Re: [keycloak-dev] Hybrid store committed

On 8.7.2014 16:12, Stian Thorgersen wrote: > If we used beans and container managed transactions then it might do > that. It may also just create multiple transactions and do a 2PC. But, > we don't, we start/commit our own transactions in Hibernate, and at > the moment we explicitly create multiple transactions. > > Before I'll start this I'll check what happens. I'm sure I can > relatively easily add some debug statements for when jdbc connections > and transactions are created. > > It may also be better for us to create a UserTransaction and have the > EM's enlist with that, instead of managing our own. That way we would > get proper 2PC when its supported. That may be a bit overkill though, > as I don't think we'd often want to update multiple databases at the > same time. +1 to use UserTransaction and JTA. I think earlier or later we may need to support 2PC anyway. Also AFAIK with JTA the jdbc connection is created "lazily" with Hibernate. In details if "hibernate.current_session_context_class" is "thread" (which is by default) then new JDBC connection is always opened when calling "hibernateSession.getTransaction().begin()" . But when "hibernate.current_session_context_class" is "jta" it retrieves JDBC connection lazily when DB call is needed by Hibernate. At least, last time I used this, it behaved this way. I used plain hibernate API though (not JPA EntityManager), but I don't think that the behaviour is different with JPA. With respect to the fact that we have caching layer, there may be many HTTP requests, which won't need to open JDBC connection, which might be nice performance gain IMO.