这个工具有如下特点：
- 以只读的方式打开数据文件，在检查过程中不会修改数据文件的内容。
- 可以在线检查数据文件，而不需要关闭数据库。
- 不能检查控制文件和日志文件，只能检查数据文件。
- 这个工具可以检查ASM文件，但数据库必须Open状态，并且需要通过USERID指定用户，比如：dbv file=+DG1/ORCL/datafile/system01.dbf userid=system/sys
- 在许多UNIX平台下，DBV要求数据文件有扩展名，如果没有可以通过建立链接的方法，然后对链接的方法，然后对链接文件进行操作，比如：ls -n /dev/rdsk/mydevice /tmp/mydevice.dbf
- 某些平台，DBV工具不能检查超过2GB的文件，如果碰到DBV-100错误，请先检查文件大小，MOS Bug 710888对这个问题有描述。
- DBV只会检查数据块的正确性，但不会关系数据块是否属于哪个对象。
- 对于祼设备建议指定END参数，避免超出数据文件范围。比如：dbv FILE=/dev/rdsk/r1.dbf END=<last_block_number>。可以在v$datafile视图中用bytes字段除以块大小来获得END值。
| 参数 | 含义 | 缺省值 |
| FILE | 要检查的数据文件名 | 没有缺省值 |
| START | 检查起始数据块号 | 数据文件的第一个数据块 |
| END | 检查的最后一个数据块号 | 数据文件的最后一个数据块 |
| BLOCKSIZE | 数据块大小，这个值要和数据库的DB_BLOCK_SIZE参数值一致 | 缺省值8192 |
| LOGFILE | 检查结果日志文件 | 没有缺省值 |
| FEEDBAK | 显示进度 | 0 |
| PARFILE | 参数文件名 | 没有缺省值 |
| USERID | 用户名、密码 | 没有缺省值 |
| SEGMENT_ID | 段ID，参数格式<tsn.segfile.segblock> | 没有缺省值 |
使用示例：
[oracle@rhel6 ~]$ dbv
file
=
/u01/app/oracle/oradata/test/users01
.dbf
DBVERIFY: Release 11.2.0.1.0 - Production on Mon May 22 16:42:26 2017
Copyright (c) 1982, 2009, Oracle and
/or
its affiliates. All rights reserved.
DBVERIFY - Verification starting : FILE =
/u01/app/oracle/oradata/test/users01
.dbf
DBVERIFY - Verification complete
Total Pages Examined : 155520
Total Pages Processed (Data) : 144530
Total Pages Failing (Data) : 0
Total Pages Processed (Index): 52
Total Pages Failing (Index): 0
Total Pages Processed (Other): 1248
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 9690
Total Pages Marked Corrupt : 0
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 3559792 (0.3559792)
这个工具报告使用的是page作为单位，含义和data block相同。从上面的检查结果Total Pages Marked Corrupt : 0可以看出文件没有坏块。
除了检查数据文件，这个工具还允许检查单独的Segment，这时参数值的格式为<tsn.segfile.segblock>
查看对象的tsn,segfile,segblock属性：
zx@TEST>
select
t.ts#,s.header_file,s.header_block
2
from
v$tablespace t,dba_segments s
3
where
s.segment_name=
'T'
4
and
t.
name
=s.tablespace_name;
TS# HEADER_FILE HEADER_BLOCK
---------- ----------- ------------
4 4 45834
从上面的查询结果可行参数值为4.4.45834。检查Segment：
[oracle@rhel6 ~]$ dbv userid=system
/123456
segment_id=4.4.45834
DBVERIFY: Release 11.2.0.1.0 - Production on Mon May 22 20:58:33 2017
Copyright (c) 1982, 2009, Oracle and
/or
its affiliates. All rights reserved.
DBVERIFY - Verification starting : SEGMENT_ID = 4.4.45834
DBVERIFY - Verification complete
Total Pages Examined : 8
Total Pages Processed (Data) : 5
Total Pages Failing (Data) : 0
Total Pages Processed (Index): 0
Total Pages Failing (Index): 0
Total Pages Processed (Other): 2
Total Pages Processed (Seg) : 1
Total Pages Failing (Seg) : 0
Total Pages Empty : 0
Total Pages Marked Corrupt : 0
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 3518579 (0.3518579)
下面人为创造一个坏块，用dbv来检查。
创建一个测试表
zx@TEST>
create
table
bbed (id number,
name
varchar2(20)) tablespace users;
Table
created.
zx@TEST>
insert
into
bbed
values
(1,
'zhaoxu'
);
1 row created.
zx@TEST>
commit
;
Commit
complete.
当前数据文件没有坏块
[oracle@rhel6 ~]$ dbv
file
=
/u01/app/oracle/oradata/test/users01
.dbf
DBVERIFY: Release 11.2.0.1.0 - Production on Mon May 22 21:03:40 2017
Copyright (c) 1982, 2009, Oracle and
/or
its affiliates. All rights reserved.
DBVERIFY - Verification starting : FILE =
/u01/app/oracle/oradata/test/users01
.dbf
DBVERIFY - Verification complete
Total Pages Examined : 155520
Total Pages Processed (Data) : 66397
Total Pages Failing (Data) : 0
Total Pages Processed (Index): 52
Total Pages Failing (Index): 0
Total Pages Processed (Other): 88898
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 173
Total Pages Marked Corrupt : 0
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 3764775 (0.3764775)
获取表在文件中的存储信息
zx@TEST>
set
serveroutput
on
zx@TEST>
declare
rfno number;
2 rtype number;
3 ono number;
4 blkno number;
5 rowno number;
6 rid varchar2(30);
7
begin
8
select
rowid
into
rid
from
bbed;
9 dbms_rowid.rowid_info(ROWID_IN=>rid,RELATIVE_FNO=>rfno,BLOCK_NUMBER=>blkno,ROW_NUMBER=>rowno,ROWID_TYPE=>rtype,OBJECT_NUMBER=>ono);
10 dbms_output.put_line(rfno||
','
||blkno||
','
||rowno);
11
end
;
12 /
4,45844,0
PL/SQL
procedure
successfully completed.
使用bbed修改块信息
[oracle@rhel6 bbed]$ bbed parfile=bbed.par
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Mon May 22 21:17:18 2017
Copyright (c) 1982, 2009, Oracle and
/or
its affiliates. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED>
set
dba 4,45844
DBA 0x0100b314 (16823060 4,45844)
BBED>
find
/c
zhaoxu
File:
/u01/app/oracle/oradata/test/users01
.dbf (4)
Block: 45844 Offsets: 8182 to 8191 Dba:0x0100b314
------------------------------------------------------------------------
7a68616f 78750106 5873
<32 bytes per line>
BBED> dump
/v
dba 4,45844 offset 8182 count 32
File:
/u01/app/oracle/oradata/test/users01
.dbf (4)
Block: 45844 Offsets: 8182 to 8191 Dba:0x0100b314
-------------------------------------------------------
7a68616f 78750106 5873 l zhaoxu..Xs
<16 bytes per line>
BBED> modify 100 dba 4,45844
Warning: contents of previous BIFILE will be lost. Proceed? (Y
/N
) y
File:
/u01/app/oracle/oradata/test/users01
.dbf (4)
Block: 45844 Offsets: 8182 to 8191 Dba:0x0100b314
------------------------------------------------------------------------
6468616f 78750106 5873
<32 bytes per line>
BBED> dump
/v
dba 4,45844 offset 8182 count 32
File:
/u01/app/oracle/oradata/test/users01
.dbf (4)
Block: 45844 Offsets: 8182 to 8191 Dba:0x0100b314
-------------------------------------------------------
6468616f 78750106 5873 l dhaoxu..Xs
<16 bytes per line>
BBED>
exit
再次使用dbv检查文件
[oracle@rhel6 bbed]$ dbv
file
=
/u01/app/oracle/oradata/test/users01
.dbf
DBVERIFY: Release 11.2.0.1.0 - Production on Mon May 22 21:18:46 2017
Copyright (c) 1982, 2009, Oracle and
/or
its affiliates. All rights reserved.
DBVERIFY - Verification starting : FILE =
/u01/app/oracle/oradata/test/users01
.dbf
Page 45844 is marked corrupt
Corrupt block relative dba: 0x0100b314 (
file
4, block 45844)
Bad check value found during dbv:
Data
in
bad block:
type
: 6
format
: 2 rdba: 0x0100b314
last change scn: 0x0000.00397358
seq
: 0x1 flg: 0x04
spare1: 0x0 spare2: 0x0 spare3: 0x0
consistency value
in
tail
: 0x73580601
check value
in
block header: 0x7c2d
computed block checksum: 0x1e
DBVERIFY - Verification complete
Total Pages Examined : 155520
Total Pages Processed (Data) : 66396
Total Pages Failing (Data) : 0
Total Pages Processed (Index): 52
Total Pages Failing (Index): 0
Total Pages Processed (Other): 88898
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 173
Total Pages Marked Corrupt : 1
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 3764775 (0.3764775)
报告一个坏块，Total Pages Marked Corrupt : 1
再次查询测试表：
sys@TEST>
select
*
from
zx.bbed;
ID
NAME
---------- ------------------------------------------------------------
1 zhaoxu
查询正常，因为在buffer_cache中缓存了块，而修改的是文件中的块。两个块现在不一致，清空buffer cache后再次查询测试表。
zx@TEST>
alter
system flush buffer_cache;
System altered.
zx@TEST>
select
*
from
bbed;
select
*
from
bbed
*
ERROR
at
line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 45844)
ORA-01110: data file 4:
'/u01/app/oracle/oradata/test/users01.dbf'
查询报出错误ORA-01578。
使用dbv检查ASM文件中的数据文件，需要指定userid参数
[oracle@rac1 ~]$ dbv file=+DATA/orcl/datafile/users.259.925306091 userid=sys/123456
DBVERIFY: Release 11.2.0.4.0 - Production
on
Mon May 22 16:48:22 2017
Copyright (c) 1982, 2011, Oracle
and
/
or
its affiliates.
All
rights reserved.
DBVERIFY - Verification starting : FILE = +DATA/orcl/datafile/users.259.925306091
DBVERIFY - Verification complete
Total Pages Examined : 640
Total Pages Processed (Data) : 16
Total Pages Failing (Data) : 0
Total Pages Processed (
Index
): 2
Total Pages Failing (
Index
): 0
Total Pages Processed (Other): 593
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 29
Total Pages Marked Corrupt : 0
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 0 (0.0)