using (var tx = new TransactionScope())
using (var s = sessions.OpenSession())
using(s.BeginTransaction()) {
new ForceEscalationToDistributedTx();
s.Delete(s.Get<Person>(id));
s.Transaction.Commit();
tx.Complete();
}
this work ?
2009/3/23 Ayende Rahien <[email protected]>
> Hi guys
> I am still working on the DTC issues with NH that I detailed in my previous
> post.
> In particular, all those issues comes up mostly because we didn't test the
> DTC in true distributed escalation scenario.
> Now that I am doing this, I am finding a lot of problems.
>
> Attached is a file that demonstrate the source of a lot of them.
> The second file is showing the proposed solution, using:
> EnlistDuringPrepareRequired
>
> But first, I need to explain how NH's DTC support works.
> If we use an NH session within the context of a TransactionScope, we are
> going to get enlist the session in the DTC as volatile resource
> We make the assumption that the underlying ADO.Net provider is supporting
> DTC correctly (not always a valid assumption, see postgres' issues about
> this, but there isn't much we can do about this) and registering itself as
> the durable resource.
> Now, this is the failing test:
>
> using (var tx = new TransactionScope())
> using (var s = sessions.OpenSession())
> {
> new ForceEscalationToDistributedTx();
>
> s.Delete(s.Get<Person>(id));
>
> tx.Complete();
> }
>
> The sequence of event is:
> 1/ load object from db
> 2/ register object for deletion
> 3/ complete transaction
> 4/ dispose session
> 5/ dispose transaction
> 5.1/ call session.Prepare()
> 5.2/ here we flush the changes to the database
>
> the problem is in 5.2, at this point, _if_ we are in escalated transaction,
> and if we are using this approach, we cannot call to the DB again.
> That is ecause at this point we are outside the scope of the transaction -
> first file shows this.
> As I can see this, we have a few options here:
> 1/ use EnlistDuringPrepareRequired, which is my temporary solution to this.
> 2/ move the actual flush behavior into the dispose (only on DTC sessions).
>
> The cleanest solution by far is 1, but it means that e cannot use the
> single phase enlistment optimization, unfortunately.
> I would like to solicit some additional opinions about that.
>
>
>
--
Fabio Maulo
