High memory usage when file generated using EPPLus library - memory-leaks

HI All,
Using ANTS memory profiler, I noticed that in a process of creating Excel file using EPPLUS(3.5 MB) on IIS, a lot more memory (150MB) is added to IIS Worker Process (w3wp.exe). The memory count does not go down after a download is completed. I use pretty much the same code as this one: http://epplus.codeplex.com/SourceControl/changeset/view/c5783b32e89e#SampleApp/Sample1.cs.
EPPLus has everything I need. Except this little problem. I have also seen a few "out-of-memory" threads and none of them seems to be resolved. Please let me know if someone has faced the same issue and fixed it.
Generation 2 is holding lot of objects.
Problem: ExcelCell Object is held in generation 2. How can i clear this without calling GC.Collect()
Thank you.

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https://github.com/c4milo/node-webkit-agent
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That is a massive jump in versions. You may want to share what code changes you may have made to get it working on latest stable. The api is not the same as back in v0.3, so that may be part of the problem.
If not then the issue you see it more likely from heap fragmentation than from an actual leak. In later v8 versions garbage collection is more liberal with cleanup to improve performance. (see http://code.google.com/p/chromium/issues/detail?id=112386 for some discussion on this)
You may try running the application with --max_old_space_size=32 which will limit the amount of memory v8 can use to around 32MB. Note the docs say "max size of the old generation", so it won't be exactly 32MB. Just around it, for lack of a better technical explanation.
Also you can track the amount of external memory usage with --trace_external_memory. This will allow you to know if external memory (i.e. Buffers) are being retained in your application.
You're note on the application hanging around 1.5GB would tell me you're probably on a 64-bit system. You only mentioned it ceases to function, but didn't note if the CPU is spinning during that time. Also since I don't have example code I'm not sure of what might be causing this to happen.
I'd try running on latest development (v0.11.3 at the time of this writing) and see if the issue is fixed. A lot of performance/memory enhancements are being worked on that may help your issue.
I guess you have somewhere a memory leak (in form of a closure?) that keeps the (not longer used?) diagrams(?) somewhere in memory.
The v8 sometimes needs a bit tweaking when it comes to > 1 GB of memory. Try out --noincremental_marking and/or --max_old_space_size=81920000 (if you have 8 GB available).
Check for more options with node --v8-options and go through the --trace*-parameters to find out what slows down/stops node.

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Using WINDBG (!eeheap -loader), we noticed the that the LoaderHeap is getting bigger (150MB increase per day). From the !eeheap output it seems that the increase is due to HostCodeHeap (objects?).
I'd like to know what are these objects and why how can I prevent them from growing to infinity.
Thanks!
They are likely objects created for dynamically emitted code. Several components in the framework do this, and it may well be that IronPython uses some on its own.
I'd heard of similar issues while using Linq-TO-SQL, XML serialization, compiled XSLT transforms and other dynamically generated code.
See also "Leaking Unmanaged Heap Memory" near figure 2 in this MSDN magazine article.

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Mobile devices are usually very low on memory. So you have to use some tricks to conserve and use memory.
We had the same problem at a project of ours and we solved it like this.
for downloaded images:
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Hope this helps.
There are a few things that might be happening here:
You might have seen the memory used before garbage collection, which doesn't correspond to the actual memory used by your app.
Some third party code you are running might be pooling some internal datastructures to minimize allocation. While pooling is a viable strategy, sometimes it does look like a leak. In that case, look if there is API to 'close' or 'dispose' the objects you don't need.
Finally, you might really have a leak. In this case you need to get more details on what's going on in the emulator VM (though keep in mind that it is not necessarily the same as the phone VM).
Make sure that your emulator uses JRE 1.6 as backing JVM. If you need it to use the runtime libraries from erlyer JDK, use -Xbootclasspath:<path-to-rt.jar>.
Then, after your application gets in the state you want to see, do %JAVA_HOME%\bin\jmap -dump:format=b,file=heap.bin <pid> (if you don't know the id of your process, use jps)
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I had a similar problem with LWUIT at Java DTV. Did you try flushing the images when you don't need them anymore (getAWTImage().flush())?
Use EncodedImage and resource files when possible (resource files use EncodedImage by default. Read the javadoc for such. Other comments are also correct that you need to actually observe the amount of memory, even high RAM Android/iOS devices run out of memory pretty fast with multiple images.
Avoid scaling which effectively eliminates the EncodedImage.
Did you think of the fact, that maybe loading the same image from JAR, many times, is causing many separate image objects (with identical contents) to be created instead of reusing one instance per-individual-image? This is my first guess.

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