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i am very new to MongoDB and NoSQL in general and i've just started building a site with MongoDB / Norm / ASP.NET MVC 3.

I am wondering how i should be scoping the connections to my Mongo database.

Right now i have a Basecontroller that instanciates the MongoSession and onActionExecuted i dispose it so all my deriving controllers will have access to my MongoSession. The MongoSession class opens a connection in its constructor and disposes it on Dispose(), the way it's working today.

private IMongo _mongo;

public MongoSession()
{         
    _mongo = Mongo.Create("connString");      
} 

public void Dispose()
{
    _mongo.Dispose();
}

I am a bit worried it might be holding connections open too long if i am doing other stuff aswell in the controllers.

Is that approach enought to not risking holding too many connections open or should i be doing something more like the example method below? 

   public void Add<T>(T item) where T : class, new()
   {
       using (var mongo = Mongo.Create("connString"))
       {
         mongo.GetCollection<T>().Insert(item); 
       }
   }

Another follow up question is:

Are opening and closing MongoDB connections through Norm "expensive" operations?

Kimpo
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  • Norm is hardly being maintained anymore, if you want LINQ support go with official mongo driver with FluentMongo on top of it. – Zaid Masud Feb 07 '12 at 13:37
  • Beside this question of opening and closing connections on the code, I had issues with the internet provider closing connections, then my code having EndOfStreamException. I solved it by using settings.MaxConnectionIdleTime = TimeSpan.FromSeconds(30); https://stackoverflow.com/a/44606284/194717 – Tony Jun 17 '17 at 22:12

2 Answers2

11

I would leave the connection open as re-creating the connection is costly. Mongo is fine with lots of connections, open for a long time. What you ideally should do is to share the connection with all parts of your application as a persistent connection. The C# driver should be clever enough to do this itself, so that it does not create too many connections, as internally it uses "connection pooling" that makes it even re-use connections. The docs say: "The connections to the server are handled automatically behind the scenes (a connection pool is used to increase efficiency)."

cheers, Derick

Derick
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    Agreed. In fact, you don't even really need to write a MongoSession class — storing a MongoServer instance in application scope would be appropriate. You should almost certainly call Disconnect() on this instance only once, when the MVC application closes. – Sean Reilly Feb 07 '12 at 12:02
  • @Sean Thanks for the tip on when to close connections. – Akshat Jiwan Sharma Oct 13 '12 at 15:49
2

You Do NOT Need to Call Connect or Disconnect

The C# driver has a connection pool to use connections to the server efficiently. There is no need to call Connect or Disconnect; just let the driver take care of the connections (calling Connect is harmless, but calling Disconnect is bad because it closes all the connections in the connection pool).

http://docs.mongodb.org/ecosystem/tutorial/getting-started-with-csharp-driver/

Robson
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