Where does it say that?

It says things like:

“We were not creating a lot of garbage.”

... but that statement there doesn’t say anything about the heap size, including the size and count of live objects (i.e., not garbage).

It also says:

“There are millions of Users in each cache. There are tens of millions of Read States in each cache.”

Large is often in the eye of the beholder, but I missed it if it said anything specifically about not having a large heap size.