隠しパラメータの確認方法

OracleDatabase 
set lines 140 pages 10000
col parameter   format a40
col value       format a20
col description format a60

select
  a.ksppinm as parameter,
  b.ksppstvl as value,
  a.KSPPDESC as description
from x$ksppi a , x$ksppcv b
where a.indx = b.indx
and a.ksppinm Like '_%' ;

参考

http://system3support.jp/pdf/oracle_knowledge/100_technique/p296.pdf