You may be confusing language features with design pattens; async is syntactic sugar to help you manage background tasks, while asynchronous tasks just mean that you're running two or more threads.
Just because NHibernate doesn't support async doesn't mean that you can't run asynchronously. This is very beneficial to the user because you don't want to freeze the UI while you're performing a (relatively) long-running query to a DB/service, especially if the server is bogged down.
I suppose you could count this as a point of failure, but really just a few areas:
- Exceptions - You'd have this problem on one thread anyway, but you should gracefully handle any database errors that you'd encounter.
- UI Management - You don't want to let the user interact with the UI in such a way as to trigger multiple queries, so you might disable a button, etc.
- Result Handling - When the query is complete, you need to ensure that you marshal the data back to the UI thread. In C# this can be done via
Invoke/BeginInvoke, though whether you're in WinForms or WPF determines the details.
EDIT:
Some sample skeleton code assuming WPF and at least .NET 4.0
Task.Factory.StartNew(() =>
{
using (var client = new dbClient())
{
// Perform query here
this.Dispatcher.BeginInvoke(new Action(() =>
{
// Set data source, etc, i.e.
this.Items = result;
}));
}
}).ContinueWith(ex => Logger.LogException(ex), TaskContinuationOptions.OnlyOnFaulted);
