SQL Azure + Getting an error 'There is already an open DataReader associated with this Command..', even after setting ‘MultipleActiveResultSets=True’

Question

We are facing some issues with the deployed version of our application on cloud.

Our application is an ASP.NET MVC 3 project with ADO .NET Entity Framework.

Acco

Answer 1

You do have to set multipleresultsets=true in connectionsstring and restart.

Removed answer

Edit: This is debated! Check comment beneath... I havent had time to investigate...

I think it is already turned on.

I couldn't find a spot-on source but Faisal Mohamood(Program Manager, Entity Framework) states the following back in 2010: "Needless to say, we will make sure that MARS is automatically turned ON for SQL Azure based apps when we get around to releasing the next update to the product." Found it here: http://blogs.msdn.com/b/adonet/archive/2010/06/09/remember-to-re-enable-mars-in-your-sql-azure-based-ef-apps.aspx

Answer 2

Try assigning MultipleActiveResultSets in code. Is it not read or is is not working?

SqlConnectionStringBuilder.MultipleActiveResultSets

Answer 3

i have the same problem, but i solved MultipleActiveResultSets=True in the connection string from Publish assistant, as irium

Answer 4

We're on the new Azure portal and had this problem as well. MARS worked on all local dev environments, but threw the same nasty exception on Azure. We verified that the connection string in the physical web.config file deployed to Azure contained MultipleActiveResultSets=true; but it didn't seem to be honored by the application. Ultimately what worked was going to the app service instance > settings > data connections, and deleting the data connection of the same name as the one in question in the web.config. My guess is that the one that Azure stores trumps the one in the deployed web.config.

Answer 5

I've just got the same issue. I has tried setting "MultipleActiveResultSets=True" in Web.config connection - no results. Finally I've resolved issue by manually editing Connection string directly at Azure Dashboard for the web site - in "Configure" tab there is "Connection strings" settings where you should manually add the "MultipleActiveResultSets=True;" string. After doing that I've got MARS worked finally.

Answer 6

Alternatively you can add the "MultipleActiveResultSets=true" to your connection string and update the destination web.config when you are using the Publish feature in Visual Studio. Make sure to select "Use this connection string at runtime (update destination web.config)."