Hello everyone :).
I’m actually making my game, it is a online game, and i would some advice for my server,
Actually i got working the all thing: (not so much)
Custom c++ packet system with encrypt etc.
Full login logout system with error code etc.
Character creation selection delete etc.
Third party c++ server communication with ue4 socket.
On the server side i actually made a threadpool acceptor to create user for each connection.
And now i’m starting to make the “Instance - Session” or call it as you want, but i would get some help to be sure i’m not going fully wrong…
‘Single game’ :
Creating a new Session() -> thread it. (i would thread it for the Update loop)
Creating a sub instance for the current map and spawn mobs -> thread it too. (same)
‘Grouped game’ :
Creating a new Session() -> thread it. (i would thread it for the Update loop)
Creating a sub instance for the current map and spawn mobs -> thread it too. (same)
But here if a player choose to go on an other map i would create inside the Session an other sub instance for the new player map.
A picture to show you as far what i’ve on my mind.
So if anyone have allready made something similar any help would be great, because i don’t want to write so many code if it is absolutly wrong :).
Thank’s ! 
ps: i’m sorry for the pics quality but paint is paint ahah.