Those who install and create a database running in the Oracle release 12.2.0.3 launched by Oracle Corporation in February 2019 might get surprised about the unknown hash services shown in the listener due to the PDB databases. I must say that my first thought was, “What?????”. Write in the comments how was yours. My first information is: don’t freak out! This service was introduced by the Oracle Database release 12cR2 due to the possibility of creating a PDB as a Proxy PDB. Thus, what you can see of new in…