How to Use Debug Standard tcode in SAP ABAP

The purpose of this article is to how to use SAP ABAP standard debugging tools to debug programs. It may come at no surprise that as a functional or a techno-functional consultant, you might need to debug the program behind the transaction, say for example ME21N to see where is the program stopping and producing errors. This usually happens in the following cases:

• After an Enhancement update
• Support pack installation
• User-exit bug

Debugging is when you stop a program or transaction at a certain point, so you can walk step by step through the ABAP programming to see where an error occurs.

But as functional consultant you need basic ABAP skills to be able to do this, Most good functional consultants will have basic debugging skills and this is very very important because it reduces the excessive independence to ABAP teams.

Most of the time, part of our workload is to resolve errors that occur during the execution of certain transactions. However, if these errors message cannot be resolved by setting up the master data or transactional data (i.e.: error message without any meaning) you need to access the program in debug mode (by typing “/h” in the transaction bar and then executing the transaction), which will allow us to analyze the program and see where the problem lies, and thus save time.

Important transaction code in ABAP Debugging

Here we have two important transaction code: SE38/SE37

SE38: is a transaction code that allows you to display/change/create ABAP Program.

SE37: is a transaction code that allows you to display/change/create Function Module.

Function Modules: are set of codes that can be reused by others programs and FM can be executed independently.

Let’s take an example: Function Module: (SD_ROUTE_DETERMINATION)

This FM is used for the logic of route determination

Now let’s open this FM with help of the SE37 transaction code

What is a Breakpoint in SAP?

In ABAP debugging, the notion of breakpoint is a very important notion because the breakpoint is used to interrupt the processing of the program and launch the debugger.

When you are in the ABAP editor (SE38) the two breakpoint icons are displayed at the top of the page

Left session breakpoint and right external breakpoint

To set a breakpoint in an ABAP program, simply select the line of executable code and click on one of the icons above.

Now let’s discuss the meaning <<Session breakpoint>> and <<external breakpoint>>

Session Breakpoint:  Specific to a particular ABAP user session. If the user session is ended (log off sap system) all session breakpoints get deleted.

External Breakpoint:  They are applied to the current user session as well as future user sessions.

The other thing to remember here is that you can put a breakpoint on almost anything, for example if you think your problem is with specific ABAP statements ( IF…..ENDIF, SELECT, LOOP ); function modules or methods .

For that you have to go to the breakpoint creation menu

Important:  An ABAP program can contain hundreds or even thousands of lines of code, so it is impossible to go through the program line by line to find the problem. It is therefore essential to master the use of breakpoints because if you think the problem is at a certain level in your program, you can simply place your breakpoint at that level and SAP will stop processing the program at that level and run the debugger.

Debbuging Screen

To explain the debugging screen, I will use the transaction (ME21N), typing “/h” in the transaction bar, then running the transaction. This will allow us to access the program in debug mode.

You will probably see the screen below

Let us discuss this section by section

At the top of the debugging screen

Here you can easily read the name of the program and also see the event being processed (function/method).

To take the process forward step by step you can use the icon strip:

Now let us discuss one by one:

Structure fed and updated throughout the processing.

We will see here 2 important SYST structures:

SY-SUBRC: is SAP ABAP system field and contains a return code of ABAP statements. This value is used to determine the status of the execution of an ABAP statement.

Important: if SY-SUBRC is 0 the ABAP statement has been executed successfully if the value is different from 0 then the statement has raised an error or warning.

SY-TABIX: returns the number of the current line in a processing loop

What are Watch Points in SAP?

Can be set on a variable you want to monitor to stop program execution when the contents of that variable change, but only you need to ensure that the variable is declared globally in a program

What’s even more interesting about watchpoints is that you can set them to fire when specific conditions are met (for example, you give your variable a fixed value) instead of firing every time the variable changes, because your variable may change at several places in the program.

Most of the time, an internal table contains thousands of rows and if we need to debug a particular row, for example the item number which is in the 300th row of an internal table, knowing that this internal table contains more than 10,000 rows in this case, it is very difficult, if not impossible, to debug an internal table row by row to reach this particular row.

In order to save time, it is sufficient to define a watchpoint for the particular value of a field or variable.

How to use a watchpoints? Let’s take 2 scenarios:

Scenario 1

In our custom program we want to see the behavior of one particular variable we will ask SAP to stop the program when it reaches this variable for achieve our goal we will use watchpoints let’s see how

Go to se38 and open your program in debug mode

Create watchpoint

Put the name of variable you want to check and click on the green button

You will get this message

You can also check in watchpoints tab

And execute the program (F8)

And finally you will get this confirmation message

Scenario 2

For example, there are 386 entries in the internal table.  Let’s see how to analyse the 227th record, i.e. the PO number “4500001592”.

Go to se38 and open your program in debug mode

How to Create a watchpoint

Because we want to see a particular value, we will create a watchpoint but this time our variable will be a ‘work area’ with the field corresponding to our value.

You will get this message

You can also check in watchpoints tab

And execute the program (F8)

And finally you will get this confirmation message

Changing Variable Values

One of the important features of the SAP debugger is the ability to change the values of variables “on the fly”.

Sometimes, when we debug for testing purposes, we need to change the values of variables in order to test several scenarios or to see the behavior of the program.

And even during troubleshooting, changing the value of a particular variable can help solve the problem.

However, it is important to ensure that you have permission to do so, otherwise the system will not allow you to change a field. You should therefore contact the SAP security team to obtain the necessary permissions.

Let’s see how we can change the value

For the testing purpose we will change the PO number (from: 4500001592 to: 4500001630) to see the behavior of the program

Click to pencil icon to make the field editable

Now we can change the PO number easily

Debugging pop up screen

In SAP we encounter pop-up screens every day, but there are scenarios where a pop-up screen needs to be debugged to find the exact cause of the error.

One of the most important difficulties is that command line debugging is not possible if pop-up screens appear: because you cannot edit /h

What you need to do is save the line of codes below to a text file on your laptop or desktop.

And when it’s time to debug, just drag and drop the text file you saved on your desktop or laptop onto the pop-up screens.

Let’s take an example

During a transaction, we get this pop up screen here below

Our task now is to find out exactly which line of the ABAP code contains this error by debugging.

Just drag and drop the text file you saved on your desktop or laptop onto the pop-up screens.

You will get this message

And click on the green button

The program will stop exactly at the point where this error occurs.

Debugging of Enhancement

Before we talk about debugging enhancement let’s see first what is enhancement and what is the purpose of enhancement?

SAP Enhancements: enables customers/clients to add custom business functionality to sap standard software without changing at all the sap standard functionality (which is supposed to be unchanged).

But to better manage the enhancements in the program and also to be sure not to change the standard functionality of the sap, the best thing to do is to copy a standard program and make the enhancements you want.

Now let’s see how we can debugging enhancement

Two things you should keep in your mind before starting debugging enhancement:Icon snail :

And(the F5 key) button remember (The F5 key): Allows you to execute the code line by line

Go to se38 and open your program in debug mode

Identify the snail icon in the program as shown below

 With the (F5 key) you can start debbuging your enhancement step by step

Debugging an error message

As I explained earlier, in some cases SAP error messages are not useful, which means that we don’t know what caused the error. In such a situation we have no choice, the only method of troubleshooting is debugging.

Let’s see how we can debug error message

A user sends you this screenshot by email:

Our task now is to find out exactly which line of the ABAP code contains this error by debugging.

Open the program in debugging mode

Go to breakpoint at message

Enter the information contained in the error message

And execute

As you can see above the program has stopped exactly at the point where this error occurs. Please let us know if you have any comments in the comment section. I hope you enjoyed my article