關於v$datafile和v$tempfile中的file#，

關於v$datafile和v$tempfile中的file#，

v$datafile視圖中儲存的是有關資料檔案的資訊，v$tempfile視圖中儲存的是有關臨時檔案的資訊。在兩個視圖中都有file#欄位，先來看一下官方文檔的定義：

V$DATAFILE

This view contains datafile information from the control file.

See Also:

"V$DATAFILE_HEADER", which displays information from datafile headers

Column	Datatype	Description
FILE#	NUMBER	File identification number
CREATION_CHANGE#	NUMBER	Change number at which the datafile was created
CREATION_TIME	DATE	Timestamp of the datafile creation
TS#	NUMBER	Tablespace number
RFILE#	NUMBER	Tablespace relative datafile number
STATUS	VARCHAR2(7)	Type of file (system or user) and its status. Values: OFFLINE, ONLINE, SYSTEM, RECOVER, SYSOFF (an offline file from the SYSTEM tablespace)
ENABLED	VARCHAR2(10)	Describes how accessible the file is from SQL: DISABLED - No SQL access allowed READ ONLY - No SQL updates allowed READ WRITE - Full access allowed UNKNOWN - should not occur unless the control file is corrupted
CHECKPOINT_CHANGE#	NUMBER	SCN at last checkpoint
CHECKPOINT_TIME	DATE	Timestamp of the checkpoint#
UNRECOVERABLE_CHANGE#	NUMBER	Last unrecoverable change number made to this datafile. If the database is in ARCHIVELOG mode, then this column is updated when an unrecoverable operation completes. If the database is not in ARCHIVELOG mode, this column does not get updated.
UNRECOVERABLE_TIME	DATE	Timestamp of the last unrecoverable change. This column is updated only if the database is in ARCHIVELOG mode.
LAST_CHANGE#	NUMBER	Last change number made to this datafile (null if the datafile is being changed)
LAST_TIME	DATE	Timestamp of the last change
OFFLINE_CHANGE#	NUMBER	Offline change number of the last offline range. This column is updated only when the datafile is brought online.
ONLINE_CHANGE#	NUMBER	Online change number of the last offline range
ONLINE_TIME	DATE	Online timestamp of the last offline range
BYTES	NUMBER	Current datafile size (in bytes); 0 if inaccessible
BLOCKS	NUMBER	Current datafile size (in blocks); 0 if inaccessible
CREATE_BYTES	NUMBER	Size when created (in bytes)
BLOCK_SIZE	NUMBER	Block size of the datafile
NAME	VARCHAR2(513)	Name of the datafile
PLUGGED_IN	NUMBER	Describes whether the tablespace is plugged in. The value is 1 if the tablespace is plugged in and has not been made read/write, 0 if not.
BLOCK1_OFFSET	NUMBER	Offset from the beginning of the file to where the Oracle generic information begins. The exact length of the file can be computed as follows:BYTES + BLOCK1_OFFSET.
AUX_NAME	VARCHAR2(513)	Auxiliary name that has been set for this file via CONFIGURE AUXNAME
FIRST_NONLOGGED_SCN	NUMBER	First nonlogged SCN
FIRST_NONLOGGED_TIME	DATE	First nonlogged time

V$TEMPFILE

This view displays tempfile information.

Column	Datatype	Description
FILE#	NUMBER	Absolute file number
CREATION_CHANGE#	NUMBER	Creation System Change Number (SCN)
CREATION_TIME	DATE	Creation time
TS#	NUMBER	Tablespace number
RFILE#	NUMBER	Relative file number in the tablespace
STATUS	VARCHAR2(7)	Status of the file (OFFLINE|ONLINE)
ENABLED	VARCHAR2(10)	Enabled for read and/or write
BYTES	NUMBER	Size of the file in bytes (from the file header)
BLOCKS	NUMBER	Size of the file in blocks (from the file header)
CREATE_BYTES	NUMBER	Creation size of the file (in bytes)
BLOCK_SIZE	NUMBER	Block size for the file
NAME	VARCHAR2(513)	Name of the file

從上面的文檔可以看出，在v$tempfile和v$datafile中file#均代表絕對檔案好，而rfile#代表相對檔案號，下面來驗證一下：

SQL> l  1* select file#,name from v$tempfileSQL> /     FILE# NAME---------- ------------------------------------------------------------ 1 /home/app/oraten/oradata/oraten/temp01.dbf

SQL> select file#,name from v$datafile;     FILE# NAME---------- ------------------------------------------------------------ 1 /home/app/oraten/oradata/oraten/system01.dbf 2 /home/app/oraten/oradata/oraten/undotbs01.dbf 3 /home/app/oraten/oradata/oraten/sysaux01.dbf 4 /home/app/oraten/oradata/oraten/users01.dbf 5 /home/app/oraten/oradata/oraten/test01.dbf

在v$datafile和v$tempfile中都存在絕對檔案號為1的檔案，這顯然是不對的。

我們知道在檔案無法訪問時，oracle會報錯並在錯誤資訊中顯示有關檔案的資訊，下面我們來類比臨時檔案的故障

[oraten@yue oraten]$ chmod 000 temp01.dbf [oraten@yue oraten]$ ll總用量 932180-rw-r----- 1 oraten dba   7061504 11月  7 13:59 control01.ctl-rw-r----- 1 oraten dba   7061504 11月  7 13:59 control02.ctl-rw-r----- 1 oraten dba   7061504 11月  7 13:59 control03.ctl-rw-r----- 1 oraten dba  52429312 11月  7 13:44 redo01.log-rw-r----- 1 oraten dba  52429312 11月  7 13:54 redo02.log-rw-r----- 1 oraten dba  52429312 11月  7 13:44 redo03.log-rw-r----- 1 oraten dba 272637952 11月  7 13:49 sysaux01.dbf-rw-r----- 1 oraten dba 461381632 11月  7 13:49 system01.dbf---------- 1 oraten dba  20979712 11月  7 13:39 temp01.dbf-rw-r----- 1 oraten dba  10493952 11月  7 13:44 test01.dbf-rw-r----- 1 oraten dba  26222592 11月  7 13:49 undotbs01.dbf-rw-r----- 1 oraten dba   5251072 11月  7 13:44 users01.dbf

強制啟動資料庫

SQL> startup forceORACLE instance started.Total System Global Area  134217728 bytesFixed Size    2094544 bytesVariable Size   88082992 bytesDatabase Buffers   37748736 bytesRedo Buffers    6291456 bytesDatabase mounted.Database opened.SQL> 

建立暫存資料表，並插入資料

SQL> insert into t1 select * from user_tables;insert into t1 select * from user_tables            *ERROR at line 1:ORA-01157: cannot identify/lock data file 101 - see DBWR trace fileORA-01110: data file 101: '/home/app/oraten/oradata/oraten/temp01.dbf'

呵呵，臨時檔案無法訪問，在這裡顯示的檔案號為101,為什麼那？

我們將參數 db_files修改為200,繼續實驗

SQL> show parameter db_filesNAME     TYPE VALUE------------------------------------ ----------- ------------------------------db_files     integer 100SQL> alter system set db_files=200 scope=spfile;System altered.SQL> startup forceORACLE instance started.Total System Global Area  134217728 bytesFixed Size    2094544 bytesVariable Size   88082992 bytesDatabase Buffers   37748736 bytesRedo Buffers    6291456 bytesDatabase mounted.Database opened.SQL> insert into t1 select * from user_tables;insert into t1 select * from user_tables            *ERROR at line 1:ORA-01157: cannot identify/lock data file 201 - see DBWR trace fileORA-01110: data file 201: '/home/app/oraten/oradata/oraten/temp01.dbf'

原來,v$tempfile中的file#並不是絕對檔案號，臨時檔案的絕對檔案號是file#+db_files參數。

打完手工！！