JPAContainer still querying each row

I’m trying to use JPAContainer with EJB entity providers, but loading a table takes really too much time.
As I can see JPAContainer generates a series of queries for the IDs of each entry and after that a series of queries for each row in the table. After the selects complete, the caching handles the further loads, but the first load is very slow this way.

Is there any way to force JPAContainer to use a “one query per table”, or at least some kind of batched query?
I’ve tried with CachingLocalEntityProvider and CachingMutableEntityProvider as well, but the result is the same.

I am facing same issue .I have used JPA in Combobox-but it is taking a lot time to fetch data in the dropdown as a result the performance is slow and if i scroll down the dropdown to select the intended country its taking a lot of time to load data!
My purpose was to fetch country list in the dropdown using JPAContainer of Country.
My code is as follows
custnationalityBox.setConverter(new SingleSelectConverter(custnationalityBox));
custnationalityBox.addListener(new ValueChangeListener() {}

Kindly suggest any way to do more quickly