Memory problems in ASP.NET

Question

I got problems with memory in my asp.net application. The problem is that I can't see any problems when running it locally (between 100-200mb) but on the production system I get 503-errors because of the memory limit (512mb) being reached (running it on shared hosting).

How can I pin down the problem? I don't think that I have access to the current memory usage, at least I have not found any way and the company who hosts my site says that there is no way.

I have absolutely no experience tracking down memory leaks. :)

Thanks

Answer 1

I don't know that this is completely answerable here, but here's a start for you... The other answers are addressing specific memory issues, but tirst, you need to understand how memory is allocated and deallocated (reserved, used, and released) by the computer, the .NET runtime and in turn, your program.

Then you need to understand your code well enough to understand which functions happen on a per-user bases, and look at how much memory is being used. From there, you can get into your code and track down issues, but you need a firm understanding of the basics.

If I were you, I'd start with this article, and plan on spending some more time researching and learning. Hoefully, this article will not only answer questions, but give you enough knowledge to ask more specific/better questions. It's a good article, and I believe it will really help you, but it's not the whole kit-n-kaboodle. There's a quite a bit to learn.

http://msdn.microsoft.com/en-us/magazine/cc188781.aspx

The article is a bit old, and I'm assuming you're using more recent tools, so when you're done digesting that article, jump to http://msdn.microsoft.com/en-us/library/ms182372.aspx to learn about the Visual Studio Profiler.

Answer 2

This isn't necessarily an answer to your problem, per se, but more of a suggestion as to how to track things like this down.

One thing that I've found helps in tracking down these sorts of issues is to build into your application some sort of instrumentation. It could start as simple as providing a cache of sorts to keep track of pages request durations. This could be accomplished by creating a static cache class to hold either all (not recommended) or just long-running requests that you define (a safer approach) and have it all triggered in the OnBegin and OnEnd events (an HTTP module would be ideal). You could then create a basic dashboard page to list the contents of the cache to see potential places for trouble.

Answer 3

First things first... 503 is not only because of memory. If your application crashes 5 times in 5 minutes, due to rapid fail the application pool gets shut down and you get 503 - Service unavailable error.

500 MB odd memory seems pretty less to me and hence, memory could be adding to your problem. If it is 503 error, it means you have troubleshoot the issue from a crash perspective. Link

If you are having memory issues, you will typically get Out of memory exceptions, in which case, you should take multiple memory dumps of your process (w3wp.exe) and analyze it. Link has many posts on how you should analyze the memory dumps for memory leak. Right now, it would be too early for you to call it a memory leak.