Entity framework memory not released

Question

I'm using a very simple asp.net mvc application with Entity Framework 6.0.2, .Net 4.5.1:

public class HomeController : Controller
{
   public ActionResult Index()
   {
      int count;
      using (var db = new LocalContext())
      {
         count = db.Counters.Count();
      }
      return View(count);
   }
}

public class Counter
{
   public int Id { get; set; }
}

public class LocalContext : DbContext
{
   public DbSet<Counter> Counters { get; set; }
}

If I do a load test on it, I eventually get an Out Of Memory Exception. (tinyget -srv:localhost -port:<port> -uri:/home/index/ -threads:30 -loop:5000). In Performance monitor I see the generation 2 Heap steadily grow. If I use a smaller loop value (say 500), the size grows until tinyget stops. Then the heap size stays the same (for at least 20 minutes, after that I stopped the server).

What am I doing wrong?

EDIT

So I tried Simon Mouriers suggestion and left out the EF code. Then I don't have memory problems. So I thought, maybe if I use Release instead of Debug, it will make a difference. And it did! Memory was released after a while and I could put high load on the site. Then I switched back to Debug to see if I could get more info and... even in Debug mode no problems anymore. FML, I worked a day on it and now I can't reproduce it anymore.

Answer 1

In your case the internally managed class that inherits from DbContext would then need to implement IDisposable and inside of the LocalContext add the following:

public void Dispose()
{
    this.Dispose(true);
    GC.SuppressFinalize(this);
}

protected virtual void Dispose(bool disposing)
{
     if (disposing)
     {
        // Manage any native resources.
     }
   //Handle any other cleanup.
}

Without specifically overriding the call to dispose, the using statement is only going to call Dispose() against the base class, while you need to dispose of the parent and base.