Downside of using TransactionScope RequiresNew

Question

I want to understand what is the trade-of/downside of using TransactionScopeOption.RequiresNew on EntityFramework (w/ Sql Server 2008

Answer 1

You should use Required not RequiresNew. RequiresNew means every operation will use a new transaction, even if there is an encompassing already existing transaction scope. This will certainly lead to deadlocks. Even with Required there is another serious problem with TransactionScope, namely that it creates by default a Serializable transaction, which is a horribly bad choice and yet another shortcut to deadlock hell and no scalability. See using new TransactionScope() Considered Harmful. You should always create a transaction scope with the explicit TransactionOption setting the isolation level to ReadCommitted, which a much much much more sane isolation level:

using(TransactionScope scope = new TransactionScope(
    TransactionScopeOption.Required,
    new TransactionOptions {
       IsolationLevel = IsolationLevel.ReadCommitted}))
{
   /// do work here
   ...
   scope.Complete();
}

Answer 2

I just wanted to add here that in a couple certain cases the method i've written is inside a parent transaction scope that may or may not be closed with scope.Complete() in these cases I didn't want to be dependent on the parent transaction so we needed to set RequiresNew.

In general though I agree it's not necessary and should use read committed.

http://msdn.microsoft.com/en-us/library/ms172152(v=vs.90).aspx