The following query could be of help to view all the hidden parameter and their default values.

SET LINES 999
SET PAGES 300
COL "PARAMETER" FOR A40 
COL "IS_DEFAULT" FOR A10
COL "SESSION" FOR A10
COL "INSTANCE" FOR A10
COL "IS_SESSION_MODIFIABLE" FOR A21
COL "IS_SYSTEM_MODIFIABLE" FOR A20

SELECT a.KSPPINM "PARAMETER", 
       b.KSPPSTDF "IS_DEFAULT",
       b.KSPPSTVL "SESSION", 
       c.KSPPSTVL "INSTANCE",
       DECODE(BITAND(a.KSPPIFLG/256,1),1,'TRUE','FALSE') IS_SESSION_MODIFIABLE, 
       DECODE(BITAND(a.KSPPIFLG/65536,3),1,'IMMEDIATE',2,'DEFERRED',3,'IMMEDIATE','FALSE') IS_SYSTEM_MODIFIABLE
FROM   X$KSPPI  a,
       X$KSPPCV b,
       X$KSPPSV c
WHERE  a.INDX = b.INDX
AND    a.INDX = c.INDX
AND    a.KSPPINM LIKE '/_%' escape '/'
AND    a.KSPPINM LIKE NVL('%&hidden_parameter%','')
/

To view a specific parameter by its name, for instance, the _hcs_disable_vector_transform

Enter value for hidden_parameter: _hcs_disable_vector_transform

old  13: AND    a.KSPPINM LIKE NVL('%&hidden_parameter%','')
new  13: AND    a.KSPPINM LIKE NVL('%_hcs_disable_vector_transform%','')

PARAMETER                      IS_DEFAULT SESSION    INSTANCE   IS_SE IS_SYSTEM_MODIFIABLE
------------------------------ ---------- ---------- ---------- ----- --------------------
_hcs_disable_vector_transform  TRUE       FALSE      FALSE      TRUE  IMMEDIATE

To list all the hidden parameters just hit Enter

SQL> /
Enter value for hidden_parameter:

PARAMETER                      IS_DEFAULT SESSION    INSTANCE   IS_SE IS_SYSTEM_MODIFIABLE
------------------------------ ---------- ---------- ---------- ----- --------------------
_autotask_min_window           TRUE       15         15         FALSE IMMEDIATE

...

_hcs_enable_mem_trck           TRUE       FALSE      FALSE      TRUE  IMMEDIATE
_hcs_disable_view_merge        TRUE       FALSE      FALSE      TRUE  IMMEDIATE
_reg_cache_status              TRUE       FALSE      FALSE      FALSE FALSE

4956 rows selected.

To view all hidden parameters having the specific word in a name, for instance, the script.

SQL> /
Enter value for hidden_parameter: script

old  13: AND    a.KSPPINM LIKE NVL('%&hidden_parameter%','')
new  13: AND    a.KSPPINM LIKE NVL('%script%','')

PARAMETER                      IS_DEFAULT SESSION    INSTANCE   IS_SE IS_SYSTEM_MODIFIABLE
------------------------------ ---------- ---------- ---------- ----- --------------------
_cdc_subscription_owner        TRUE                             TRUE  FALSE
_oracle_script                 TRUE       FALSE      FALSE      TRUE  FALSE
_pdb_first_script              TRUE       FALSE      FALSE      TRUE  FALSE
_federation_script             TRUE       FALSE      FALSE      TRUE  FALSE
_application_script            TRUE       FALSE      FALSE      TRUE  FALSE
_gwm_autoons_ha_subscription   TRUE                             FALSE IMMEDIATE
_gwm_autoons_rlb_subscription  TRUE                             FALSE IMMEDIATE

7 rows selected.

How To Query And Change The Oracle Hidden Parameters In Oracle 10g and Later (Doc ID 315631.1)

Written At

07 NOV 202119:40

OEL Release

7.9 x64

Database Release

19.12.0.0.0