ASP.NET: Large memory leak.. Where is it? DB? Updatepanels? No disposables?

I have been developing a quite large application, and I uploaded it to my server some days ago. Now I have found out it has several memory leaks - Uh oh. My server is running Windows Server 2008 on 1GB ram. When I have 0 people online, only 550-600mb is used. When one people comes online the memory starts skyrocketing, and if 3-4 people are online all 1GB ram is used.

The application is made in ASP.NET with AJAX. It has many updatepanels which runs every second and quite a lot of javascript. It uses 5-7 sessions at all times. I use LINQ to SQL as database communication.

I tried pe开发者_如何学Pythonrfmon.exe on my server, and I found:

• Gen 0 collections goes from 0% to 100% within minutes
• Gen 1 collections goes from 0% to 50% within 5 minutes
• Gen 2 is very close to 0% at all times
• Total heap bytes goes up to 100% very fast

I also ran an analysis of my program with Visual Studio. 8% Of my total runtime is done in .ToList() methods, which properly is caused by LINQ to SQL.

My theories....

(1) Linq to SQL dataContext

This might be a crazy thing to do, but: In my data access layer I have a load of methods:

• AddSomethingToDatabase();
• AddSomethingElseToDatabase();
• DeleteSomethingFromDatabase();

Each of these has the following initialization:

GameDataContext db = new GameDataContext();

Which means the above statement runes nearly every second or more.

(2) No objects implement IDisposable

I have to be honest: I have never worked with IDisposable. As far as I have read, this might be a problem.

Also, if this is the leak, which classes should implement it? I do not have any I/O work or others, only the DataContext.

(3) Loads of UpdatePanels and jQuery

I have some fear loads of updatepanels can give problems with performance, but I do not know how to check it.

So my question is: Any ideas on what the memory leak could be? Any ideas on how to find the memory leak? And any ideas on how to solve it?

I would love to hear from someone who has experience with the situation above!

Thanks, Lars

I am not sure at all that there is a problem here. All the suggestions for memory leak troubleshooting seem to be just really bad advice when you have not yet established that you have a memory leak since your memory on the server is so low that this cannot be established.

So here is my 2 cents - some might not like it but as long as it could point you at the right direction, I do not mind the downvotes.

It seems that you have a very stringent memory requirement. 1GB of RAM for a Windows 2008 Server just gives about enough RAM to do its OS related job. This is way way below recommended RAM requirements for it which if I am not wrong is minimum 2 GB RAM. Overhead of just running a w3wp.exe and IIS would be around 200-300 MB. The fact that generation 2 is always is around 0% is the best evidence that all looks good and your server is probably being starved of the memory.

My suggestion is to give your server at least 2GB of RAM (4GB should be better) and then monitor the memory usage and see if it is going up. If so, post another question with your findings and we should be able to help.

You absolutely must ensure that IDisposable objects get Dispose called when you are done with them. The simplest way to do this is to use using:

using (GameDataContext db = new GameDataContext())
{
    // code that uses 'db' goes in here
}

// Dispose called when 'using' scope ends

If you still have problems after doing this throughout, then profiling is needed, but fix this first since it's a no-brainer.

Your own objects usually only need to implement IDisposable if they encapsulate unmanaged resources for which you wish to guarantee deterministic release back to the OS, so that those resources - file handles, sockets, and so on - are not sitting around waiting for GC for an interval of time you cannot rely on.

I don't have an answer for your question 3), sorry.

I'd recommend you use a memory profiler. Redgate's ANTS is pretty superior; it can give you a breakdown of which objects are in memory at a given time.

I am not expert at this. But If you try ANTS Memory Profiler might help you figure out where the problem is.

Scitech memory profiler found our leaks and gives good advice.