OnPost events run before a commit

问题

Say I have some standard NHibernate code like this, which writes to an SQL database:

using (var session = SessionFactory.OpenSession())
{
  using (var tx = session.BeginTransaction())
  {
      var customer = session.Get<Customer>(id);
      customer.Property1 = "new value";
      customer.Property2 = "new value";
      tx.Commit();
  }
}

I am trying to create a copy table for the Customer (in a NoSQL database). Therefore when the code above runs the following event handler runs:

public void OnPostUpdate(PostUpdateEvent postUpdateEvent)
        {
            if (postDeleteEvent.Entity.GetType() == typeof(Customer)) 
            {
                var customer = (Customer)postUpdateEvent.Entity;
                customerCopyRepository.Update(customer);
            }
        }

If I was to change the first code fragment to an insert, then this would run:

 public void OnPostInsert(PostInsertEvent postInsertEvent)
        {
            if (postInsertEvent.Entity.GetType() == typeof(Customer))  
            {
                var customer = (Customer)postInsertEvent.Entity;
                customerCopyRepository.Insert(customer);
            }
        }

and when a delete occurs this runs:

public void OnPostDelete(PostDeleteEvent postDeleteEvent)
        {
            if (postDeleteEvent.Entity.GetType() == typeof(Customer)) 
            {
                var customer = (Customer)postDeleteEvent.Entity;
                customerCopyRepository.Delete(customer.Id);
            }
        }

CustomerCopyRepository is injected into the class constructor.

This is working very nicely. The only problem I have is that each of the events above seem to run before the data is committed to the database. Therefore the following scenario could occur:

1) Write Customer to NoSQL database.

2) Customer is not written to SQL database(because of an SQL error).

Is there any way I can prevent this scenario?

回答1:

I have exactly the same scenario (Sync with ElasticSearch) and I ended up by using the RegisterSynchronization method:

private void Sync(IPostDatabaseOperationEventArgs e)
{
    e.Session.Transaction.RegisterSynchronization(new AfterTransactionCompletes(success =>
    {
        if (!success)
            return;

        // Do your stuff
    }));
}

来源：https://stackoverflow.com/questions/50235881/onpost-events-run-before-a-commit

标签

nhibernate