it can't. if it's a server side turn based game, server works only as much as players (1 per current turn) pushes data up on server.
unless you have a huuuuuge amount of players at the same time, then you're pretty much ok. if you do have ~1000 or more players pushing data onto server at the same time (ending their turn) this could slow things down. still you would have to do this - make asycn calls to database so they are queued up for processing, and since servers can easily process ~1000 connections at once, they will be processed in a matter of minute / two /etc.. other players wait until they have the turn. it can take that minute two or more since they don't know when really the other player is done, and through pings on database you should check turns.
also if someone DC-s, make it a permanent DC and make sure when it's that players turn, to automatically skip it.
Thanks for the reply !
What if we make peer to peer system to peer = host system ?
I mean if i use my computer as a server , and keep it open always , can it handle the server mission completely ?
So there won't be any troubles if anyone leaves ?
It's like peer(server = my computer) to peers.
A stable peer done all the work so if players disconnect or else it wont change the games current play.