sys@META> SELECT a.ksppinm "Parameter", b.ksppstvl "Session Value",
  2         c.ksppstvl "Instance Value"
  3    FROM x$ksppi a, x$ksppcv b, x$ksppsv c
  4   WHERE a.indx = b.indx AND a.indx = c.indx
  5         AND a.ksppinm LIKE '%kgl_large_heap%';

Parameter
--------------------------------------------------------------------------------

Session Value
--------------------------------------------------------------------------------
--------------------
Instance Value
--------------------------------------------------------------------------------
--------------------
_kgl_large_heap_warning_threshold
52428800
52428800

sys@META>

sys@META>alter system set 
   2     _kg_large_heap_warning_threshold=52428800
   3     scope=spfile;