SAP Performance & Tuning

An R/3 work process allocates around 5 MB of memory.

The R/3 table buffers allocate approximately 120 MB (40 MB for single record buffers, 80 MB for generic table buffers).

The data buffers of the database use around 500 MB of memory. The database on the disks can reach a size of several terabytes.

The data transfer between front end and application server occurs in blocks of 2 KB.

The transfer between application server and database server occurs in blocks of up to 32 KB.

Memory Allocation in SAP

Work process

WP WP WP WPRoll area

Work Process

To DB server

Dispatcher Dispatcher Queue

From presentation server

Application server

Response time:

Time from the receipt of a user request to the sending of a response ( measured on the application

server; does not include network time between the presentation server and the application server).

Dispatcher wait time: Time spent by the user request in the dispatcher queue.

Roll-in: Time required to roll the user context in to the R/3 work process.

Load time: Time required for loading and generating R/3 Repository or ABAP Dictionary objects.

Processing time: = response time - dispatcher wait time - roll-in - roll-out - load time - database

time enqueue time - roll wait time

Enqueue time:

Time from sending an enqueue request to the R/3 enqueue server to the receipt of the results

General Definitions

Database time: Time from sending an SQL statement to the receipt of the results (measured on

the application server; includes network time between the application server and the database

server).

Roll wait time: Time in which the user context is rolled out of the work process pending response

to an RFC call.

 

Roll-out: Time required to roll the user context in to the roll buffer.

CPU time: Time spent by the CPU in processing the transaction step (measured by the operating

system; not an additive component of the response time).

Definitions

Work Load Monitor

ST03 -> Performance Data base (Work Load Monitor )

Select Server , Time .

If DB response > 600 ms then there is fundamental problem with R3 / DB .

Initial Check’s to be done to measure Performance

ST 03

DB 01

SM 50

SM50 ( Snap Shot analysis )

To identify performance critical objects .

To identify long running objects

How to identify long running process ?

Refresh the screen continuously , If a work process is there

for a long time then it is long running process

Important fields to know about the action to be done : Action / Table

Snap Shot Analysis

Check R3 based WP overview from ( SM50 )

Find long running WP and note its Action / Table field

Find Action ( Sequential / Direct / Insert )

Call DB Monitor ( DB01)

Check if any lock is there . If so find the user who is responsible and Tryto remove the lock , Or delete the lock .

Then based on the analysis go for SQL Trace / ABAP Run time analysis

General Flow to get into tuning process

Select Proper internal table types

Standard Tables :

Used generally . Can be sorted

Sorted Tables

Sorted automatically based on key

Hashed Tables

Used when I record is to be retreived . Good in performance . Work based on hash

Key

Initial Reporting consideration

Se38 ->ABAP Debugger -> Settings ->Memory Display On Debugger Finding Memory

SE30 (Runtime Analysis)

The runtime analysis is an additional development workbench tool that is quite useful for

analyzing performance of an ABAP / 4 Program or transaction. With this tool, the system can

display information about:

Executed instruction

Accessed execution time.

Tables and Types of access.

Chronological execution flow

ST05 (SQL Trace)

he SQL trace is a tool, which allows displaying and analyzing the contents for the database

calls, which are made by the reports and transactions written in ABAP/4. It monitors

programs and transactions on the database level. With the help of this facility for every open

SQL instructions, you can display, about which SQL Embedded (DECLARE, OPEN,

FETCH) Statement have been executed, besides analyzing the system performance.

SLIN or PROGRAM -> CHECK -> EXTENDED PROGRAM CHECK

ST03, ST02, ST04 are the tcode for workload, tuning and DB Performance Monitoring

codes.

ST 05 ->SQL Trace -> Activate Trace

Go back to SE 38 .

Then Run The program from SE38 ,

Now again Come back to ST05 ,

Deactivate trace .

Now press Display Trace .

SQL Trace

SQL Trace

Buffer Trace

Enquee Trace

RFC Trace

ST05 Components

SQL Trace Internal Mechanism

The goal of using an SQL Performance Trace is to find SQL statements with a high optimization potential. Use three user sessions.

One user session is for the trace list, one for the compressed summary, and one for identical selects.

From the trace list you can access Explain SQL or the ABAP code. An expensive SQL statement is indicated when a database operation takes longer

than 200,000 milliseconds, or when more than 10 FETCHes are required for a database operation.

  In addition, a series of SQL statements that are similar in structure usually indicate nesting that can be optimized considerably. If the sum of SQL statements that are similar in structure take more than 200,000 milliseconds, they can be regarded as expensive.

SQL Trace Goals

SE30 -> Give Report name and Execute , Then click Analyze ,You will get DB time and ABAP run time

Run Time analysis

Run Time Analysis ( SE 30 )

Runtime analysis ( Comparing more 2 programs )

Very effective measure to increase performance in Select queries

REPORT ZPR_PER_T1

TABLES : VBAK .

Data Begin of itab occurs 0 Include structure vbak data end of ITAB.

Select * from vbak into table itab .

Read table itab with key vbeln = '400151' .

REPORT ZPR_PER_T1 TABLES : VBAK .

Data Begin of itab occurs 0 . Include structure vbak .data end of ITAB.

Select * from vbak into table itab .

Read table itab with key vbeln = '400151' BINARY SEARCH.

Binary Search

First see runtime analysis ( SE30 ), try to make 50% of ABAP time and Database time.

Next SQL Trace (ST05), check which table is taking more time and try to minimize it by using full key or creating index for the where clause.

Next see logic in the program, try to avoid multiple reads on same table and try to minimize unnecessary data

Next try to remove for all entries if it has large amount of data in the for all entries internal table.

Next try to read Header table first than item table.

Next try to put joins

Next try to remove nested select's.

Steps to Improve Performance

Select field in sequence as defined in database

free intrenal table memory wnen table is not required for further processing.

Steps to Improve Performance

Comparison of select statements

Not Recommended REFRESH TAB_DEST.                LOOP AT TAB_SRC INTO

TAB_DEST.  APPEND TAB_DEST.              ENDLOOP

Recommended

TAB_DEST[ ] = TAB_SRC[ ].

Some changes to statements to improve performance

Use already provided aggregate functions instead of manually coding it in ABAP.

Not Recommended

Maxnu = 0. Select * from zflight where airln =

‘LF’ and cntry = ‘IN’.

Check zflight-fligh > maxnu.

Maxnu = zflight-fligh.

Endselect.

       

  Recommended

Select max( fligh ) from zflight intmaxnu where airln = ‘LF’ and cntry

= ‘IN’.

Similary use MIN, AVG,COUNT,and SUM as needed.

Aggregate Function

Not Recommended

Refresh: itab_flight.

Select * from zflight into intab_flight.

Append intab_flight.

Clear intab_flight.

Endselect.

        

Recommended

Refresh: intab_flight.

Select * from zflight into table intab_flight

Avoid append statement

Not Recommended

Loop at int_fligh.

If int_fligh-flag is initial.

Int_fligh-flag = ‘X’.

Endif.

Modify int_fligh.

Endloop.

    

     Recommended

Int_fligh-flag = ‘X’.

Modify int_fligh transporting flag where flag is initial.

Modifying lines of internal table

1. Avoid using SELECT...ENDSELECT... construct and use SELECT ... INTO TABLE.

2. Use WHERE clause in your SELECT statement to restrict the volume of data retrieved.

3. Design your Query to Use as much index fields as possible from left to right in your WHERE statement

4. Either enable buffering in your database table or create Indexes to speed up the query.

5. Use FOR ALL ENTRIES in your SELECT statement to retrieve the matching records at one shot.

How to improve Performance

6. Avoid using nested SELECT statement, SELECT within LOOPs.

7. Avoid using INTO CORRESPONDING FIELDS OF TABLE. Instead use INTO TABLE.

8. Avoid using SELECT * and Select only the required fields from the table.

9. Avoid nested loops when working with large internal tables.

10. Use assign instead of into in LOOPs for table types with large work areas

How to improve Performance

11. When in doubt call transaction SE30 and use the examples and check your code

12. Whenever using READ TABLE use BINARY SEARCH addition to speed up the search. Be sure to sort the internal table before binary search.

13. Use "CHECK" instead of IF/ENDIF whenever possible.

14. Use "CASE" instead of IF/ENDIF whenever possible.

15. Use "MOVE" with individual variable/field moves instead of "MOVE-CORRESPONDING", creates more coding but is more effcient.

How to improve Performance

SM51 – App. Servers Overview

STAT – Display Statistical Records

ST05 – SQL Trace

SE30 – Runtime Analysis

ST03 – Analysis of Workload

DB02 – Database Performance : Tables and Indexes.

DB05 – Analysis of Table w.r.t. Indexed Fields

ST04 – Database Performance Analysis : Oracle View

SM66 – Global Work Process Overview (Over All App Servers)

SM50 – Process Overview

Some useful Transactions related to performance analysis