ORA-14693: The MAX_STRING_SIZE parameter must be EXTENDED.

https://docs.oracle.com/en/database/oracle/oracle-database/19/spmsu/enabling-the-new-extended-data-type-capability.html

SQL>
ALTER PLUGGABLE DATABASE ORCL19 OPEN UPGRADE;

SQL> ALTER PLUGGABLE DATABASE ORCL19 OPEN UPGRADE
*
ERROR at line 1:
ORA-14693: The MAX_STRING_SIZE parameter must be EXTENDED.
Help: https://docs.oracle.com/error-help/db/ora-14693/

SQL> SHOW PARAMETER max_string_size;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
max_string_size                      string      STANDARD


SQL> SHUTDOWN IMMEDIATE;
Database closed.
Database dismounted.
ORACLE instance shut down.



SQL> ALTER SYSTEM SET max_string_size=EXTENDED SCOPE=SPFILE;
ALTER SYSTEM SET max_string_size=EXTENDED SCOPE=SPFILE
ORA-01034: The Oracle instance is not available for use. Start the instance.
Process ID: 0
Session ID: 0 Serial number: 0
Help: https://docs.oracle.com/error-help/db/ora-01034/



SQL> STARTUP UPGRADE;
ORACLE instance started.
Total System Global Area 6120784560 bytes
Fixed Size                  5022384 bytes
Variable Size            1124073472 bytes
Database Buffers         4982833152 bytes
Redo Buffers                8855552 bytes
Database mounted.
Database opened.
System altered.




SQL> @?/rdbms/admin/utl32k.sql
Session altered.
DOC>#######################################################################
DOC>   The following statement will cause an "ORA-01722: invalid number"
DOC>   error if the database has not been opened for UPGRADE.
DOC>
DOC>   Perform a "SHUTDOWN ABORT"  and
DOC>   restart using UPGRADE.
DOC>#
no rows selected
DOC>   error if the database does not have compatible >= 12.0.0
DOC>   Set compatible >= 12.0.0 and retry.
PL/SQL procedure successfully completed.
0 rows updated.
Commit complete.
Table created.
Table truncated.
0 rows created.
STARTTIME
--------------------------------------------------------------------------------
03/02/2026 13:55:45.089424000
No errors.
DOC>   error if we encountered an error while modifying a column to
DOC>   account for data type length change as a result of enabling or
DOC>   disabling 32k types.
DOC>   Contact Oracle support for assistance.
Package altered.
ORA-00603: ORACLE server session terminated by irrecoverable error
ORA-01092: ORACLE instance terminated. Disconnection forced
ORA-01013: User requested cancel of current operation.
Process ID: 5168
Session ID: 625 Serial number: 8539
Help: https://docs.oracle.com/error-help/db/ora-00603/


SQL> SHUTDOWN ABORT;
ORA-24324: service handle not initialized
Help: https://docs.oracle.com/error-help/db/ora-24324/
ORA-01041: internal error. hostdef extension doesn't exist

SQL> Disconnected from Oracle AI Database 26ai Enterprise Edition Release 23.26.1.0.0 - Production
Version 23.26.1.0.0

[oracle@centos9 admin]$ sqlplus / as sysdba
SQL*Plus: Release 23.26.1.0.0 - Production on Mon Mar 2 13:58:56 2026
Copyright (c) 1982, 2025, Oracle.  All rights reserved.
Connected to an idle instance.


SQL> starup ;
SP2-0042: unknown command "starup " - rest of line ignored.
Help: https://docs.oracle.com/error-help/db/sp2-0042/

SQL> startup ;

SQL> show parameter max_string_size
max_string_size                      string      EXTENDED