Gather Fixed Objects Stats in PDBs as well?

Yesterday I received an interesting customer question: “Do we have to gather fixed objects stats inside a PDB as well or only in the CDB$ROOT?” The customer told me he couldn’t find anything in the documentation. Neither could I. And I did check also the usual suspects this morning “Best Practices for Gathering Statistics” – but it does not say anything about PDBs and CDBs. Therefore I did a short test: Create a PDB in my Oracle 12.1.0.2 CDB: SQL> create pluggable database PDB3 admin user adm identified by adm file_name_convert=( ‘/u02/oradata/CDB1/pdbseed’, ‘/u02/oradata/CDB1/pdb3’); Open the PDB: SQL> alter pluggable database…