ORACLE 19C pdb修改的参数保存在哪个数据字典中？

PDB关闭后，保存在：
pdb_spfile$中。
下面举例：
在PDB1中修改 ddl_lock_timeout=10
SQL> alter session set container=pdb1;
Session altered.
SQL> show parameter ddl_
NAME TYPE VALUE

------------------------------------ ----------- ------------------------------
ddl_lock_timeout integer 0
enable_ddl_logging boolean FALSE
SQL> alter system set ddl_lock_timeout=10;
System altered.
SQL> shutdown immediate;
Pluggable Database closed.
SQL> conn / as sysdba
Connected.
SQL> show con_name
CON_NAME

------------------------------
CDB$ROOT
SQL> select p.name as pdb_name,s.name as parname,VALUE$
from pdb_spfile$ s,v$pdbs p
where s.pdb_uid=p.con_uid
PDB_NAME PARNAME VALUE$

------------------------------ -------------------- --------------------
PDB1 ddl_lock_timeout 10