官方解釋:
V$FIXED_TABLE
displays all dynamic performance tables, views, and derived tables in the database. Some V$
tables (for example, V$ROLLNAME
) refer to real
tables and are therefore not listed.
Column | Datatype | Description |
---|---|---|
NAME |
VARCHAR2(30) |
Name of the object |
OBJECT_ID |
NUMBER |
Identifier of the fixed object |
TYPE |
VARCHAR2(5) |
Object type (TABLE | VIEW ) |
TABLE_NUM |
NUMBER |
Number that identifies the dynamic performance table if it is of type TABLE |
V$FIXED_VIEW_DEFINITION
contains the definitions of all the fixed views (views beginning with V$
). Use this table with caution. Oracle tries to keep the behavior of fixed views the same
from release to release, but the definitions of the fixed views can change without notice. Use these definitions to optimize your queries by using indexed columns of the dynamic performance tables.
Column | Datatype | Description |
---|---|---|
VIEW_NAME |
VARCHAR2(30) |
Name of the fixed view |
VIEW_DEFINITION |
VARCHAR2(4000) |
Definition of the fixed view |
NAME,
TYPE,
VALUE,
DISPLAY_VALUE,
ISDEFAULT,
ISSES_MODIFIABLE,
ISSYS_MODIFIABLE,
ISINSTANCE_MODIFIABLE,
ISMODIFIED,
ISADJUSTED,
ISDEPRECATED,
ISBASIC,
DESCRIPTION,
UPDATE_COMMENT,
HASH
FROM GV$PARAMETER
WHERE INST_ID = USERENV('Instance')
X.INDX + 1,
KSPPINM,
KSPPITY,
KSPPSTVL,
KSPPSTDVL,
KSPPSTDF,
DECODE(BITAND(KSPPIFLG / 256, 1), 1, 'TRUE', 'FALSE'),
DECODE(BITAND(KSPPIFLG / 65536, 3),
1,
'IMMEDIATE',
2,
'DEFERRED',
3,
'IMMEDIATE',
'FALSE'),
DECODE(BITAND(KSPPIFLG, 4),
4,
'FALSE',
DECODE(BITAND(KSPPIFLG / 65536, 3), 0, 'FALSE', 'TRUE')),
DECODE(BITAND(KSPPSTVF, 7), 1, 'MODIFIED', 4, 'SYSTEM_MOD', 'FALSE'),
DECODE(BITAND(KSPPSTVF, 2), 2, 'TRUE', 'FALSE'),
DECODE(BITAND(KSPPILRMFLG / 64, 1), 1, 'TRUE', 'FALSE'),
DECODE(BITAND(KSPPILRMFLG / 268435456, 1), 1, 'TRUE', 'FALSE'),
KSPPDESC,
KSPPSTCMNT,
KSPPIHASH
FROM X$KSPPI X, X$KSPPCV Y
WHERE (X.INDX = Y.INDX)
AND BITAND(KSPPIFLG, 268435456) = 0
AND ((TRANSLATE(KSPPINM, '_', '#') NOT LIKE '##%') AND
((TRANSLATE(KSPPINM, '_', '#') NOT LIKE '#%') OR
(KSPPSTDF = 'FALSE') OR (BITAND(KSPPSTVF, 5) > 0)))
這段時間多以動態性能視圖爲討論的焦點,關於動態性能視圖有以下總結:
在實例啓動時,會先創建X$表,然後基於X$表創建GV_$ 和 V_$ 視圖,在基於GV_$ 和V_$視圖創建GV$和V$同義詞。 我們一般查詢的都是同義詞。 關於這些視圖的定義,可以通過V$FIXED_VIEW_DEFINITION 視圖 來查看。 在數據庫運行期間,動態性能視圖保存在內存中,時刻監控着數據庫的狀態,我們在需要的時候可以查看這些視圖。 當實例關閉時,數據庫又會從內存中自動刪除這些動態性能視圖。