Objects in SAP buffers

[Former Member]

Hi,

Everyday, a function module is called on demand within a program. This is a standard function module. The problem is that everyday, the first call of the function module has a very long runtime. The next executions of the function module could take 8 to 10 time less runtime. This behavior has been also checked in se37.

With the developper, we executed a runtime analysis (se30) and compared the result of the first call (about 8 secondes) to the next 5 call (about 1 seconde each). We didn't find any clue on the cause of this behavior.

We tried to run another standard function module with se37, same behavior. A very long runtime during the first call, and very small runtime after then.

My opinion is that it is a buffer management issue. I checked on db13, everynight runs the job "update statistics". In st02, hit ratio for program buffer, roll and paging are good, there are little swap but not so much daily swap.

I have no idea how to improve the first execution or how to solve this issue. Hope some expert could help me with this.

Thanks in advance for your answers.

Kind regards,

Clément

[Former Member]

Everyday, a function module is called on demand within a program. This is a standard function module. The problem is that everyday, the first call of the function module has a very long runtime. The next executions of the function module could take 8 to 10 time less runtime. This behavior has been also checked in se37.

Every day? So it is resetting every day. Just in case, is it possible that there is an offline backup of the system every night? 

It has always behave this way since the BAPI which call the function module was implemented.

BAPI is involved --> I took it as a custom/Y/Z program called a BAPI function since you can measure it using SE30. Could it be possible it is the custom program behaviour caused the time difference? Maybe it keep log and flag to refresh its own buffer(possibly Z table) once a day? and reused it for a whole day before recreate them again next day?

[Former Member]

Hi Henry,

- No daily offline backup.

- The problem occurs when the standard function module is called. This function module is in standard bapi BAPI_OUTB_DELIVERY_CREATENOREF which is itself called in a Z program.

I do not think there is a buffer refresh in that program, i don't even know if it's possible to trace it... My only knowledge concerning buffers as a basis is ST02 and there is no daily reset of buffers according to ST02.

But you're right, I also think it is a buffer issue. Juan advised me to adjust the buffer size.

Thanks for your help.

KR,

Clément

[Former Member]

is this a new system u have installed. from how long it is showing this behaviuour? is there any change in system after which system shows some behaviour any support pack or any thing? regards, Meenakshi

[Former Member]

Hi Meenakshi,

It has always behave this way since the BAPI which call the function module was implemented.

Kind Regards,

Clément

[Former Member]

The customer want to observe the changes on a longer period. I assume it is ok with advices from Juan and mho for the moment. I will update the ticket when the customer will confirm the problem disappeared.

Kind regards,

Clément

[Former Member]

Also increase the space and directory entries for initial records and CUA. Those have a really high miss rate.

Don't get to nervous about the red fields alone, always consider the hit ratio. You can try to start the funtion module in modus one and constantly refresh ST02 in modus two and check if swaps increases during those 8 seconds.

Cheers Michael

[Former Member]

Also thank you Micheal for your advises.

[JPReyes]

Whats your system release and OS/DB versions?... I can see that your bufferes are all over the place... just by checking the program buffer i can tell you that 300.000 is far too small.

Regards, Juan

[Former Member]

Hi Juan,

Thank you for your kick answer.

OS is windows server 2008 R2 and database Oracle 11g.

As we are not in charge of the administration, we will have to ask person in charge to make change. We will increase abap/buffersize to 800.000. We will then check until next friday how the function module call behave.

I give you a feed back at the end of the week.

Kind regards,

Clément

[JPReyes]

Don't focus only on the program buffer, you need to review all your buffers and raise them accordingly, but certainly your buffers in general need some look after, also make sure your DB has the latest SBP (SAP Bundle Patches) and make sure your memory parameters are well optimized.

Regards, Juan

[Former Member]

Does something like it will help ? 😃

ST04 -> Performance -> Statistical Information -> SGA Monitor -> Cache advisory stat. -> Size of estimation

hu... does not exist anymore on a ECC6... [edit] Non Oracle database does not have this tool [/edit]