I noticed when doing some performance testing of my code that my usage of TransactionScope resulted in huge memory usage that just grew, never shrank, even after GC. At first I thought it was the SqlClient but in the end I boiled it down to the TransactionScope class and the TransactionScopeAsyncFlowOption.Enabled option which is used to support async/await with TransactionScope. I use this option everywhere to allow for SQL transactions to flow correctly with async code.

I am not entirely sure if it's me who is misunderstanding the debugger's output but running the code below leaves me with multi-gigabyte memory usage according to both the debugger and the task manager. It looks like a memory leak to me but I'm not an expert in these things, so I thought I'd report it.

There are two versions below, the first one with TransactionScopeAsyncFlowOption.Enabled grows its memory usage constantly and the other doesn't.

using System.Transactions;

namespace TestTrxScope
{
    class Program
    {
        static void Main(string[] args)
        {
            while(true)
            {
                using(var scope = CreateTransactionScope())
                {
                    scope.Complete();
                }
            }
        }

        public static TransactionScope CreateTransactionScope()
        {
            //Memory grows constantly
            return new TransactionScope(TransactionScopeAsyncFlowOption.Enabled);

            //This version doesn't constantly grow in memory usage
            //return new TransactionScope();
        }
    }
}