SWAPS ST02

[Emy15]

Hello team,

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

Please find below a screen shot for swaps in Tune Summary and give the suggestion...

thanks in advance

[Dino_Pettinaro]

Hi

Could you please show us the actual Parameter set for following Parameters:

Catalog Buffer
rsdb/cua_buffer_size
rsdb/obj/buffersize

Program Buffer
abap/buffersize

Screen Buffer
rsdb/ntab/entrycount

Memory
em/initial_size_MB

Roll & Heap control
ztta/roll_extension
(If too low → heap explosion → swap risk)

abap/heap_area_dia
abap/heap_area_nondia
(Limits heap per work process
Too high = OS pressure
Too low = ABAP dumps)

Rgds
Dino

[Emy15]

Catalog Buffer rsdb/cua_buffer_size = 3000 rsdb/obj/buffersize = 160317 Program Buffer abap/buffersize = Screen Buffer rsdb/ntab/entrycount = 2568192 Memory em/initial_size_MB = 12525 Roll & Heap control ztta/roll_extension = 4000000000 abap/heap_area_dia = 2000000000 abap/heap_area_nondia = 2000000000

[Emy15]

rsdb/cua_buffer_size = 3000 rsdb/obj/buffersize = 160317

[Emy15]

abap/buffersize = 2568192

[Emy15]

rsdb/ntab/entrycount = 2568192

[Emy15]

em/initial_size_MB = 12525

[Emy15]

ztta/roll_extension = 4000000000

[Emy15]

abap/heap_area_dia = 2000000000 abap/heap_area_nondia = 2000000000

[Dino_Pettinaro]

Based on the current configuration and observed swap statistics, I would recommend the following optimization steps:

Increase Extended Memory
Parameter:

em/initial_size_MB

Current value:

12525

Recommended value:

18000 – 24000

Please ensure sufficient physical RAM is available on the operating system before increasing this parameter.

This adjustment is considered the most important optimization step, as insufficient Extended Memory can force work processes into Heap memory usage, potentially leading to OS swap pressure and ST02 buffer swaps.

Reduce excessive Heap allocation
Parameter:

abap/heap_area_dia

Current value:

2000000000

Recommended value:

1000000000

Reason:

Prevent excessive DIA work process memory consumption
Prioritize Extended Memory usage
Reduce operating system memory pressure
Improve overall memory stability

Increase Program Buffer
Parameter:

abap/buffersize

Current value:

2568192

Recommended value:

3500000 – 4500000

This can help reduce program reloads and buffer swaps, especially in systems with extensive custom developments or high workload activity.

Increase Catalog Buffer
Parameter:

rsdb/obj/buffersize

Current value:

160317

Recommended value:

250000 – 350000

This adjustment is particularly recommended due to the high Catalog Buffer swap statistics observed in ST02.

After implementing the changes, the SAP instance should be restarted and monitored for at least 24–48 hours.

Very Important Next Check

You MUST check OS memory.

In ST06 or Linux:

free -g
vmstat 1
top

Especially check:

• swap used
• free RAM
• paging activity

Because:

If OS swap is already active,
increasing buffers may worsen the situation.