Show hidden parameters

SET LINESIZE 145
SET PAGESIZE 9999
SET VERIFY   off

COLUMN ksppinm   FORMAT A42   HEAD 'Parameter Name'
COLUMN ksppstvl  FORMAT A39   HEAD 'Value'
COLUMN ksppdesc  FORMAT A60   HEAD 'Description'    TRUNC


SELECT
    ksppinm
  , ksppstvl
  , ksppdesc
FROM
    x$ksppi x
  , x$ksppcv y
WHERE
      x.indx = y.indx 
  AND TRANSLATE(ksppinm,'_','#') like '#%'
/

Get 1 hidden parameter

select a.ksppinm name, b.ksppstvl value,
b.ksppstdf deflt, decode
(a.ksppity, 1,
'boolean', 2,
'string', 3,
'number', 4,
'file', a.ksppity) type,
a.ksppdesc description
from sys.x$ksppi a, sys.x$ksppcv b
where a.indx = b.indx and
a.ksppinm like '\_%' escape '\'
and a.ksppinm like UPPER('%&PARAM_NAME%')
order by name;

DB parameter

set linesize 230
set pagesize 9999
COLUMN name      		FORMAT a40		  HEADING 'Name'
COLUMN value       		FORMAT a80		  HEADING 'Value'
COLUMN display_value	FORMAT a30		  HEADING 'Display Value'

select name, value, display_value, ISDEFAULT, ISMODIFIED, ISSES_MODIFIABLE, ISSYS_MODIFIABLE, ISADJUSTED from v$parameter 
	where upper(name) like upper('%&PARAM_NAME%')
	order by name
/