Best way to implement the server-side of a online turn based game?

My friends and I are creating a multiplayer online turn based strategy game. The game has a lot of mechanics and is considerably complex. The server must be authoritative (it calculates every player’s action). We need to find which is the best solution for our server to know what is the current game state, in order to be able to answer to all the player’s requests.

We came up with two different approaches to do this, but we don’t know which one to choose or what are the advantages/disadvantages of each:

• We can keep a copy of the game state from each game in memory (similar to how the client will work) and the information is gathered from the objects inside this game instance.

• Or, we can have a database with all the relevant information and the server will query it in order to gather the necessary information.

Since we want to be able to reproduce any match later (for analyses and statistics purpose), the “extra” work required to build the data base in the second solution can’t be considered a disadvantage for that solution.

It might also be relevant to point out that we are going to be using the new Unity Networking and not other framework.

Thank you for your time! =)