Gen 1 allocated 3GB of free space

ddp74

I've been trying to work out why our app pools are consuming anywhere from 2-4GB of memory on our production servers (according to the working private set memory usage on the process monitor). We don't see anywhere near this amount of usage in development using the same customer database. Development laptops tend to allocate 400MB-600MB.

I used memory profiler 8 on an app which was showing in process monitor as using 3GB. The profiler showed that 97% of this was free space. After checking the session overview, I saw that the Gen 1 Heap has 2.906GB of "space that isn't being used".

I believe the problem could be related to loading a lot of data (millions of rows) on app start through an ORM. So that pushes up the memory allocation in Gen1 because they're not immediately disposed until all the caches are built. But for some reason Gen1 is still allocated all of that memory.

Is there an actual reason for this? Is there any way to reclaim that memory?

ddp74

To answer my own question, this is expected behaviour of the GC (https://msdn.microsoft.com/en-us/library/bb384209%28v=vs.110%29.aspx).

The solution is to just reduce the amount of data we consume when constructing our caches.