[hibernate-dev] Connection release mode and Session.connection() deprecation

[Scott Marlow]

If we have a bean (topbean) invoking another bean (childbean) method 
that needs a new JTA transaction 
(http://docs.oracle.com/javaee/6/api/javax/ejb/TransactionAttributeType.html#REQUIRES_NEW), 
we will want to use separate database connections for the two beans.

I think that this would only be a requirement if a (container managed) 
extended persistence context is used since two separate Hibernate 
sessions would be used if the persistence context is transaction scoped.

If we are in a JTA transaction, I think that associating the connection 
with the transaction could be an alternative to associating the 
connection with the session.

On 10/15/2012 12:30 PM, Steve Ebersole wrote:
> Was thinking some more today about the deprecation of Session.connection()
>
> The reason we deprecated it was that we need a way to scope access to
> the Connection because Session may have to release it due to "release
> mode".  The back story here is that we added "connection release mode"
> as a way to fix an earlier problem using Hibernate in certain
> container-managed-transaction scenarios involving nested bean calls
> where they both used the same Session but the nested bean forced the
> session to obtain a Connection first.  Hibernate tries to delay
> obtaining the JDBC Connection until needed.  However, in the stated
> scenario that leads to a situation where the container managing the
> transaction sees a Connection "leaking" from the nested bean call since
> it was the one that forced the Connection to be obtained from the
> DataSource.  The solution to this back then was to have Hibernate
> release the Connection whenever it was done using it for the moment in
> JTA cases.  In retrospect, I think a much cleaner solution to the above
> situation is to force the Session to obtain the Connection up front
> rather than this obtain/release as-needed cycle.
>
> So as one more attempt to save Session.connection() from going away, I
> wanted to propose that we drop the notion of "release mode" in favor of
> simply saying whether or not to aggressively acquire the Connection when
> the Session starts.  Then all of the concerns that made deprecating and
> planning on removing  Session.connection() are no longer there.
>
> WDYT?
>
>