查看隐含参数

 可以使用如下脚本查看隐含参数
SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ
FROM SYS.x$ksppi x, SYS.x$ksppcv y
WHERE x.inst_id = USERENV ('Instance')
AND y.inst_id = USERENV ('Instance')
AND x.indx = y.indx
AND x.ksppinm LIKE '%&par%'
/

例如我要查看 _shared_pool_reserved_min_alloc隐含参数

SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ
  2  FROM SYS.x$ksppi x, SYS.x$ksppcv y
  3  WHERE x.inst_id = USERENV ('Instance')
  4  AND y.inst_id = USERENV ('Instance')
  5  AND x.indx = y.indx
  6  AND x.ksppinm LIKE '%&par%'
  7  /
Enter value for par: _shared_pool_reserved_min
old   6: AND x.ksppinm LIKE '%&par%'
new   6: AND x.ksppinm LIKE '%_shared_pool_reserved_min%'

NAME                                VALUE      DESCRIB
----------------------------------- ---------- ------------------------------
_shared_pool_reserved_min_alloc     4100       minimum allocation size in bytes for reserved area of shared pool

修改隐含参数

SQL> alter system set "_shared_pool_reserved_min_alloc"=4400 scope=spfile;

System altered.

查看SCN  

SELECT ksppinm, ksppstvl, ksppdesc
  FROM x$ksppi x, x$ksppcv y
 WHERE x.indx = y.indx
   AND ksppinm = '_external_scn_rejection_threshold_hours';