Reference:
Practical Oracle E-Business Suite (book)
Pool sizes can be tuned for JDBC connections, stateless session Enterprise Java Beans (EJBs ), and
Message Driven Beans (MDBs ). Setting the pool sizes to the optimal values may increase the performance
of FMW, as it will avoid the delays created by the pooling activities. In this manner, as for the JDBC data
sources, you can increase the Maximum Capacity of Connection Pools setting to handle the probable
peaks in the concurrent connections, and you can also configure the connection pool to initialize all its
connections at server startup to avoid connection creation delays.