Re: [Springframework-developer] Nested transactions

[Rod J. <rod...@in...>]

Thomas

> Any way you can get this to work in a managed environment with JTA :-)

Not without:

- having all savepoint-capable resources (not unlikely, for example, if
you're using DB2 and Oracle, say)
- being able to get at the underlying API of the transaction manager, rather
than purely via JTA. This is conceivable, but won't make the 1.1 timeframe.
- not having an ORM tool like Hibernate, which doesn't understand
savepoints, involved in the transactions. Otherwise its cache will be
unaware of the reversion to a savepoint. Of course if the ORM tool is only
used for data that isn't modified and reverted that's fine.

I think these transaction enhancements are an important feature, although
it's important to understand that they work only in certain scenarios.
Basically we're taking a different approach to JTA (but of course without
sacrificing our excellent support for JTA).

The JTA philosophy is that "nested transactions are not supported by all
resource managers, so forget about them, or use the resource manager's local
transaction API directly."

We're saying: "here's a feature that works with some resource managers in
certain situations. We provide access to it."

This is an important distinction. For example, I have a client who have a
huge Oracle database. They need to do very high transaction volumes, but
they will never use another transactional resources. Yet some of the
transaction processing they need to do is complex and requires nested
transactions, not PROPAGATION_NEW. It's hard to work around that; they've
paid for the database, and should be able to use its features without
reverting to direct JDBC transaction management, loss of declarative
transactions etc. Those parts of their tx processing use JDBC, rather than
any ORM solution, to absolutely minimize overhead. This is what led to my
desire for this feature: I can see a significant business value, in a
certain range of situations.

Hopefully, over time, the range of resources supporting sophisticated tx
management concepts will grow.

Rgds
Rod