10.1.2 Performance Implications

All run-time access to the Interface Repository is via the Interface Repository server. Because there is considerable overhead in making requests of a remote server application, designers need to be aware of this. For example, consider the interaction required to use an object reference to obtain the necessary information to make a DII invocation on the object reference. The steps are as follows:

1. The client application invokes the _get_interface operation on the CORBA::Object to get the InterfaceDef object associated with the object in question. This causes a message to be sent to the ORB that created the object reference.
2. The ORB returns the InterfaceDef object to the client.
3. The client invokes one or more _is_a operations on the object to determine what type of interface is supported by the object.
4. After the client has identified the interface, it invokes the describe_interface operation on the Interface object to get a full description of the interface (for example, version number, operations, attributes, and parameters). This causes a message to be sent to the Interface Repository, and a reply is returned.
5. The client is now ready to construct a DII request.