Question

I have a n-tier application based on pretty classic different layers: User Interface, Services (WCF), Business Logic and Data Access.

Database (Sql Server) is obviously quered throught Entity Framework, the problem is basically that every call starts from user interface and go throught all the layers, but doing that I need to create a new ObjectContext each time for every operation and that makes performance very bad because every time I need to reload metadata and recompile the query.

The most suggested pattern it would be the one below and it is what I’m actually doing: creating and passing the new context throught business layer methods each time the service receives a call

 public BusinessObject GetQuery(){     
   using (MyObjectContext context = new MyObjectContext()){ 
      //..do something  }    }

For easy query I don’t see any particular dealy and it works fine but for complex and heavy query it makes a 2 seconds query to keep going for like 15 seconds each call.

I could set the ObjectContext static and it would solve the performance issue but it appears to be not suggested by anyone, also because I won’t be able to access the context at the same time from different thread and multiple calls raise an exception. I could make it thread-safe but mantain the same ObjectContext for long time makes it bigger and bigger (and slower) because the reference it imports each query it execute a query.

The architecture I have I think it is the most common so what is the best and known way to implement and use ObjectContext?

Thank you,
Marco

Answer 1

In a Web context, it’s best to use a stateless approach and create an ObjectContext for each request.

The cost of ObjectContext construction are minimal. The metadata is loaded from a global cache so only the first call will have to load it.

Static is definitely not a good idea. The ObjectContext is not thread save and this will lead to problems when using it in a WCF service with multiple calls. Making it thread save will result in less performance and it can cause subtle errors when reusing it in multiple requests.

Check this info: How to decide on a lifetime for your ObjectContext