CBO參數學習之查詢隱藏參數

set lines 200
set pages 100
col KSPPINM   for a45                     
col KSPPSTVL  for a10                     
col KSPPDESC  for a80
select x.ksppinm, y.ksppstvl, x.ksppdesc
from x$ksppi x , x$ksppcv y
     where x.indx = y.indx
     and y.inst_id = userenv('Instance')
     and x.inst_id = userenv('Instance')
     and x.ksppinm like '\_%' escape '\'
/

查看該參數可取的值：

select value from  v$parameter_valid_values where name='optimizer_mode';