DbGenerator.runGenerator takes a DataSource as a parameter and manages its connection internally. So logically it is responsible for connection commit when the operation is finished. It doesn't do it, causing issues like . The use case is when the DataSource sets autocommit to false and rolls back connections returned to the pool, hence undoing the work done by DbGenerator.
The fix is simple (commit the connection at the end if no errors happened; rollback otherwise), but will need to be tested across all DBs.