How to find memory leaks using app dynamics - jvm

Could anyone explain me how to find memory leaks with the help of app dynamics.I tried to search but could not find any proper answer.

You can find detailed documentation on memory leak detection by AppDynamics from the following links (depending on whether you use Java or .NET):
https://docs.appdynamics.com/display/PRO40/Automatic+Leak+Detection+for+Java
https://docs.appdynamics.com/display/PRO40/Monitor+Memory+Usage+with+Object+Instance+Tracking+for+.NET

Related

Understand Heap-dump and Thread-dump for Large-scale application

I go through some tutorials of Java Profilers (JVisualVM, JProfiler, YourKit) on Youtube as well as Pluralsight. I got a little bit idea regarding how to check heap-dump and how to find the memory leak. But these all tutorials are elementary.
My query is, when I analyse in heap-dump, I saw only 3 types of objects char[], java.lang.String and java.lang.Object[] which covers almost all memory(more than 70% always). But none from my application.
And the same way for thread dump, I saw HTTP-8080 request (the port I am using) and that leads me to Runnable()'s run method or Java Concurrent Package and again not to any specific code to my project.
I also discussed the problem with some of my friends and analyse their application as well (which doesn't face any issues regarding memory leak and performance), but their results are almost the same.
Would you guys help to understand how to analyse heap-dump and thread-dump in JVisualVM for the large scale application? Any video, blog, anything would be helpful.
I am using OpenJDK-11, AWS ECS-Docker and Tomcat as a web-server.
Checkout the Eclipse Memory Analyzer (https://www.eclipse.org/mat/), I used it in the past several times to successfully find memory leaks, but it takes some time to get familiar with it.
Another advise I can give you is to create benchmark tests with Apache JMeter (https://jmeter.apache.org/) or another tool that lets you reproduce the performance/memory issue and identify the execution path that cause you problems.
Be aware AWS doesn't like when someone execute performance/penetration tests against their services (https://aws.amazon.com/aup/)

How to automate memory allocated (to find memory leaks) for an app using Robotium

I have to create a test suite to test for any memory leaks occured after doing some operations on my app. So can anyone guide me how to implement it using robotium. I'm able to achieve it a bit but need more help
Test script to find memory leak:
boolean value=Debug.dumpService ("com.apppackage.name", fd, null);
ActivityManager manager=(ActivityManager)getActivity().getSystemService(context.ACTIVITY_SERVICE);
List<RunningAppProcessInfo> service= manager.getRunningAppProcesses();
for(int i=0;i<service.size();i++){
if (service.get(i).processName.equals("com.apppackage.name"))
{
pid=service.get(i).pid;
}
}
android.os.Debug.MemoryInfo[] meminfo=manager.getProcessMemoryInfo (new int []{pid});
Log.d("meminfo",meminfo+"length");
String info = meminfo.toString();
The Solo class that Robotium uses to assist with testing has the method assertMemoryNotLow() which will cause your test to fail when it is invoked if the Android OS considers memory to be low, for example if you create a lot of Bitmaps without recycling them when you're done.
As for fully implementing your suite with Robotium, that kind of open ended question is outside of the scope of Stack Overflow. You can visit this link Getting Started With Robotium to see an example of how Robotium is used. It has a very useful link to download a test project created by the developers which should be enough to get you going. Once you've started, feel free to come back as you encounter challenges and ask some specific questions about the framework; the community will be happy to help. Good Luck!

Help diagnosing crash in Cocoa framework - possible memory leak?

I'm currently migrating the Fragaria framework from a GC-only environment to GC being supported. After the work was done (or what I thought had to be done to make it work) I was able to run the examples that come with the framework without any problems and Instruments didn't show any major memory leaks.
I included non-GC Fragaria in my non-GC application and it crashes as soon as I place the cursor on it. To be honest the usage pattern is different from the examples as I'm embedding it in an instance of NSViewController instead of NSDocument.
Can you give me some tips on how to debug this? I'm a bit lost on where to proceed now.
First thing to do is Build and Analyze the code, then fix any problems it finds.
Next, try running with Zombie detection enabled (google NSZombie).
Finally, each crash's stacktrace should give you a pretty good idea where things have gone off the rails.

Why am I having memory leaks using Instruments on the device but not on the simulator

I am getting close to finishing the release of my application and are trying to use Instruments to fix any memory leaks.
How come that I can spot one memory leak when using Instruments and my device but not when I am using the iPhone simulator? I understand that this is a high-level question, but I don't think posting any code would help anyways (quite a bit of code...).
And is it possible to get instruments to point to the source code where it think the leak is? I can do it when using the simulator, but it seems like it doesn't work when using it for the device (objects are represented by the address (I assume) while running it for the simulator it sees what object it is, setup issues?)
Thanks in advance!
Regards,
Niklas
Update: Could it have something to do with that OSX is having automatic garbage collection but iOS doesn't?
Trust only the device. That's what your user will use to run your application.
Don't trust the simulator.
As a demonstration of this, I just intentionally added a leak to a project. The leak was not detected while in the simulator, but showed up as expected on the device.
The simulator is just that: a simulator. It can be useful to work faster, but is never a replacement of the device.
Once Instruments showed you a leaked object, you can double click on it. It will show the part of your code responsible for the leak. This works for the simulator and the device.
When you compile for the device, make sure you are in debug mode (and that the settings for this mode kept all your symbols).
Some more tip that you might find useful:
For a more fluid session, disable the "Automatic Leaks Checking", and manually press the "Check for Leaks Now" button when appropriate.
The "Build and Analyse" command will do a fantastic job to help you find leaks. It's not (totally) magical, so it won't find all leaks. For example, iVars leaked won't be identified. But for the scope of a method, it's just awesome.
I highly recommend to activate the "Run Static Analyser" flag in your build settings (or only for the Release mode if you have a slow to compile machine).
If you want more info about how to use Instruments to find leaks, read this Apple doc: Instruments User Guide: Built-in Instruments and Instruments User Guide: Viewing and Analysing Trace Data > Looking for Memory Leaks
You can also watch the video of the WWDC related sessions.
If you still don't understand where your leak come from, it's time to (re)read the Memory Management Programming Guide.
Thank you for wanting to ship a leak-free application. With iOS 4, it's now more important than ever.
If you haven't already take a look at the handy "Build and Analyze" option in the build menu. It will run the static analyzer which generally does a great job. If nothing turns up with that you should could some time reviewing the WWDC session videos on Instruments.
There is no substitute for profiling on hardware and with the debugger and instruments connected you can get everything you would in a simulator context.

Out of Memory errors - tool for finding classic ASP memory leaks?

I am getting Out of Memory errors in classic ASP, probably where attempting to access data. For example:
Microsoft VBScript compilation error '800a03e9'
Out of memory
(some file) Line 0
These errors only happen once in a while and they keep happening for a few minutes and then the webserver must be restarting the app pool because all sessions are lost.
What is a good tool for finding/diagnosing memory leaks in a classic ASP application that makes heavy use of ADO for data access and a couple of other off the shelf COM objects.
Presumably any memory leaks would be from the COM object rather than the script, so a general Windows debugger or leak finder might be what I need. Any advice on what would be appropriate?
Or any other thoughts on what might cause these errors?
Unfortunately, tracking down memory leaks is not an easy task :-(
Here's a good summary of things to watch out for here:
http://www.leinadium.com/code/classic-asp-memory-leaks-in-iis/
Be sure to read the link inside that post as well for a list of tools.
Good luck!
Microsoft has a good utility umdh.exe that may be good for finding leaks in this situation. It allows you to take a "snapshot" at one point, exercise the application (e.g., IIS) then take another snapshot and compare the memory usage differences.
if
you try to get one row data with EOF OR BOF
or
the database connection is close or readony you try to wirte!
you should get the ERROR.