1 Introduction
1.1 Purpose of this document
This document is a guideline process that, where possible,
should be followed when reviewing SAP system performance and
tuning.
This document assumes knowledge of the BASIS module within SAP
environments.
1.2 Process scope
This process covers the process of reviewing system performance
and where applicable identifying issues, problems or bottlenecks
that can or will lead to poor system performance. This document can
also be used to help identify the cause of poor system
performance.
1.3 Brief Summary of Process Benefits
A SAP R/3 system is an online transactional processing (OLTP)
system. Good system performance is essential to the business and
users to get the most out of the system. Regular proactive checks
on system performance will help to identify any potential issues
and ensure good system performance is available to those users.
SAP R/3 SYSTEM PERFORMANCE CHECK
2.1 SM50 Process Overview
SM50 is also a snapshot view of current activities but specific
to the instance you are logged onto.This shows all work processes
configured for the instance.
Check that there are free DIA work processes
If all DIA work processes are in constant use this will lead to
high wait time and SAP will hang.
2.2 ST03 Workload Monitor
Important for detailed analysis: Change to Expert Mode
If a problem is detected, the data in the workload monitor can
be used as follows to identify the area of the system where the
problem is located.
First check for general performance problems affecting all
transactions. Good general performance is normally indicated
by:
Wait time < 10% response time
Average roll-in time < 20ms
Average roll wait time < 200ms
Average load (and generation ) time < 10% of response time
(< 50ms)
Average database request time < 40% of (response time wait
time)
Average CPU time < 40% of (response time wait time)
Average CPU time not much than processing time
Average Dialog response time Depends on customer requirements
there is no general rule but below 2 seconds is expected. Analysis
Roadmap: Using the Workload Monitor
Wait time > 10% of response time?
General performance problem?
High Database time > 40% of response time?
Detailed analysis of the database Processing time > CPU time
x 2?
Detailed analysis of hardware bottlenecks
Load time > 50 ms?
Detailed analysis of R/3 memory configuration (Is the program
buffer too small?)
Roll wait time or GUI time > 200 ms?
Detailed analysis of interfaces and GUI communication.
From detailed analysis > last minutes load > transaction
profile enables you to find out the most used transactions and the
average response time for these transactions. Tuning these
transactions creates the greatest improvement in overall
performance.
Analysis Roadmap: Using the Transaction Profile
Transaction profile sorted by Response time total
Programs with high CPU time: CPU time >40% of response
time
Detailed analysis with ABAP Trace
Programs with high database time: database time > 40% of
response time
Detailed analysis of SQL statements with SQL Trace
Programs with high GUI times (> 200ms)
Network Check
2.4 ST06 Operating System MonitorIf it is OS sideCheck whether
both R3 and DB on same host.
Windows: Check the task manager for utilized memory/CPU
usage
Linux/Unix: Check the top command for memory, CPU
utilization..Important Statistics displayed in the Operating System
Monitor include:
CPU load averages and % CPU utilisation
Operating system swapping and % memory utilisation
% disk utilisation
Operating system configuration parameters
CPU Bottlenecks are indicated during several snapshots by:
Idle CPU 97%
Few buffer swaps < 5000 per day
Some free space in buffer but not too much
Reasons for program buffer swaps could be that the program
buffer is sized too small. This will lead to programs are swapped
out, and the reload causes high load and long database request
times. The solution is to increase the program buffer size.
The lower part of ST02 displays data on extended memory size and
usage.
No heap memory should be in use, this will lead to performance
problems as physical memory is exhausted and SAP will be paging
into operating system swap.
Memory utilization (Extended memory) Current use, Execute
immediately.
5. Run the report in se38: RSBTCCNS to clear the in
consistencies for background jobs.
6. Run the report in se38: RSTS0043 to clear the logs: spool,
background job logs.
7. Do spool consistency check in SP12 ->TemSe Data Storage
-> consistency check.