abap performance

[Former Member]

how to do performance tunning of a program

[RichHeilman]

There are a couple things that you can do to help with performance, but the most important is to make sure that your SELECT statements are optimized. You can check the performance using SQL trace, transaction ST05

Regards,

Rich Heilman

[Former Member]

Use runtime analysis/performance analysis using SE30 and ST05 transaction codes. This will give you an idea of processing times and you can fine tune your program accordingly.

Cheers

[anversha_s]

HI,

http://www.erpgenie.com/abap/performance.htm

http://www.thespot4sap.com/Articles/SAPABAPPerformanceTuning_PerformanceAnalysisTools.asp

http://www.sap-img.com/abap/performance-tuning-for-data-selection-statement.htm

Performance tuning for Data Selection Statement

For all entries

The for all entries creates a where clause, where all the entries in the driver table are combined with OR. If the number of

entries in the driver table is larger than rsdb/max_blocking_factor, several similar SQL statements are executed to limit the

length of the WHERE clause.

The plus

Large amount of data

Mixing processing and reading of data

Fast internal reprocessing of data

Fast

The Minus

Difficult to program/understand

Memory could be critical (use FREE or PACKAGE size)

Some steps that might make FOR ALL ENTRIES more efficient:

Removing duplicates from the the driver table

Sorting the driver table

If possible, convert the data in the driver table to ranges so a BETWEEN statement is used instead of and OR statement:

FOR ALL ENTRIES IN i_tab

WHERE mykey >= i_tab-low and

mykey <= i_tab-high.

Nested selects

The plus:

Small amount of data

Mixing processing and reading of data

Easy to code - and understand

The minus:

Large amount of data

when mixed processing isn’t needed

Performance killer no. 1

Select using JOINS

The plus

Very large amount of data

Similar to Nested selects - when the accesses are planned by the programmer

In some cases the fastest

Not so memory critical

The minus

Very difficult to program/understand

Mixing processing and reading of data not possible

Use the selection criteria

SELECT * FROM SBOOK.                    
  CHECK: SBOOK-CARRID = 'LH' AND        
                  SBOOK-CONNID = '0400'.         
ENDSELECT.                              
SELECT * FROM SBOOK                      
  WHERE CARRID = 'LH' AND                
        CONNID = '0400'.                 
ENDSELECT.                               
Use the aggregated functions 
C4A = '000'.               
SELECT * FROM T100         
  WHERE SPRSL = 'D' AND    
        ARBGB = '00'.      
  CHECK: T100-MSGNR > C4A. 
  C4A = T100-MSGNR.        
ENDSELECT.                 

SELECT MAX( MSGNR ) FROM T100 INTO C4A  
 WHERE SPRSL = 'D' AND                 
       ARBGB = '00'.                   
Select with view
SELECT * FROM DD01L                     
  WHERE DOMNAME LIKE 'CHAR%'            
        AND AS4LOCAL = 'A'.             
  SELECT SINGLE * FROM DD01T            
    WHERE   DOMNAME    = DD01L-DOMNAME  
        AND AS4LOCAL   = 'A'            
        AND AS4VERS    = DD01L-AS4VERS  
        AND DDLANGUAGE = SY-LANGU.      
ENDSELECT.                              

SELECT * FROM DD01V                     
 WHERE DOMNAME LIKE 'CHAR%'            
       AND DDLANGUAGE = SY-LANGU.      
ENDSELECT.                              
Select with index support
SELECT * FROM T100             
 WHERE     ARBGB = '00'       
       AND MSGNR = '999'.     
ENDSELECT.                     

SELECT * FROM T002.              
  SELECT * FROM T100             
    WHERE     SPRSL = T002-SPRAS 
          AND ARBGB = '00'       
          AND MSGNR = '999'.     
  ENDSELECT.                     
ENDSELECT.                       


Select … Into table
REFRESH X006.                  
SELECT * FROM T006 INTO X006.  
  APPEND X006.                 
ENDSELECT

SELECT * FROM T006 INTO TABLE X006.


Select with selection list
SELECT * FROM DD01L               
  WHERE DOMNAME LIKE 'CHAR%'      
        AND AS4LOCAL = 'A'.       
ENDSELECT

SELECT DOMNAME FROM DD01L     
 INTO DD01L-DOMNAME          
 WHERE DOMNAME LIKE 'CHAR%'  
       AND AS4LOCAL = 'A'.   
ENDSELECT
Key access to multiple lines
LOOP AT TAB.           
 CHECK TAB-K = KVAL.  
 " ...                
ENDLOOP.               

LOOP AT TAB WHERE K = KVAL.      
  " ...                          
ENDLOOP.

Copying internal tables

REFRESH TAB_DEST.               
LOOP AT TAB_SRC INTO TAB_DEST.  
  APPEND TAB_DEST.              
ENDLOOP.                        

TAB_DEST[] = TAB_SRC[].
Modifying a set of lines
LOOP AT TAB.              
  IF TAB-FLAG IS INITIAL. 
    TAB-FLAG = 'X'.       
  ENDIF.                  
  MODIFY TAB.             
ENDLOOP.                  

TAB-FLAG = 'X'.                   
MODIFY TAB TRANSPORTING FLAG      
           WHERE FLAG IS INITIAL. 
Deleting a sequence of lines
DO 101 TIMES.                
  DELETE TAB_DEST INDEX 450. 
ENDDO.                       

DELETE TAB_DEST FROM 450 TO 550.


Linear search vs. binary
READ TABLE TAB WITH KEY K = 'X'.

READ TABLE TAB WITH KEY K = 'X' BINARY SEARCH.
Comparison of internal tables
DESCRIBE TABLE: TAB1 LINES L1,       
                TAB2 LINES L2.       
                                     
IF L1 <> L2.                         
  TAB_DIFFERENT = 'X'.               
ELSE.                                
  TAB_DIFFERENT = SPACE.             
  LOOP AT TAB1.                      
    READ TABLE TAB2 INDEX SY-TABIX.  
    IF TAB1 <> TAB2.                 
      TAB_DIFFERENT = 'X'. EXIT.     
    ENDIF.                           
  ENDLOOP.                           
ENDIF.                               
                                     
IF TAB_DIFFERENT = SPACE.            
  " ...                              
ENDIF.                               

IF TAB1[] = TAB2[].   
 " ...               
ENDIF.                
Modify selected components
LOOP AT TAB.            
 TAB-DATE = SY-DATUM.  
 MODIFY TAB.           
ENDLOOP.                

WA-DATE = SY-DATUM.                     
LOOP AT TAB.                            
 MODIFY TAB FROM WA TRANSPORTING DATE. 
ENDLOOP.                                
Appending two internal tables
LOOP AT TAB_SRC.               
  APPEND TAB_SRC TO TAB_DEST.  
ENDLOOP

APPEND LINES OF TAB_SRC TO TAB_DEST.
Deleting a set of lines
LOOP AT TAB_DEST WHERE K = KVAL.  
  DELETE TAB_DEST.                
ENDLOOP

DELETE TAB_DEST WHERE K = KVAL.

Tools available in SAP to pin-point a performance problem

The runtime analysis (SE30)

SQL Trace (ST05)

Tips and Tricks tool

The performance database

Optimizing the load of the database

Using table buffering

Using buffered tables improves the performance considerably. Note that in some cases a stament can not be used with a buffered table, so when using these staments the buffer will be bypassed. These staments are:

Select DISTINCT

ORDER BY / GROUP BY / HAVING clause

Any WHERE clasuse that contains a subquery or IS NULL expression

JOIN s

A SELECT... FOR UPDATE

If you wnat to explicitly bypass the bufer, use the BYPASS BUFFER addition to the SELECT clause.

Use the ABAP SORT Clause Instead of ORDER BY

The ORDER BY clause is executed on the database server while the ABAP SORT statement is executed on the application server. The datbase server will usually be the bottleneck, so sometimes it is better to move thje sort from the datsbase server to the application server.

If you are not sorting by the primary key ( E.g. using the ORDER BY PRIMARY key statement) but are sorting by another key, it could be better to use the ABAP SORT stament to sort the data in an internal table. Note however that for very large result sets it might not be a feasible solution and you would want to let the datbase server sort it.

Avoid ther SELECT DISTINCT Statement

As with the ORDER BY clause it could be better to avoid using SELECT DISTINCT, if some of the fields are not part of an index. Instead use ABAP SORT + DELETE ADJACENT DUPLICATES on an internal table, to delete duplciate rows.

Regards

Anver

<b>pls mark points to all helpful answers</b>

Message was edited by: Anversha s