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Java Earlywatch Alert report – Is it telling the truth ?

The question

Hello SDN Community

With the title I hope to attract a broad audience as I believe it’s an important topic for both implementation partners and customers.

With more and more SAP systems being born into this world and many Java based (or dual stack) SAP systems in use, the need for health checks and monitoring of Java instances increases.

A good report to get an overview on the key performance indicators of your SAP Java is the Earlywatch report, or not?

The answer

SAP Note 976054 provides information on how to setup EWA (Earlywatch Alert) for non-ABAP components such as Enterprise Portal and so on.

The demand for performing the setup of diagnostics scenario and all involved components (Wily Introscope, Diagnostics Agent) has gone up and is becoming parts of the standard setup at customers who have SAP Java instances running.

Once all those components are in place and working, you can either have a separate EWA report for a Java only SAP system or an additional section in the report for a dual stack (ABAP and Java based) SAP system. The portion on java features the key performance indicators and gives a good view on how well your SAP Java is running.

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Picture 1.1

You can see in picture 1.1 that the report states the performance and workload data is available.

What does that mean ? It means that the infocubes in which the data is saved contain data (the infocube is active).

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Picture 1.2

You can see in picture 1.2 that average (%) of time spent doing garbage collection was “0.00” and the max (%) of time spent doing garbage collection was also “0.00”. For those who are not familiar with garbage collection, you can read the following blog SAP Java Administration – Troubleshooting part II – understanding garbage collection basics which explains the basics of garbage collection: using a simple example of an application which represents a qualification race (yes I’m a car fanatic).

Now let’s reflect on those numbers, is it possible the value of both metrics is 0.00? Unless your Java based SAP system was down the whole week, the answer is no!

Even when your SAP system is starting up it’s very likely to have garbage collections already (minor), while it doesn’t take much time, it does take some time and minor garbage collections occur frequently.

The value can be very little if you have a well oiled Java SAP system, for example “0.17” but not “0.00”. The recommendation is to have less than 5% of average time spent on GC (garbage collection).

Conclusion

Having an Earlywatch reports for your Java based SAP systems or Java stacks (in case of a dual stack) is a good idea but you have to be careful with some existing pitfalls.

When a customer views the result and it’s all green and everything is in order then they rely on what the report states. Even though the data is available, it is possible the data is captured wrong or handled incorrectly which gives an end result rating which is not the truth.

To tackle this point, a check should be build in and give a warning that the result might be false because the metric value seems to be impossible.

For the administrators, there is the task to verify if the data is indeed possible and correct the capturing of data through diagnostics which can be an challenging root cause analysis.

Another point which is not integrated by default is the availability of data in the Earlywatch Alert report for your SAP J2EE Dispatcher (only valid for SAP Netweaver 6.40 – 7.0 – 7.0x).

If you want to have data on key performance indicators of your SAP J2EE Dispatcher you have to perform additional setup steps. SAP has recently documented those steps and they are available in SAP Note 1424719 – Wily Introscope Instrumentation for SAP J2EE Dispatcher.

I can certainly recommend you implement the dispatcher instrumentation as the dispatcher can be the cause of crash situations (sizing too small, not enough threads available in the dispatcher).

One thing everyone should do is reflect upon what is in front of you, does it make sense?

2 Comments
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    • Hello Samik

      You would have to start from the beginning and check each component until you reach the point where your EWA is created.

      One of the first things you should check is if the data captured in Wily Introscope is correct.

      Is the garbage collection data collected in Wily Introscope? Are the values realistic (check again the log file where the garbage collection is logged in)?

      If the answer to both questions is yes then you should check your SMD (Solution Manager Diagnostics) agent. Is it gathering the data from introscope properly (check the agent logs)?

      Perhaps your agent didn't run for a certain period of time ?

      If yes, is the data written into the BI Infocubes properly ? You are bound to encounter something that is wrong when going through the whole process which gives the end result which is incorrect.

      It's too much to go through each and every possibility. I call finding the root cause of such an issue "the art of troubleshooting" which is my next blog to be posted on SDN.

      Kind regards

      Tom