I don't think there will be any performance problem using CMP. To quote Ed Roman in Mastering
EJB 2, "CMP entity beans, if tuned properly, are much higher performing than BMP entity beans."
IMHO there are 2 reasons that alternative approaches such as Hibernate and JDO are becoming more popular:
- A growing realization that the services provided by EJBs (sophisticated transactional support, security etc) are not always needed. See for example Bruce Tate's recent book "Better, Faster Lighter Java".
- The programming model for EJBs generally and entity beans in particular is complicated, and difficult for less experienced developers. This is being addressed in EJB 3.0.
My 2 cents worth :-)
Paul