Retrieving Entity Performance in JPA

Question

Below is the code I used to retrieve Profile entity:

    EntityManager em = EMF.get().createEntityManager();
    return em.find(Profile.class, email);

If Profile have a lot of properties and some are List or Set and if I only need 3 String properties (eg, Last Name, First Name, birthday), is it okay to retrieve using the above code or I have to write a query retrieving only those 3 properties?

By the way, the application is run under Google App Engine.

Thanks

Answer 1

I think AppEngine doesn't allow you to select only 3 properties from an entity. All entities stored in AppEngine will be considered as a unit that you can't spit it up.

However, if the Profile entity has some child-entities, then it would be better not to fetch them.