Performance Management

Breaking response time into components, the analysis transactions, buffers and memory, and the right order in which to improve things.

"The system is slow" is among the most frequent complaints Basis receives, and the first task is establishing what exactly is slow.

Components of response time

Where the time goes

Component	Meaning	Suspect if high
Wait time	Waiting for a free work process	Too few processes, long runners
Roll time	Swapping user context	Memory pressure
Load time	Loading programs	Program buffer too small
CPU time	ABAP execution	Inefficient loops, large volumes
Database time	Database access	Missing indexes, poor SQL
Enqueue time	Waiting for locks	Lock contention
GUI time	Screen transfer	Network or GUI settings

The analysis tools

Code	Purpose
ST03 / ST03N	Workload analysis; the starting point
ST05	SQL trace
ST02	Buffer hit rates and swaps
ST06	Operating system CPU, memory and disk
SM50 / SM66	Work process state
SAT	ABAP runtime analysis
DB02	Database space and objects

Reading ST03

Look for transactions that are both frequent and slow. Something taking two seconds five thousand times a day matters more than something taking ten seconds three times.

Buffers

Buffers and target hit rates

Buffer	Content	Target
Program	Compiled ABAP	Above 98%
Generic key	Table data by partial key	Above 95%
Single record	Individual rows	Above 95%
CUA	Menus and screen definitions	Above 98%
Screen	Dynpro definitions	Above 98%

Memory

How memory is consumed

Order	Area	Content
1	Roll area	Used first, per process
2	Extended memory	Shared; the main working area
3	Heap	After extended memory is exhausted; private, causing PRIV mode

What to fix first

SQL: add indexes, remove SELECTs from loops — by far the largest effect
Program logic: eliminate nested loops and unnecessary work
Archiving: reduce table sizes by removing or offloading old data
Buffers and memory: parameter tuning
Hardware: the last resort, and never a root-cause fix