Even if your changes are idempotent, you still will need transaction.
I have experienced exactly the same performance problem with a Spring / Hibernate batch process. Note that this has nothing to do with Spring Roo or even Spring - it is due to the workings of Hibernate / JPA.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.