Performance, scale, risk evaluation hibernate

Business Logic layer under the ORM layer with what, someone recommended hibernate, and some people are negative attitude, so decided to understand first, the following is a few days I read the document after some experience, may be a bit pessimistic.

How big a project can 1,hibernate use?

What's the big, it's hard to say, I think it should be a database table more, the business logic is more complex (table Association complex), and requires high performance bar. Other industries I do not know, telecommunications industry software should be so. As far as I know, such database access (especially frequent transactions) usually need to use the process of saving to solve, not to say that they write Java JDBC, not to mention the use of hibernate to solve. So there must be a problem with the scope of application, hope has been skilled hibernate, and to do a number of projects people give help to solve

2 Hibernate performance will be much better?

A lot of people say hibernate performance is good, but it is some cache function, let us not discuss whether there is such a best practice (hope that some people in the country can put forward excellent practices, or pattern), single from the cache itself, it is not a good, otherwise, There is also no distributed cache. Just like the elders nagging this, nagging that, I think it is good for you, in fact, you do not have to say in your heart more trouble. Hibernate to solve all aspects of performance, and provide all aspects of the characteristics, but these add together is not a good thing

3 Does the DBA approve of using Hibernate in the project?

I'm not a DBA, not even familiar with writing SQL statements, so sometimes when I write DAO I often ask DBA,DBA to find their familiar SQL (rather than HQL) in DAO, which I think is one reason why DBAs don't advocate hibernate. Another reason is that the database itself is a perfect system, regardless of its performance or scalability (I think no one is against my point), so the DBA is convinced that it is best to give the problem to the database. So they don't agree that everything depends on hibernate. This view also wants to understand the Hibernate DBA to give confirmation

The history of EJB makes a lot of people have a skeptical attitude to see Hibernate, the previous EJB how successful, Hibernate is also in the way, so I do not believe that the evaluation, just hope one and can start from practice, so that hibernate can reduce the workload of developers, and reduce the risk of using it.