I have read around the forums for some time now, but can't find a good answer to this question.

If I have a webapp deployed as two war files in a tomcat (or similar) servlet container. These two war files access the same (mysql innodb) database, and usage of tables overlap. Is it possible for one web application to be aware of transactions started in the other web application, and vice-versa?

I have read that the hibernate mappings must be bundled with each webapp that is deployed. Will this stop me from making the webapps aware of each others transactions? (As each webapp uses its own cache and JTA?)

We are considering to use Hibernate in a heavy load environment, and would like to split our application into different webapps on the same tomcat instance - for ease-of-maintainability and upgrades.

Anyone have som ideas or thoughts about this?

Regards,
Olve

Do you expect a webapp to call another webapp ?
Cascaded calls through HTTP cannot be Transactional.

Sorry about the crosspost, I didn't get any answers in beginners section, and I started to doubt this was a beginners problem.

What I want to do is having two web-applications, where each other knows about the other webapp's transactions.

As far as I understand, Hibernate can keep track of the transactions using JTA, but only within the web-application that started it. Also lock information are only kept in the cache (oposed to using the native db-vendors locking mechanism)?

If rows are locked by a transaction in webappA, and another user uses webappB trying to change the same rows, how can I make hibernate react to that situation?

Can I do this by deploying the hibernate DAO and Managers by itself, and have webappA and B lookup up the specific managers through JNDI? Maybe using the Spring framework. Perhaps putting only the session object in the JNDI database?

Or is it possible at all? Maybe using a clustered cache? I hope for a simpler solution, as the webapps will be located on the same physical machine.. I am starting to think that I should rethink the architecture of this webapp..


Sorry if I am a bit vague in my explanations, as I am quite new to hibernate. We are considering to switch from JBoss and cmp2.0 to tomcat and hibernate. So I am exploring the possibilities. I like what I see, but I am trying to get a hold of the limitations of Hibernate - to see what it can and can't do..


Thanks for the help so far,

JTA is completly delegated to you JTA TM, so Hibernate is only limited to it.
Hibernate *do not ever* put pessimistic lock information in the middle tier.
Only optimistic locking is send through layers, but there is no relationship.


Read the optimistic locking chapter, it is not related to Db Transaction


I can't really understand what you've in mind. Can you do that with a plain old JDBC DAO ? If yes, you can do it with Hibernate.


You"re mixing differents issues. Yes, you should reconsider your architecture AFAIK