View Hidden Database Parameters

View All Hidden Parameters:

select 
    ksppinm,ksppstvl 
from 
    x$ksppi a, 
    x$ksppsv b 
where 
    a.indx=b.indx and 
    substr(ksppinm,1,1) = '_';

View a Specific Parameter:

select 
  ksppinm,
  ksppstvl 
from 
  x$ksppi a, 
  x$ksppsv b 
where 
  a.indx=b.indx and 
  ksppinm='_mv_refresh_shrink_log';