My first question is what you mean by “reference”. There are no references in Elixir. There are only the data themselves.
Secondly, when a data structure, like a map here is modified, the underlying BEAM does not make a complete copy of the whole structure, although it appears to at the Elixir level abstraction. It’s actually some pretty clever data structure manipulation that can maintain mostly a limited memory impact.
I’ve found some clues to how this all works here. But to be honest, at the programming abstraction, I don’t know how to predict how it will perform.
