Performance tuning ABAP Production system

[Former Member]

Greetings, we have been advise to increase our SAP buffer area on all our servers by 20% (abap/buffersize) ensuring we have enough physical memory available on the server. I want to make sure I am doing this correctly. We are currently following the SAP Note 88416 - Zero adminstration memory management for ABAP servers. Since we are going to kernel 7.2, what suggestion do you have regarding the physcial memory and/or buffersize?

Please note the following:

SAP ECC EHP4

Window 2008 64 bit

Oracle 10.2.0.4

Kernel 7.2

System Parameters:

abap/buffersize = 400000 (increase 20% to 480,000)

abap/heap_area_dia = 2,000,000,000

abap/heap_area_nondia = 0

abap/heap_area_total = 17,176,723,456

abap/heaplimit  = 40,000,000

PHYS_MEMSIZE - 16,381

em/initial_size_MB: 16,381

em/max_size_MB 100000

ST04

Data buffer: 1,015,808

Logical read: 92,335,673,525

Quality: 96.7%

Physical read: 3,060,128,257

Size default pool (KB): 1,015,808

Physical write: 64,098,659

Buffer busy waits: 18,007,873

Shared pool:

Size (kb): 655,360

Buffer wait time: 54,244

We had a big performance issue ... we usually restart SAP to clear out the buffers but want to make tuning our permit solution...

Thank you in advance.

[AtulKumarJain · Accepted solution]

Hi ,

Please follow the SAP Note 88416 as you mention you have windows server but for pagefile calculation please use  SAP Note No. 1518419

Best Regards,

Atul

[Former Member · Accepted solution]

Can you advise what PHYS_MEMSIZE=20% means from SAP note 88416 ... ?

Is it stating you add 20% to the existing PHYS_MEMSIZE (16,381) or the parameter is 20% of the exisiting PHYS_MEMSIZE (16,381).

Thank you in advance.

[Former Member · Accepted solution]

Hi,

If you have a 7.20 kernel or above, you can set PHYS_MEMSIZE to a percentage of the memory allocated to that machine.  This does not mean you have to set it to 20%, you could choose 50%.  If you have the DB instance also running on this server (or virtual server) this should not be set to 100% of the RAM, more likely 50%.

[Former Member]

Hi,

Looking at a couple of easy ones first:

1. You have 16GB RAM, so increase your program buffer to 1GB minimum.

2. Check ST02 and ensure that the Table Definition, Field Definition, and Short NTAB are large enough so that the HitRatio is above 99%.

3. CUA should have few swaps - increase it if needed.

4. Assuming the DB is on the same server as the Application, then PhysMemSize needs to exclude the DB buffer area. 

There's a start, but you need a Basis consultant in to really help on the ground.  And restarting the server flushes all the buffers, so isn't a good idea.  You really need to find out what the problem is as Roman N says above.

Regards,

Graham

[Former Member]

Graham, please find the hit ratios for the system:

Table definition : 99.37 %

Field definition : 94.42 % (below 99%)

Short NTAB :    99.92 %

Once we make the increase to the buffer to 1 GB ... these numbers should remain above 99% .

[Former Member]

Margie,

No, increasing the program buffer will reduce program buffer swaps.

You also need to increase the Field Definition buffer - that's by a different parameter.  Double click on the Field Definition line and it will give you more information including the parameter name.

I re-iterate, if you have performance issues then you need to get Basis expertise in to help diagnose the issues.

Regards,

Graham.

[Former Member]

We had a big performance issue ... we usually restart SAP to clear out the buffers but want to make tuning our permit solution...

To improve performance you need to make a deep investigation to find all bottlenecks in your system. Only after make required modifications. In process of performance tuning you need to consider the SAP system as a whole containing many components (e.g. SAP buffers, DB layer etc.). settings change for a single component can have a negative effect on the performance as a whole.