Dapper with .NET Core - injected SqlConnection lifetime/scope

Question

I'm using .NET Core Dependency Injection to instantiate a SqlConnection object during the application startup, which I'm then planning to inject in my repository. This SqlConnection will be used by Dapper to read/write data from the database within my repository implementation. I am going to use async calls with Dapper.

The question is: should I inject the SqlConnection as transient or as a singleton? Considering the fact that I want to use async my thought would be to use transient unless Dapper implements some isolation containers internally and my singleton's scope will still be wrapped within whatever the scope Dapper uses internally.

Are there any recommendations/best practices regarding the lifetime of the SqlConnection object when working with Dapper? Are there any caveats I might be missing?

Thanks in advance.

Answer 1

If you provide SQL connection as singleton you won't be able to serve multiple requests at the same time unless you enable MARS, which also has it's limitations. Best practice is to use transient SQL connection and ensure it is properly disposed.

In my applications I pass custom IDbConnectionFactory to repositories which is used to create connection inside using statement. In this case repository itself can be singleton to reduce allocations on heap.