alter session set container delays serveroutput

alter session set container = cdb$root;
set serveroutput on

exec dbms_output.put_line( 'dbms output is on in cdb$root ' || sys_context ('userenv', 'con_name'))

alter session set container = kona;
exec dbms_output.put_line( 'dbms output is OFF in pdb kona ' || sys_context ('userenv', 'con_name'))

set serveroutput on
exec dbms_output.put_line( 'dbms output is on in pdb kona ' || sys_context ('userenv', 'con_name'))

alter session set container = cdb$root;
exec dbms_output.put_line( 'dbms output remains on in cdb$root ' || sys_context ('userenv', 'con_name'))

alter session set container = kona;
set serveroutput off
exec dbms_output.put_line( 'kona. output discarded ' || sys_context ('userenv', 'con_name'))
alter session set container = cdb$root;
exec dbms_output.put_line( 'cdb$root. display delayed ' || sys_context ('userenv', 'con_name'))

set serveroutput on
prompt serveroutput is on but you don't see the output yet
prompt The delayed output will appear before the "Session altered." feedback
alter session set container = cdb$root;

quit

output is:


Session altered.

dbms output is on in cdb$root CDB$ROOT

PL/SQL procedure successfully completed.


Session altered.


PL/SQL procedure successfully completed.

dbms output is on in pdb kona KONA

PL/SQL procedure successfully completed.


Session altered.

dbms output remains on in cdb$root CDB$ROOT

PL/SQL procedure successfully completed.


Session altered.


PL/SQL procedure successfully completed.


Session altered.


PL/SQL procedure successfully completed.

serveroutput is on but you don't see the output yet
The delayed output will appear before the "Session altered." feedback
cdb$root. display delayed CDB$ROOT

Session altered.