Undocumented Parameters in Oracle

 Here is a query to see all the undocumented parameters 

SELECT

  a.ksppinm  "Parameter",

  decode(p.isses_modifiable,'FALSE',NULL,NULL,NULL,b.ksppstvl) "Session",

  c.ksppstvl "Instance",

  decode(p.isses_modifiable,'FALSE','F','TRUE','T') "S",

  decode(p.issys_modifiable,'FALSE','F','TRUE','T','IMMEDIATE','I','DEFERRED','D') "I",

  decode(p.isdefault,'FALSE','F','TRUE','T') "D",

  a.ksppdesc "Description"

FROM x$ksppi a, x$ksppcv b, x$ksppsv c, v$parameter p

WHERE a.indx = b.indx AND a.indx = c.indx

  AND p.name(+) = a.ksppinm

  AND UPPER(a.ksppinm) LIKE UPPER('\_%') escape '\'

ORDER BY a.ksppinm;