upgrade from READ to OPTIMISTIC_FORCE_INCREMENT fails

PR: https://github.com/hibernate/hibernate-orm/pull/483

Improving the test, with the above change, sounds good to me, as long as no new failures are introduced.

I've found out what's the problem with failing test, this finally block should be like this:

I think, we should close em2 before we send the signal, because sometimes em2 appears to be opened after the test completion -> releaseUnclosedEntityManagers() is invoked, but in the meantime em2 is closed in the finally block in another thread.

don't know why it failed and now passes, but yes, let's close this

Strong, what does the above error have to do with the change?

I agree that we should fix the other failures, like but
https://ci.jboss.org/hudson/job/hibernate-core-master-matrix/117/database=oracle11gR1RAC,jdk=java16_default,label=hibernate/testReport/junit/org.hibernate.ejb.test.lock/LockTest/testContendedPessimisticReadLockTimeout/

But, the upgrade test appears to be passing:
https://ci.jboss.org/hudson/job/hibernate-core-master-matrix/117/database=oracle11gR2RAC,jdk=java16_default,label=hibernate/testReport/org.hibernate.ejb.test.lock/UpgradeLockTest/

Also, the mysql test didn't have failures.

The Oracle failures should be reported with a new jira, I think.

I'll close this jira and if you agree, can you create a new jira for the failures that you are concerned with.