HITRATIO          %        43
                   HITS                   10,243
                   REQUESTS               23,731
                   DB access quality %        43
                   DB access              13,488
                   DB access saved        10,243
                   Reorgs                      0
Size              Allocated        KB    42,906
                   Available        KB    41,500
                   Used             KB     4,717
                   Free             KB    36,783
Directory entries Available              11,250
                   Used                    9,759
                   Free                    1,491
Swaps             Objects swapped         3,728
                   Frames swapped              0
Resets            Total                       0

Reg:Swaps in ST02

Hi Gurus,
I have been seeing lot of swaps occuring in ST02,in one our production servers.
I could see the swaps occuring on CUA buffers in huge volumes
Can any body give me any clue on how to go about it,interms of analysing the swaps and fixing the same
Your help would highly be appriciated
Thanks in advance
Rgds-
Venu

hello
you will find some help here : [Online help about buffers|http://help.sap.com/erp2005_ehp_04/helpdata/EN/c4/3a6e98505211d189550000e829fbbd/frameset.htm]
"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."
This means that you have to increase the size of the buffer to avoid swapping.
To find the relevant parameter (in RZ10) for a specific buffer => transaction ST02, double click on the buffer and then click on the button "Current parameters". Here is/are the parameter(s) to increase (be careful of some parameters ... your system can crash or not restart !)
After saving & activating the profile in RZ10, perform at os level the command (under <sid>adm) : sappfpar check to fix the memory problems.
Hope this will help you

ST02 -Tune summary----Swaps.

Hi Friends,
In ST02 Tune summary i am getting more swaps.As per my knowledge we can restart the sytem and increase the corresponding buffer parameter.I already restarted the system but after 2 dys agin i facing the problem with Swaps .
Can any body help me in this issue.Pls suggest any links why the swaps are appers......
i am mentioning the details of ST02 in our Production system.
Table definition       1,093,239
Field definition          753,873
Initial records            823,693
program                    2,119,857
CUA                        3,049,260
Screen                            101,982
Export/impor                  9,760,830
Regards,
vijay

Vijay,
A couple swaps a day are OK. SAP says anything below 10,000/ day is acceptable. However, I know some people like to have no swaps at all.
Unfortunatly there are no set numbers to put for these parameters. It really depends on your system and environment such as how much memory do you have, programs running on your system, what the users are running, and so on.
This really becomes an art more then a science. My suggestion is to start incresing the paramteres by 10%. If it doesn't seem to be making that much of a difference increase by 20 or 30% if your system can handle it. Keep this up until you are comftorable with the number of swaps you see.
Hope this helps.

Swaps no increased in ST02

Hi Friends,
In our development system Swaps no is very high and it shows RED mark in st02
Table definition =25.213
Field definition = 357.579
Initial records = 62.209
program          = 81.856
CUA              = 12.158
Screen          = 879
please check below attached screen shot for more details
Could you please any one help me how to resolve this issue..
Thanks in Advance
Regards,
Venkat

Hi Lisa,
SWAPs themselves are not an indicator of a performance issue.It's unlikely you can avoid them from happening in production systems. What matters is a quality of buffer tuning and a number of swaps hapenning every day. Let's say you are getting more then 10000 swaps each day for the program buffer. Then you'd need to pay attenation to this buffer and try to find out a way to reduce swaps.
Here is the link to SAP help:
http://help.sap.com/saphelp_erp2005vp/helpdata/en/c4/3a6ecc505211d189550000e829fbbd/content.htm
Regards,
Mike
Message was edited by: Mike Puzankov

Swaps are marked red in ST02

Swaps are banded red in ST02 how to come out of it. It is showing as below:
program                93,28   240.000      1.253       0,54    60.000     54.069      90,12 79.874 258.846
CUA                    98,93    12.000      1.466      14,62     6.000      5.417      90,28       0      593
Screen                 99,07    10.297      2.027      20,08     2.000      1.742      87,10     218    1.465
Calendar              100,00       488        367      76,78       200         50      25,00       0      150
OTR                   100,00     4.096      3.439     100,00     2.000      2.000     100,00       0
                                                                                0
Tables                                                                                0
Generic Key          99,86    51.297      2.005       4,02     5.000        285       5,70      49   35.406
Single record        89,43    18.000      5.092      28,52       500        432      86,40      42   78.837
                                                                                0
Export/import          75,56     8.000        899      12,24     2.000                        23.664
Exp./ Imp. SHM         94,04     4.096      3.248      94,45     2.000      1.999      99,95       0
How do you clear red bands, which memories play the role in this scenario?

You have to increase the parameters. Doubeclick on the red ones, press on "current parameters" and increase the given values using RZ10.
Your parameters, e. g. abap/buffersize are very small.
Markus

How clean export/import (st02) swaps?

Hi
We are facing a big problem in PRD environment, point is, very low PRD time performance and users need to work; checking on ST02 systems shows Buffers "Export/Import" swaps values high ( red ), We were wondering if exists a T/C which help us to clean buffers?
Thanks your help!!!

Hugo, (tu hablas español, si es asi hay un foro en español tambien)
The low performance issue is not just a problem in swaps, remember something, they are cumulative so if your system is up from a long time ago, then is normal that ST02 shows swaps, how high depends on hits to the buffers, how is the hit ratios for the buffers with red swaps?
If you take down SAP and start it again swaps will disappear.
If you are experiencing performance problems then it is better to take a look at the ST03N, there you could see if problems are in DB, Network, Presentation server (PC with SAPGUI), process time, etc and there you can narrow the problem.
Did the server was working right and then turned slow from some time ago? or
did you do an upgrade to ECC 6.0? or
is the problem only during certain hours? or
is only when executing some transactions/jobs?
With more info we can help you more...

ST02 Swaps issue

Hi Folks,
As per daily monotioring in ST02 i am getting swaps.Can any body advice me .Tunning the buffers is one solutiion i know this.but i am facing the problem daily .
My Environmet:
SAP--ECC6
DB-ORACLE-10.2.0.2.0
OS- AIX5.

Hi,
When a buffer has not sufficient free-space or free directories, it has to swap objects out of the buffer in order to load a new object on request. The column Swap shows how many objects have been swapped out since system start-up.
Along with the useful suggestions provided by Raghu, I would do the following analysis to optimize the swaps by keeping in mind that "the performance optimization is an on going process".
1. Analyze the Hit Ratio and Swap Counts of each memory components in ST02. Prepare and Excel Sheet and note down the memory components which are required special attention for the performance of the system
e.g. If your PXA buffer is having more than 95% hit ration, but its showing more than 20000 swaps per day then you need to re-size it to reduce the swaps
2. Analyze the concurrent & active User Access to the SAP System and the workload.
3. Compare the existing Memory parameter and other dependent parameter settings (with respect to SAP system(s), Database and OS) with the recommendation suggested by SAP official Documents (Inst Guide, SAP Notes, etc..).
3. By keeping in mind the available RAM and SWAP Space, step-by-step, Increase the space value of affected Memory components by 10% to 20% of Existing settings.
4. If the System is configured with more work processes of same types and the all are not used at all even during peak workload (of month or of week or of year), then decrease the counts of work processes to reduce the memory usage so that we can optimize other required memory parameters with more space.
5. If the System is having not enough resources to provide better performance due to resource bottlenecks, then One will prefer:
- to upgrade the H/W on existing SAP System host
- to install additional Application Server(s) (on other system with highly equipped H/W resources), to take the advantage of Log-on Load Balancing.
Please refer these SAP Notes:
Note 750205 - High memory usage with AIX5.2/5.3 and Oracle9.2
Note 425207 - SAP memory management, current parameter ranges
Note 830576 - Parameter recommendations for Oracle 10g,
Note 146289 - Parameter Recommendations for 64-Bit SAP Kernel
One more thing we are not taking Offline back up due to business need system continuous available.Please advice me
Perform Consistent Online Backup (Online Backup + Redo Log Backup) and frequent Archive Log Backup.
Regards,
Bhavik G. Shroff

Swaps values showing in RED -TCODE ST02

Hi All,
When I checked the ST02 transaction value of "SWAPS" for program buffer,CUA buffer,screen buffer, Tables generic key buffer and export/import buffer are showing in "RED" colour.
                          (%)           (kb)             %
Buffer               Hitratio      Allocated     Free Space    swaps
Program           99.88         900000        0.36             19541
CUA                99.9           10,000         1.27             37960
export/import    94.33         40,000         29.10          750,676
Swaps value are showing in RED mark....Is there somthing fishy? What can be done to overcome this issue?
Thanks in advance
Regards,
Prashant.

Dear Prashant,
SWAP is the amount of page space available at OS level. In case of windows it should not be more than 4 times the ram and in case of UNIX 3 times the ram. If swap or paging is configured high is the paging rate and low is the performance. If there is no more free directory entries are available in the buffer for new objects, old objects are removed and the space is occupied by new objects thus a swapping takes place i.e some buffer content is removed from the buffer and replaced by new buffer contents. High swap is normally a symptom of memory bottleneck.
Red indicates swaps are to be avoided and indicate that there might be a bottleneck.
What can be done to overcome this issue?
You need to increase the parameter then.
Double-click on the red value, click on "current parameters" and increase that parameter in the instance profile using RZ10. If the parameters are not yet in the profile, add them.
After changing the instance profile you need to restart the instance.
Regards,
Ashutosh

St02 swaps red

Hi all,
When i checked the swaps in st02 it is showing as red.What to do plz.Should i change the parameters.
          Buffer            Hitratio   Allocated         Free space        Dir. size      Free directory         Swaps       Database
                           [%]       [kB]         [kB]         [%]      Entries      Entries       [%]                   accesses
Nametab (NTAB)
Table definition        96.10         7,151            0     0.00        30,000            0     0.00       159,968      385,089
Field description       96.55        32,344        5,702    19.01        30,000       21,404    71.35       254,965      263,737
Short NTAB              99.74         3,438        2,137    85.48         7,500        5,803    77.37             0        1,697
Initial records         96.18         5,438          177     3.93         7,500          654     8.72        96,328      103,175
Program                   93.68       500,000        1,322     0.28       125,000      111,378    89.10       161,705      626,010
CUA                       99.94         8,000        4,836    70.38         4,000        3,475    86.88             0          530
Screen                    99.86        25,391       18,314    72.89         4,500        4,016    89.24             0          516
Calendar                 100.00           488          394    82.08           200           95    47.50             0          105
OTR                      100.00         4,096        3,531   100.00         2,000        2,000   100.00             0            0
Tables
Generic key             99.99        99,023        9,072     9.44        13,000          998     7.68            12       59,612
Single record           97.10       100,000       75,927    76.12         1,000          876    87.60             0      171,530
Export/import             66.42        20,000       11,764    81.85        20,000       18,587    92.94             0            0
Exp./Imp. SHM             16.95         4,096        3,490    98.84         2,000        1,999    99.95             0            0

Hi Ambarish,
These are the values which u can take as reference
rsdb/ntab/entrycount               30000
rsdb/ntab/irbdsize                  4000
rsdb/ntab/sntabsize                 2500
rsdb/cua/buffersize                 5000
sap/bufdir_entries                 10000
   zcsa/table_buffer_area          50000000
zcsa/db_max_buftab                 10000
rtbb/buffer_length                 30000
   rtbb/max_tables                      500
Release 4.0/4.5:
   rsdb/obj/buffersize              4096          (kB)
   rsdb/obj/max_objects            5000          (buffer entries)
   rsdb/obj/large_object_size       8192          (Byte)
As of Release 4.6:
   rsdb/obj/buffersize            20000            (kB)
   rsdb/obj/max_objects            20000
   rsdb/obj/large_object_size       8192          (Byte)
extend the buffers to 30 -40% this may help you
Regards'
Zia

How to reduce Swaps in ST02

Dear Experts,
In Transaction ST02 there are heavy swaps in the following buffers:
Field description
Initial records
Program
CUA
Screen
Tables
Generic key
Single record
Export/import
How to reduce them; If parameters has to be changed Pl let me know the parameters to be changed and also sequence to be followed.
It would really be helpful if you could let me know how to calculate the parameter values, and sequence to be followed as ease.
Details:
OS: HP-UX 11.23
ECC 5.0
Oracle Release 9.2.0.6.0
Physical mem avail Kb 16,764,976
Regards
Injamuri

Hi,
Please click [buffers|http://help.sap.com/erp2005_ehp_04/helpdata/EN/c4/3a6e98505211d189550000e829fbbd/frameset.htm] for information.
For Table Buffer or TABL
zcsa/table_buffer_area u2013 for size of table buffer data area.
zcsa/db_max_buftab u2013 for directory entries u2013 one for every resident table
For Single key table Buffer or TABLEP.
rtbb/max_tables u2013 Directory Entries u2013 One for each table.
rtbb/buffer_length u2013 Size of data area
Program buffer
abap/buffersize u2013 Only parameter. No of directory entries are calculated automatically.
For Screen Buffer or PRES.
zcsa/bufdir_entries u2013 Directory size u2013 One per screen.
zcsa/presentation_buffer_area u2013 Total screen buffer size in KB.
CUA buffers
rsdb/cua/buffersize u2013 total Buffer in KB and no of directories are caluated by dividing the same with 2K.
Role and paging buffer.
rdisp/ROLL_SHM u2013 For role buffer
rdisp/PG_SHM u2013 For paging buffer
Calendar Buffer
zcsa/calendar_area
With Regards,
Krishna.

ST02 SWAPS are more

Hi,
Iam new to db tuning . My system shows more SWAPS when i go to ST02 .
System slow down performanance.SWAPs are showing more.
Any idea how to resolve this.
Thanks
Lisa

Hi Lisa,
          Lars is very correct.There may be some reasons as
    told by Lars.In order to solve this problem u can follow
    these steps.
1)Send a session data to SAP by executing tr code "SDCCN"
    or "SDCC".On the basis of this session data SAP will
    send u a Analyzed Early watch report.
            In which u can check whether some programs are
    being swapped frequently.
                   Another reaSON may be low buffer space.
     For this u can increase the size of buffer.
   You can check programs responce time by urself by using
    Tr code ST03.
Hope this will help you.
Regards
   Aditya Kumar

SWAP - ST02

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