MVC ASP.NET is using a lot of memory

Question

If I just browse some pages on the app, it sits at around 500MB. Many of these pages access the database but at this point in time, I only have roughly a couple of rows each for

Answer 1

Because the file is large, it is allocated on the Large Object Heap, which is collected with a gen2 collection (which you see in your profile, the purple blocks is the large object heap, and you see it collected after 10 seconds).

On your production server, you most likely have much more memory than on your local machine. Because there is less memory pressure, the collections won't occur as frequently, which explains why it would add up to a higher number - there are several files on the LOH before it gets collected.

I wouldn't be surprised at all if, across different buffers in MVC and EF, some data gets copied around in unsafe blocks too, which explains the unmanaged memory growth (the thin spike for EF, the wide plateau for MVC)

Finally, a 500MB baseline is for a large project not completely surprising (madness! but true!)

So an answer to your question why it uses so much memory that is quite probable is "because it can", or in other words, because there is no memory pressure to perform a gen2 collection, and the downloaded files sit unused in your large object heap until collection evicts them because memory is abundant on your production server.

This is probably not even a real problem: if there were more memory pressure, there would be more collection, and you'd see lower memory usage.

As for what to do about it, I'm afraid you're out of luck with the Entity Framework. As far as I know it has no streaming API. WebAPI does allow streaming the response by the way, but that won't help you much if you have the whole large object sitting in memory anyway (though it might possibly help some with the unmanaged memory in the (by me) unexplored parts of MVC.