Re: RE: perfomence of abap program

Former Member · ‎2008 Apr 18

hi guys,

i need some information about perfomence means how to avoid the performe in abap program,my program

takes lot of time to execution may be i think because of SQL statements,now how to reduce the time please guide this its very argent

Former Member · ‎2008 Apr 18

Hi,

Use the Tcode SE30 and press the button tips and tricks. Then it will help u that documnetation.

Please reward points if helpful

Thanks,

suma.

harikrishnan_m · ‎2008 Apr 18

Hi,

1. Try to avoid SELECT stmts inside LOOP..sorry not 'try' Dont use it..u can avoid it by using FOR ALL ENTRIES

2. Try to avoid no of select queries by using JOIN's if say u need to get data from 3 tables wherein each table is linked....

3. Try to modify the internal table using field-symbols...Try to avoid MODIFY stmt for internal table unless unique key is defined for internal table...

4. If u r updating DB table try to update it from an internal table if u have chunk of records,,never try to insert one by one...this way u can reduce no of DB hits...

5. In declaration try to define variables and constants refering data dictionary elements...wht i mean is say u defining

V_MTART(4) TYPE C...here u r actually referring to material type of a material..instead of this u can put it like this

V_MTART type MARA-MTART.

Increases clarity while comparing or doing some operation..

As of now i getting only these things...if i remebr more i will let u know tht....

Rewards if found useful

Regards,

ABAPer 007

Former Member · ‎2008 Apr 18

hi

u can use sql trace

t code ST O5

for checking the performance of ur code (sql query based).

u can also use SE30 -run time analysis.

CODE INSPECTOR-SCI

TCODE - SLIN

cheers

sharad

Edited by: sharad narayan on Apr 18, 2008 12:37 PM

Former Member · ‎2008 Apr 18

hi

The key to reduce base hits is to minimize the number of selects from the data base .just select only what is required and give as many where condition as possible.try to avoid select * statements..Please follow below doc for further details.

SAP ABAP Performance Tuning

Tips & Tricks

Introduction

Need for performance tuning

In this world of SAP programming, ABAP is the universal language. In most of the projects, the focus is on getting a team of ABAP programmers as soon as possible, handing over the technical specifications to them and asking them to churn out the ABAP programs within the “given deadlines”.

Often due to this pressure of schedules and deliveries, the main focus of making a efficient program takes a back seat. An efficient ABAP program is one which delivers the required output to the user in a finite time as per the complexity of the program, rather than hearing the comment “I put the program to run, have my lunch and come back to check the results”.

Leaving aside the hyperbole, a performance optimized ABAP program saves the time of the end user, thus increasing the productivity of the user, and in turn keeping the user and the management happy.

This tutorial focuses on presenting various performance tuning tips and tricks to make the ABAP programs efficient in doing their work. This tutorial also assumes that the reader is well versed in all the concepts and syntax of ABAP programming.

NOTE: Performance of a program is also often limited due to hardware restrictions, which is out of the scope of this article.

============================================================================

Use of selection criteria

Instead of selecting all the data and doing the processing during the selection, it is advisable to restrict the data to the selection criteria itself, rather than filtering it out using the ABAP code.

Not recommended

Select * from zflight.

Check : zflight-airln = ‘LF’ and zflight-fligh = ‘BW222’.

Endselect.

Recommended

Select * from zflight where airln = ‘LF’ and fligh = ‘222’.

Endselect.

One more point to be noted here is of the select *. Often this is a lazy coding practice. When a programmer gives select * even if one or two fields are to be selected, this can significantly slow the program and put unnecessary load on the entire system. When the application server sends this request to the database server, and the database server has to pass on the entire structure for each row back to the application server. This consumes both CPU and networking resources, especially for large structures.

Thus it is advisable to select only those fields that are needed, so that the database server passes only a small amount of data back.

Also it is advisable to avoid selecting the data fields into local variables as this also puts unnecessary load on the server. Instead attempt must be made to select the fields into an internal table.

============================================================================

Use of aggregate functions

Use the already provided aggregate functions, instead of finding out the minimum/maximum values using ABAP code.

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 into maxnu where airln = ‘LF’ and cntry = ‘IN’.

The other aggregate functions that can be used are min (to find the minimum value), avg (to find the average of a Data interval), sum (to add up a data interval) and count (counting the lines in a data selection).

============================================================================

Use of Views instead of base tables

Many times ABAP programmers deal with base tables and nested selects. Instead it is always advisable to see whether there is any view provided by SAP on those base tables, so that the data can be filtered out directly, rather than specially coding for it.

Not recommended

Select * from zcntry where cntry like ‘IN%’.

Select single * from zflight where cntry = zcntry-cntry and airln = ‘LF’.

Endselect.

Recommended

Select * from zcnfl where cntry like ‘IN%’ and airln = ‘LF’.

Endselect.

============================================================================

Use of the into table clause of select statement

Instead of appending one record at a time into an internal table, it is advisable to select all the records in a single shot.

Not recommended

Refresh: int_fligh.

Select * from zflight into int_fligh.

Append int_fligh. Clear int_fligh.

Endselect.

Recommended

Refresh: int_fligh.

Select * from zflight into table int_fligh.

============================================================================

Modifying a group of lines of an internal table

Use the variations of the modify command to speed up this kind of processing.

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.

============================================================================

Use of binary search option

When a programmer uses the read command, the table is sequentially searched. This slows down the processing. Instead of this, use the binary search addition. The binary search algorithm helps faster search of a value in an internal table. It is advisable to sort the internal table before doing a binary search. Binary search repeatedly divides the search interval in half. If the value to be searched is less than the item in the middle of the interval, the search is narrowed to the lower half, otherwise the search is narrowed to the upper half.

Not Recommended

Read table int_fligh with key airln = ‘LF’.

Recommended

Read table int_fligh with key airln = ‘LF’ binary search.

============================================================================

Appending 2 internal tables

Instead of using the normal loop-endloop approach for this kind of programming, use the variation of the append command. Care should be taken that the definition of both the internal tables should be identical.

Not Recommended

Loop at int_fligh1.

Append int_fligh1 to int_fligh2.

Endloop.

Recommended

Append lines of int_fligh1 to int_fligh2.

============================================================================

Using table buffering

Use of buffered tables is recommended to improve the performance considerably. The buffer is bypassed while using the following statements

1. Select distinct

2. Select … for update

3. Order by, group by, having clause

4. Joins

Use the Bypass buffer addition to the select clause in order to explicitly bypass the buffer while selecting the data.

============================================================================

Use of FOR ALL Entries

Outer join can be created using this addition to the where clause in a select statement. It speeds up the performance tremendously, but the cons of using this variation are listed below

1. Duplicates are automatically removed from the resulting data set. Hence care should be taken that the unique key of the detail line items should be given in the select statement.

2. If the table on which the For All Entries IN clause is based is empty, all rows are selected into the destination table. Hence it is advisable to check before-hand that the first table is not empty.

3. If the table on which the For All Entries IN clause is based is very large, the performance will go down instead of improving. Hence attempt should be made to keep the table size to a moderate level.

Not Recommended

Loop at int_cntry.

Select single * from zfligh into int_fligh

where cntry = int_cntry-cntry.

Append int_fligh.

Endloop.

Recommended

Select * from zfligh appending table int_fligh

For all entries in int_cntry

Where cntry = int_cntry-cntry.

============================================================================

Structure of Where Clause

When a base table has multiple indices, the where clause should be in the order of the index, either a primary or a secondary index.

To choose an index, the optimizer checks the field names specified in the where clause and then uses an index that has the same order of the fields. One more tip is that if a table begins with MANDT, while an index does not, there is a high possibility that the optimizer might not use that index.

In certain scenarios, it is advisable to check whether a new index can speed up the performance of a program. This will come handy in programs that access data from the finance tables.

============================================================================

Proper use of Move statement

Instead of using the move-corresponding clause it is advisable to use the move statement instead. Attempt should be made to move entire internal table headers in a single shot, rather than moving the fields one by one.

============================================================================

Proper use of Inner Join

When multiple SAP tables are logically joined, it is always advisable to use inner join to read the data from them. This certainly reduces the load on the network.

Let us take an example of 2 tables, zairln and zflight. The table zairln has the field airln, which is the airline code and the field lnnam, which is the name of the airline. The table zflight has the field airln, the airline code and other fields which hold the details of the flights that an airline operates.

Since these 2 tables a re logically joined by the airln field, it is advisable to use the inner join.

Select a_{airln a}lnnam b_{fligh b}cntry into table int_airdet

From zairln as a inner join zflight as b on a_{airln = b}airln.

In order to restrict the data as per the selection criteria, a where clause can be added to the above inner join.

============================================================================

Use of ABAP Sort instead of Order By

The order by clause is executed on the database server, while the sort statement is executed on the application server. Thus instead of giving the order by in the select clause statement, it is better to collect the records in an internal table and then use the sort command to sort the resulting data set.

============================================================================

Tools provided for Performance Analysis

Following are the different tools provided by SAP for performance analysis of an ABAP object

1. Run time analysis transaction SE30

This transaction gives all the analysis of an ABAP program with respect to the database and the non-database processing.

2. SQL Trace transaction ST05

The trace list has many lines that are not related to the SELECT statement in the ABAP program. This is because the execution of any ABAP program requires additional administrative SQL calls. To restrict the list output, use the filter introducing the trace list.

The trace list contains different SQL statements simultaneously related to the one SELECT statement in the ABAP program. This is because the R/3 Database Interface - a sophisticated component of the R/3 Application Server - maps every Open SQL statement to one or a series of physical database calls and brings it to execution. This mapping, crucial to R/3s performance, depends on the particular call and database system. For example, the SELECT-ENDSELECT loop on the SPFLI table in our test program is mapped to a sequence PREPARE-OPEN-FETCH of physical calls in an Oracle environment.

The WHERE clause in the trace list's SQL statement is different from the WHERE clause in the ABAP statement. This is because in an R/3 system, a client is a self-contained unit with separate master records and its own set of table data (in commercial, organizational, and technical terms). With ABAP, every Open SQL statement automatically executes within the correct client environment. For this reason, a condition with the actual client code is added to every WHERE clause if a client field is a component of the searched table.

To see a statement's execution plan, just position the cursor on the PREPARE statement and choose Explain SQL. A detailed explanation of the execution plan depends on the database system in use.

============================================================================

Plz reward me if the data is of help.

Regards,

Avik

Former Member · ‎2008 Apr 22

You can check the following for performance tuning.

reward if helps.

ABAP provides few tools to analyse the perfomance of the objects, which was developed by us.

Run time analysis transaction SE30

This transaction gives all the analysis of an ABAP program with respect to the database and the non-database processing.

SQL Trace transaction ST05

by using this tool we can analyse the perfomance issues related to DATABASE calls.

Perfomance Techniques for improve the perfomance of the object.

1) ABAP/4 programs can take a very long time to execute, and can make other processes have to wait before executing. Here are some tips to speed up your programs and reduce the load your programs put on the system:

2) Use the GET RUN TIME command to help evaluate performance. It's hard to know whether that optimization technique REALLY helps unless you test it out.

3) Using this tool can help you know what is effective, under what kinds of conditions. The GET RUN TIME has problems under multiple CPUs, so you should use it to test small pieces of your program, rather than the whole program.

4) Generally, try to reduce I/O first, then memory, then CPU activity. I/O operations that read/write to hard disk are always the most expensive operations. Memory, if not controlled, may have to be written to swap space on the hard disk, which therefore increases your I/O read/writes to disk. CPU activity can be reduced by careful program design, and by using commands such as SUM (SQL) and COLLECT (ABAP/4).

5) Avoid 'SELECT *', especially in tables that have a lot of fields. Use SELECT A B C INTO instead, so that fields are only read if they are used. This can make a very big difference.

6) Field-groups can be useful for multi-level sorting and displaying. However, they write their data to the system's paging space, rather than to memory (internal tables use memory). For this reason, field-groups are only appropriate for processing large lists (e.g. over 50,000 records). If you have large lists, you should work with the systems administrator to decide the maximum amount of RAM your program should use, and from that, calculate how much space your lists will use. Then you can decide whether to write the data to memory or swap space.

Use as many table keys as possible in the WHERE part of your select statements.

7)Whenever possible, design the program to access a relatively constant number of records (for instance, if you only access the transactions for one month, then there probably will be a reasonable range, like 1200-1800, for the number of transactions inputted within that month). Then use a SELECT A B C INTO TABLE ITAB statement.

😎 Get a good idea of how many records you will be accessing. Log into your productive system, and use SE80 -> Dictionary Objects (press Edit), enter the table name you want to see, and press Display. Go To Utilities -> Table Contents to query the table contents and see the number of records. This is extremely useful in optimizing a program's memory allocation.

9) Try to make the user interface such that the program gradually unfolds more information to the user, rather than giving a huge list of information all at once to the user.

10) Declare your internal tables using OCCURS NUM_RECS, where NUM_RECS is the number of records you expect to be accessing. If the number of records exceeds NUM_RECS, the data will be kept in swap space (not memory).

11) Use SELECT A B C INTO TABLE ITAB whenever possible. This will read all of the records into the itab in one operation, rather than repeated operations that result from a SELECT A B C INTO ITAB... ENDSELECT statement. Make sure that ITAB is declared with OCCURS NUM_RECS, where NUM_RECS is the number of records you expect to access.

12) If the number of records you are reading is constantly growing, you may be able to break it into chunks of relatively constant size. For instance, if you have to read all records from 1991 to present, you can break it into quarters, and read all records one quarter at a time. This will reduce I/O operations. Test extensively with GET RUN TIME when using this method.

13) Know how to use the 'collect' command. It can be very efficient.

14) Use the SELECT SINGLE command whenever possible.

15) Many tables contain totals fields (such as monthly expense totals). Use these avoid wasting resources by calculating a total that has already been calculated and stored.

Some tips:

1) Use joins where possible as redundant data is not fetched.

2) Use select single where ever possible.

3) Calling methods of a global class is faster than calling function modules.

4) Use constants instead of literals

5) Use WHILE instead of a DO-EXIT-ENDDO.

6) Unnecessary MOVEs should be avoided by using the explicit work area operations

see the follwing links for a brief insifght into performance tuning,

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

1. Debuggerhttp://help.sap.com/saphelp_47x200/helpdata/en/c6/617ca9e68c11d2b2ab080009b43351/content.htm

2. Run Time Analyser

http://help.sap.com/saphelp_47x200/helpdata/en/c6/617cafe68c11d2b2ab080009b43351/content.htm