Whenever we use count in the end `count_documents` in Mongo::Collection::View::Readbale is called. This builds a pipeline with `$group: { _id: 1, n:

}``

On a collection with about 3 mio documents this takes over 15 seconds to execute and consumes about 20 gb of memory.

In my opinion this is a bug - or maybe a misunderstood feature?
Can someone help me here?