Which SPIs would change? JdbcCoordinator and TransactionCoordinator? How do we get into the situation of having 2 sessions share a JDBC connection? Does this impact both JPA and Hibernate native based applications?
On 03/16/2012 09:27 AM, Steve Ebersole wrote: > Reference https://hibernate.onjira.com/browse/HHH-7020 and > https://hibernate.onjira.com/browse/HHH-7090... > > Essentially, having 2 sessions share a JDBC connection is currently > broken. Adam, Lukasz and I discussed this on the mailing list a few > months ago and Shawn has been helping me investigating the last few > days. The solution end solution is to have the 2 sessions share both > the TransactionCoordinator and LogicalConnection, but use separate > JdbcCoordinators. > > We could get away with them sharing a JdbcCoordinator as well, but that > opens up (slight) potential concurrency issues if the 2 sessions are > used concurrently. The concurrency issues here are not on the same > level as those if using a session concurrently. Mainly JdbcCoordinator > manages the "current JDBC batch" if the session is using JDBC statement > batching. Concurrent access could mean batch circumvention (aka, 1 > statement executed in the batch instead of the batch size) if both > sessions are performing writes concurrently. > > All the above is a bit specific, but the ultimate question/decision here > is that in order to not reuse JdbcCoordinators requires *major* SPI > changes. Basically we need to invert the relationship between > JdbcCoordinator and TransactionCoordinator. Currently Session holds a > TransactionCoordinator and that TransactionCoordinator is responsible > for managing the JdbcCoordinator. The "proper" change would require > that instead Session hold a JdbcCoordinator which is responsible for > managing a TransactionCoordinator. > > A consideration here is that these are SPIs and should not really be > changing between point releases. But another thing to consider is that > these particular SPIs were added in 4.0, so they are relatively new, and > that, in this particular case at least, they are just plain wrong. > > What do y'all think between these 2 options? > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
