Re: [Springframework-developer] Hibernate commit/rollback

[<tri...@tr...>]

Juergen,

My understanding is that unless you explicitly call a commit on the JDBC
connection, you should _never_ see any changes in the database.  If you close
the connection without calling rollback or committ, the transaction should roll
back automatically.  I suspect the reason there are changes made to the database
is because the table is non-transactional.

> If I understand correctly, a JDBC driver should behave the same: If a commit
> has failed, rollback does not have to be invoked anymore. Would it actually
> hurt if one still invoked rollback? Would that get ignored with most drivers,
> or would it cause yet another exception, a la "transaction is already rolled
> back" or "no transaction anymore"?

I think the exception is thrown during execute on some statement and not the
actual commit call to the JDBC connection, so at this point the transaction is
still active and a rollback would make sense.  Additional rollback calls on a
JDBC connection should not cause any problems - you are basically rolling back a
new transaction that has not had any work performed.

> I intend to fix the Hibernate transaction issue like this: First invoke flush
> manually and treat it like data access, i.e. just commit if it succeeded,
> else cause an explicit rollback. 

I might be wrong here (have not looked at the code), but my impression is that
the Spring code is not actually managing the transaction - it is delegating to
Hibernate to manage the transaction.  If that is the case, then I would see what
the Hibernate guys think about this and have them add a rollback call if the
flush fails.  In the mean time I would leave it as it is since the transaction
should be rolled back either way barring an explicit commit call on the
connection itself.  What dou you mean by "cause an explicit rollback" - call
rollback on the connection or ask Hibernate to roll back?

> Aren't the semantics of Hibernate's commit
> method a bit odd? Shouldn't it cause a rollback itself if the flush failed?

I think they should cause a rollback if the flush failed, unless there is
another transaction manager involved.

Thomas