Transaction demarcation (SeamPhaseListener)

[sebastiendeg.sebastien.degardin.gmail.com]

Hi there,

I'm trying to provide full conversational support for a GWT application.

It works fine, I only have a question related to trnasaction demarcation.

We do have some kind of a JSF LifeCycle for Request processing.

I do the same as in JSF, I commit or rollback the transaction after invoking the application then re start another one for building the response.

If I don't restart a new transaction, lazy loading still works .(It goes to the database).
So, is there a reason to restart a transaction after the invoka application phase ?

Config is : Seam managed Persistence Context and seam managed transaction.

[gavin.king]

Well, I would say yes, because I think that all data access should happen inside transactions, but I know of other people who disagree with this and believe it is OK to do read-only data access outside of a transaction.

[christian.bauer]

There is no 'outside of a transaction'. What Gavin means is that sometimes it is OK to read data with auto-committed transactions, but if you want to keep your web-application maintainable, you better not do it. The story is different for two-tier clients that access a database server without middle tier: http://www.hibernate.org/Documentation/NonTransactionalDataAccessAndTheAutoCommitMode

[sebastiendeg.sebastien.degardin.gmail.com]

Thanks !

That's right, there is no write expected, but, isolation could be an important issue.

Cheers,