执行select * from v$controlfile;为什么结果是未选定行？

执行select * from v$controlfile;为什么结果是未选定行？

而执行show parameter control_files;
能正确显示控制参数的信息

请问这是问什么？
 

SQL codeselect * from v$controlfile;

show parameter control_files;

STATUS  NAME
------- --------------------------------------------------------------------------------
        D:\ORACLE\ORADATA\FZLGFM\CONTROL01.CTL
        D:\ORACLE\ORADATA\FZLGFM\CONTROL02.CTL
        D:\ORACLE\ORADATA\FZLGFM\CONTROL03.CTL

NAME                                TYPE        VALUE
------------------------------------ ----------- ------------------------------
control_files                        string      d:\oracle\oradata\FZLGFM\CONTROL01.CTL, d:\oracle\oradata\FZLGFM\CONTROL02.CTL, d:\oracle\oradata\FZLGFM\CONTROL03.CTL
 

show parameter显示的内容来自v$parameter
而v$controlfile和v$parameter的基表是不一样的
SQL codeSQL> select * from v$fixed_view_definition where view_name='V$CONTROLFILE';

VIEW_NAME
------------------------------
VIEW_DEFINITION
--------------------------------------------------------------------------------

V$CONTROLFILE
select  STATUS , NAME, IS_RECOVERY_DEST_FILE, BLOCK_SIZE, FILE_SIZE_BLKS  from G

V$CONTROLFILE where inst_id = USERENV('Instance')

SQL> select * from v$fixed_view_definition where view_name='GV$CONTROLFILE';
VIEW_NAME
------------------------------
VIEW_DEFINITION
--------------------------------------------------------------------------------

GV$CONTROLFILE
select inst_id,decode(bitand(cfflg,1),0,'',1,'INVALID'),cfnam, decode(bitand(cff

l2,1),0,'NO','YES'), cfbsz, cffsz  from /*x$kcccf*/
SQL> select * from v$fixed_view_definition where view_name='V$PARAMETER';

VIEW_NAME
------------------------------
VIEW_DEFINITION
--------------------------------------------------------------------------------

V$PARAMETER
select  NUM , NAME , TYPE , VALUE , DISPLAY_VALUE, ISDEFAULT , ISSES_MODIFIABLE
, ISSYS_MODIFIABLE , ISINSTANCE_MODIFIABLE, ISMODIFIED , ISADJUSTED , ISDEPRECAT

ED, DESCRIPTION, UPDATE_COMMENT, HASH  from GV$PARAMETER where inst_id = USERENV

('Instance')

SQL> select * from v$fixed_view_definition where view_name='GV$PARAMETER';

VIEW_NAME
------------------------------
VIEW_DEFINITION
--------------------------------------------------------------------------------

GV$PARAMETER
select x.inst_id,x.indx+1,ksppinm,ksppity,ksppstvl, ksppstdvl, ksppstdf,  decode

(bitand(ksppiflg/256,1),1,'TRUE','FALSE'),  decode(bitand(ksppiflg/65536,3),1,'I

MMEDIATE',2,'DEFERRED',                                  3,'IMMEDIATE','FALSE'),

  decode(bitand(ksppiflg,4),4,'FALSE',                                     decod

e(bitand(ksppiflg/65536,3), 0, 'FALSE', 'TRUE')),     decode(bitand(ksppstvf,7),

1,'MODIFIED',4,'SYSTEM_MOD','FALSE'),  decode(bitand(ksppstvf,2),2,'TRUE','FALSE

'),  decode(bitand(ksppilrmflg/64, 1), 1, 'TRUE', 'FALSE'),  ksppdesc, ksppstcmn

t, ksppihash  from /*x$ksppi x, x$ksppcv y*/ where (x.indx = y.indx) and  ((translat

e(ksppinm,'_','#') not like '##%') and    ((translate(ksppinm,'_','#') not like

'#%')      or (ksppstdf = 'FALSE') or      (bitand(ksppstvf,5) > 0)))