RE: [Springframework-developer] Nested transactions

[Alef A. <al...@jt...>]

Good stuff Juergen.

It would be nice to have those kind of features tested regularly. =
Unfortunately I still haven't managed to setup an Oracle instance on the =
Linux box we've got here. I've been running into problems with Oracle =
and the distro we're using (RedHat ES 3) several times.

Alef


> -----Original Message-----
> From: spr...@li...
> [mailto:spr...@li...] On =
Behalf
> Of j=FCrgen h=F6ller [werk3AT]
> Sent: Saturday, June 19, 2004 12:16 PM
> To: spr...@li...
> Subject: [Springframework-developer] Nested transactions
>=20
> Thomas, Alef, Colin, everybody,
>=20
> Motivated by Rod, I've added support for nested transactions to our
> transaction infrastructure, via the new propagation behavior
> PROPAGATION_NESTED. The transaction manager needs to open a true =
nested
> transaction which can be rolled back individually while still being =
able
> to continue with the surrounding transaction.
>=20
> Furthermore, application code can also use custom savepoints: The
> TransactionStatus interface now has a SavepointManager superinterface,
> which provides generic means to create savepoints and roll back to =
them.
> This is only intended for advanced needs where the declarative nested
> transaction model is not sufficient.
>=20
> DataSourceTransactionManager implements nested transaction support via
> JDBC 3.0 Savepoints: basically, create a Savepoint on nested =
transaction
> begin, release it on nested transaction commit, roll back to it on =
nested
> transaction rollback. Of course, DataSourceTransactionManager is still
> compatible with JDBC 2.0 if not using nested transactions.
>=20
> HibernateTransactionManager and JdoTransactionManager offer support =
for
> JDBC 3.0 Savepoints too, but it's deactivated by default there: =
Savepoints
> are just able to roll back the underlying JDBC Connection, not the =
Session
> respectively PersistenceManager with its object cache. Savepoints are
> still useful for JDBC access code that participates in a Hibernate/JDO
> transaction, though, when used with care.
>=20
> All of this is already fully covered by unit tests. Unfortunately, I =
don't
> have a database with savepoint support available here, i.e. no Oracle; =
so
> I've just been able to test that it fails nicely against MySQL (on JDK =
1.4
> and 1.3). Thomas, do you have a chance to test this against a live
> database?
>=20
> An example for how PROPAGATION_NESTED is supposed to work. Note that =
the
> nested transaction sets the rollback-only flag: This should just cause =
a
> rollback of the second update statement but still allow the =
surrounding
> transaction to commit the first update statement.
>=20
>   DataSource ds =3D ...;
>   final PlatformTransactionManager tm =3D new
> DataSourceTransactionManager(ds);
>   final JdbcTemplate jt =3D new JdbcTemplate(ds);
>=20
>   TransactionTemplate tt1 =3D new TransactionTemplate(tm);
>   =
tt1.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
>   tt1.execute(new TransactionCallbackWithoutResult() {
>     protected void doInTransactionWithoutResult(TransactionStatus =
status)
> {
>       jt.update("first update statement");
>=20
>       TransactionTemplate tt1 =3D new TransactionTemplate(tm);
>=20
> tt1.setPropagationBehavior(TransactionDefinition.PROPAGATION_NESTED);
>       tt1.execute(new TransactionCallbackWithoutResult() {
>         protected void doInTransactionWithoutResult(TransactionStatus
> status) {
>           jt.update("second update statement");
>           status.setRollbackOnly();
>         }
>       });
>     }
>   });
>=20
> An example for the same effect via manual savepoint management:
>=20
>   TransactionTemplate tt1 =3D new TransactionTemplate(tm);
>   =
tt1.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
>   tt1.execute(new TransactionCallbackWithoutResult() {
>     protected void doInTransactionWithoutResult(TransactionStatus =
status)
> {
>       jt.update("first update statement");
>=20
>       Object savepoint =3D status.createSavepoint();
>       jt.update("second update statement");
>       status.rollbackToSavepoint(savepoint);
>=20
>     }
>   });
>=20
> Juergen
>=20
>=20
>=20
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>=20
>=20