Why do you think it is inefficient? Have you measured the time it takes and noticed that it is too slow for your use case?
If you plan to update thousands of entities in the same way, you should rather consider using a HQL DML statement to do the update e.g. update MyEntity e set e.myAttribute = '' where ...
There is not. When using JDBC batching, the network latency effect of sending multiple commands is reduced, but that’s the best that you can do with dirty checking.