Various Oracle University course materials use the phrase "fast intra-CDB db link" to describe database links between pluggable containers residing in the same CDB. They also state that "...because the link communication does not leave the instance, the link is very fast". I can find no other reference to this "fast intra-CDB db link" concept and my own tests appear to show that database links between containers work in exactly the same way that they do in a non-CDB environment: contacting the listener to estabish a session, and then sending data each way over TCP. So just the same as a loop-back db link in a non-CDB environment.
Can anyone point me to any doc describing how this "fast intra-CDB db link" works? Or confirm that it does or does not exist?
Thank you for any insight.