使用DUMP数据块与BBED查看BLOCK对比数据库修改时的SCN
实验思路：
先在数据库中对bys.a表的一行进行更新，查出此行对应的FILE# BLOCK#
然后DUMP此FILE# BLOCK#，查看SCN信息
使用BBED DUMP此FILE# BLOCK#，查看SCN信息
B
----------
55
7
3
19:55:15 BYS@ bys3>update a set b=0 where b=7;
1 row updated.
19:55:38 BYS@ bys3>commit;
Commit complete.
19:55:40 BYS@ bys3>select rowid,b from a; ---COMMIT的时间是19:55:40
ROWID B
------------------ ----------
AAAFOzAAEAAAACSAAA 55
AAAFOzAAEAAAACZAAA 0
AAAFOzAAEAAAACbAAA 3
19:57:15 BYS@ bys3>col object_name for a10
20:01:04 BYS@ bys3>select a.rowid,a.object_id,a.file_id,a.block_id,a.row_id,b.object_name, b from (select rowid,dbms_rowid.rowid_object(rowid) object_id,dbms_rowid.rowid_relative_fno(rowid) file_id,dbms_rowid.rowid_block_number(rowid) block_id,dbms_rowid.rowid_row_number(rowid) row_id,b from bys.a) a,dba_objects b where a.object_id=b.object_id; ---如使用此语句，只需要修改标红出的表名，字段名即可。
ROWID OBJECT_ID FILE_ID BLOCK_ID ROW_ID OBJECT_NAM B
------------------ ---------- ---------- ---------- ---------- ---------- ----------
AAAFOzAAEAAAACbAAA 21427 4 155 0 A 3
AAAFOzAAEAAAACZAAA 21427 4 153 0 A 0
AAAFOzAAEAAAACSAAA 21427 4 146 0 A 55
通过上面的语句可以查询出update a set b=0 where b=7;修改数据块是：file#4,block#153
###################################################################
System altered.
查看TRACE文件位置方法有三个：
select value from v$diag_info where name like 'Default%';
SYS用户执行：oradebug setmypid; oradebug tracefile_name
或者直接在user_dump_dest目录中使用 ls -alt 找最近生成的文件
20:05:32 BYS@ bys3>col name for a10
20:05:40 BYS@ bys3>col value for a50
20:05:49 BYS@ bys3>select * from v$diag_info where name like 'Default%';
INST_ID NAME VALUE
---------- ---------- --------------------------------------------------
1 Default Tr /u01/app/oracle/product/11.2.0/dbhome_1/log/diag/r
ace File dbms/bys3/bys3/trace/bys3_ora_17341.trc
从DUMP信息中查出修改时SCN为：scn: 0x0000.00197b75 ---详见下面的TRACE文件具体信息
转换为SCN为:
20:19:17 BYS@ bys3>select to_number('197b75','xxxxxxxxx') from dual;
TO_NUMBER('197B75','XXXXXXXXX')
-------------------------------
1670005
20:19:38 BYS@ bys3>select scn_to_timestamp(1670005) from dual; --把SCN转换为时间，验证此SCN与UPDATE语句提交时的相符。
SCN_TO_TIMESTAMP(1670005)
---------------------------------------------------------------------------
29-NOV-13 07.55.39.000000000 PM
查看bys3_ora_17341.trc中的详细信息如下：===截取块头部分信息：
Start dump data blocks tsn: 4 file#:4 minblk 153 maxblk 153
Block dump from cache:
Dump of buffer cache at level 4 for tsn=4 rdba=16777369
BH (0x22bfad14) file#: 4 rdba: 0x01000099 (4/153) class: 1 ba: 0x22b9e000
set: 3 pool: 3 bsz: 8192 bsi: 0 sflg: 1 pwc: 0,0
dbwrid: 0 obj: 21427 objn: 21427 tsn: 4 afn: 4 hint: f
hash: [0x22bfba7c,0x2879bdd8] lru: [0x22bfaea4,0x22bfac10]
ckptq: [NULL] fileq: [NULL] objq: [0x22bfaebc,0x25040784] objaq: [0x22bfbba8,0x22bfb9f0]
st: XCURRENT md: NULL fpin: 'kdswh01: kdstgr' tch: 6
flags: block_written_once redo_since_read
LRBA: [0x0.0.0] LSCN: [0x0.0] HSCN: [0xffff.ffffffff] HSUB: [1]
BH (0x22bfb9f8) file#: 4 rdba: 0x01000099 (4/153) class: 1 ba: 0x22bbc000
set: 3 pool: 3 bsz: 8192 bsi: 0 sflg: 1 pwc: 0,0
dbwrid: 0 obj: 21427 objn: 21427 tsn: 4 afn: 4 hint: f
hash: [0x2879bdd8,0x22bfad98] lru: [0x22bfacec,0x217e4bb8]
lru-flags: hot_buffer
ckptq: [NULL] fileq: [NULL] objq: [NULL] objaq: [NULL]
st: CR md: NULL fpin: 'kdswh01: kdstgr' tch: 0
cr: [scn: 0x0.197b72],[xid: 0x0.0.0],[uba: 0x0.0.0],[cls: 0x0.197b72],[sfl: 0x0],[lc: 0x0.14da6c]
flags: only_sequential_access
Block dump from disk:
buffer tsn: 4 rdba: 0x01000099 (4/153)
scn: 0x0000.00197b75 seq: 0x02 flg: 0x06 tail: 0x7b750602
frmt: 0x02 chkval: 0xe52c type: 0x06=trans data
Hex dump of block: st=0, typ_found=1
Dump of memory from 0xB6C41600 to 0xB6C43600
##########################################################3
blocksize=8192
listfile=bbedfile.txt
mode=edit
[oracle@bys3 ~]$ cat bbedfile.txt
1 /u01/oradata/bys3/system01.dbf 524288000
2 /u01/oradata/bys3/sysaux01.dbf 340787200
3 /u01/oradata/bys3/undotbs01.dbf 209715200
4 /u01/oradata/bys3/user01.dbf 52428800
[oracle@bys3 ~]$ bbed parfile=par.bbd
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Fri Nov 29 20:22:10 2013
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED> set file 4 block 153
FILE# 4
BLOCK# 153
BBED> map
File: /u01/oradata/bys3/user01.dbf (4)
Block: 153 Dba:0x01000099
------------------------------------------------------------
KTB Data Block (Table/Cluster)
struct kcbh, 20 bytes @0
struct ktbbh, 72 bytes @20
struct kdbh, 14 bytes @100
struct kdbt[1], 4 bytes @114
sb2 kdbr[660] @118
ub1 freespace[719] @1438
ub1 rowdata[6031] @2157
ub4 tailchk @8188
BBED> print kcbh
struct kcbh, 20 bytes @0
ub1 type_kcbh @0 0x06
ub1 frmt_kcbh @1 0xa2
ub1 spare1_kcbh @2 0x00
ub1 spare2_kcbh @3 0x00
ub4 rdba_kcbh @4 0x01000099
ub4 bas_kcbh @8 0x00197b75 ---从名字就比较好看出是scn wrap和scn base
ub2 wrp_kcbh @12 0x0000
ub1 seq_kcbh @14 0x02
ub1 flg_kcbh @15 0x06 (KCBHFDLC, KCBHFCKV)
ub2 chkval_kcbh @16 0xe52c
ub2 spare3_kcbh @18 0x0000
下面两行对应的就是SCN的scn wrap 高16位-2byte和scn base 低32位-4byte 详见：http://blog.csdn.net/q947817003/article/details/11590983
ub4 bas_kcbh @8 0x00197b75
ub2 wrp_kcbh @12 0x0000
scn计算方法：SCN=(SCN_WRP * 4294967296) + SCN_BAS
所以此数据块上的SCN就是：0x0000.00197b75 --对应十进制SCN：1670005 对应时间：29-NOV-13 07.55.39.000000000 PM
这个SCN的值与在数据库中使用DUMP file#4,block#153数据块信息得出的SCN是一致的。此处的SCN:0x0000.00197b75转换为十进制SCN及转换为时间详见上一步DUMP时的转换，不详细写出了。
先在数据库中对bys.a表的一行进行更新，查出此行对应的FILE# BLOCK#
然后DUMP此FILE# BLOCK#，查看SCN信息
使用BBED DUMP此FILE# BLOCK#，查看SCN信息
1.在数据库中对 bys.a表的一行进行更新，记录此行的ROWID。
19:55:13 BYS@ bys3>select * from a;B
----------
55
7
3
19:55:15 BYS@ bys3>update a set b=0 where b=7;
1 row updated.
19:55:38 BYS@ bys3>commit;
Commit complete.
19:55:40 BYS@ bys3>select rowid,b from a; ---COMMIT的时间是19:55:40
ROWID B
------------------ ----------
AAAFOzAAEAAAACSAAA 55
AAAFOzAAEAAAACZAAA 0
AAAFOzAAEAAAACbAAA 3
19:57:15 BYS@ bys3>col object_name for a10
20:01:04 BYS@ bys3>select a.rowid,a.object_id,a.file_id,a.block_id,a.row_id,b.object_name, b from (select rowid,dbms_rowid.rowid_object(rowid) object_id,dbms_rowid.rowid_relative_fno(rowid) file_id,dbms_rowid.rowid_block_number(rowid) block_id,dbms_rowid.rowid_row_number(rowid) row_id,b from bys.a) a,dba_objects b where a.object_id=b.object_id; ---如使用此语句，只需要修改标红出的表名，字段名即可。
ROWID OBJECT_ID FILE_ID BLOCK_ID ROW_ID OBJECT_NAM B
------------------ ---------- ---------- ---------- ---------- ---------- ----------
AAAFOzAAEAAAACbAAA 21427 4 155 0 A 3
AAAFOzAAEAAAACZAAA 21427 4 153 0 A 0
AAAFOzAAEAAAACSAAA 21427 4 146 0 A 55
通过上面的语句可以查询出update a set b=0 where b=7;修改数据块是：file#4,block#153
###################################################################
2.使用DUMP file#4,block#153数据块来查看此块相关信息---主要是修改时的SCN
20:01:36 BYS@ bys3> alter system dump datafile 4 block 153;System altered.
查看TRACE文件位置方法有三个：
select value from v$diag_info where name like 'Default%';
SYS用户执行：oradebug setmypid; oradebug tracefile_name
或者直接在user_dump_dest目录中使用 ls -alt 找最近生成的文件
20:05:32 BYS@ bys3>col name for a10
20:05:40 BYS@ bys3>col value for a50
20:05:49 BYS@ bys3>select * from v$diag_info where name like 'Default%';
INST_ID NAME VALUE
---------- ---------- --------------------------------------------------
1 Default Tr /u01/app/oracle/product/11.2.0/dbhome_1/log/diag/r
ace File dbms/bys3/bys3/trace/bys3_ora_17341.trc
从DUMP信息中查出修改时SCN为：scn: 0x0000.00197b75 ---详见下面的TRACE文件具体信息
转换为SCN为:
20:19:17 BYS@ bys3>select to_number('197b75','xxxxxxxxx') from dual;
TO_NUMBER('197B75','XXXXXXXXX')
-------------------------------
1670005
20:19:38 BYS@ bys3>select scn_to_timestamp(1670005) from dual; --把SCN转换为时间，验证此SCN与UPDATE语句提交时的相符。
SCN_TO_TIMESTAMP(1670005)
---------------------------------------------------------------------------
29-NOV-13 07.55.39.000000000 PM
查看bys3_ora_17341.trc中的详细信息如下：===截取块头部分信息：
Start dump data blocks tsn: 4 file#:4 minblk 153 maxblk 153
Block dump from cache:
Dump of buffer cache at level 4 for tsn=4 rdba=16777369
BH (0x22bfad14) file#: 4 rdba: 0x01000099 (4/153) class: 1 ba: 0x22b9e000
set: 3 pool: 3 bsz: 8192 bsi: 0 sflg: 1 pwc: 0,0
dbwrid: 0 obj: 21427 objn: 21427 tsn: 4 afn: 4 hint: f
hash: [0x22bfba7c,0x2879bdd8] lru: [0x22bfaea4,0x22bfac10]
ckptq: [NULL] fileq: [NULL] objq: [0x22bfaebc,0x25040784] objaq: [0x22bfbba8,0x22bfb9f0]
st: XCURRENT md: NULL fpin: 'kdswh01: kdstgr' tch: 6
flags: block_written_once redo_since_read
LRBA: [0x0.0.0] LSCN: [0x0.0] HSCN: [0xffff.ffffffff] HSUB: [1]
BH (0x22bfb9f8) file#: 4 rdba: 0x01000099 (4/153) class: 1 ba: 0x22bbc000
set: 3 pool: 3 bsz: 8192 bsi: 0 sflg: 1 pwc: 0,0
dbwrid: 0 obj: 21427 objn: 21427 tsn: 4 afn: 4 hint: f
hash: [0x2879bdd8,0x22bfad98] lru: [0x22bfacec,0x217e4bb8]
lru-flags: hot_buffer
ckptq: [NULL] fileq: [NULL] objq: [NULL] objaq: [NULL]
st: CR md: NULL fpin: 'kdswh01: kdstgr' tch: 0
cr: [scn: 0x0.197b72],[xid: 0x0.0.0],[uba: 0x0.0.0],[cls: 0x0.197b72],[sfl: 0x0],[lc: 0x0.14da6c]
flags: only_sequential_access
Block dump from disk:
buffer tsn: 4 rdba: 0x01000099 (4/153)
scn: 0x0000.00197b75 seq: 0x02 flg: 0x06 tail: 0x7b750602
frmt: 0x02 chkval: 0xe52c type: 0x06=trans data
Hex dump of block: st=0, typ_found=1
Dump of memory from 0xB6C41600 to 0xB6C43600
##########################################################3
3.使用BBED 查看file#4,block#153数据块中的SCN信息
[oracle@bys3 ~]$ cat par.bbdblocksize=8192
listfile=bbedfile.txt
mode=edit
[oracle@bys3 ~]$ cat bbedfile.txt
1 /u01/oradata/bys3/system01.dbf 524288000
2 /u01/oradata/bys3/sysaux01.dbf 340787200
3 /u01/oradata/bys3/undotbs01.dbf 209715200
4 /u01/oradata/bys3/user01.dbf 52428800
[oracle@bys3 ~]$ bbed parfile=par.bbd
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Fri Nov 29 20:22:10 2013
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED> set file 4 block 153
FILE# 4
BLOCK# 153
BBED> map
File: /u01/oradata/bys3/user01.dbf (4)
Block: 153 Dba:0x01000099
------------------------------------------------------------
KTB Data Block (Table/Cluster)
struct kcbh, 20 bytes @0
struct ktbbh, 72 bytes @20
struct kdbh, 14 bytes @100
struct kdbt[1], 4 bytes @114
sb2 kdbr[660] @118
ub1 freespace[719] @1438
ub1 rowdata[6031] @2157
ub4 tailchk @8188
BBED> print kcbh
struct kcbh, 20 bytes @0
ub1 type_kcbh @0 0x06
ub1 frmt_kcbh @1 0xa2
ub1 spare1_kcbh @2 0x00
ub1 spare2_kcbh @3 0x00
ub4 rdba_kcbh @4 0x01000099
ub4 bas_kcbh @8 0x00197b75 ---从名字就比较好看出是scn wrap和scn base
ub2 wrp_kcbh @12 0x0000
ub1 seq_kcbh @14 0x02
ub1 flg_kcbh @15 0x06 (KCBHFDLC, KCBHFCKV)
ub2 chkval_kcbh @16 0xe52c
ub2 spare3_kcbh @18 0x0000
下面两行对应的就是SCN的scn wrap 高16位-2byte和scn base 低32位-4byte 详见：http://blog.csdn.net/q947817003/article/details/11590983
ub4 bas_kcbh @8 0x00197b75
ub2 wrp_kcbh @12 0x0000
scn计算方法：SCN=(SCN_WRP * 4294967296) + SCN_BAS
所以此数据块上的SCN就是：0x0000.00197b75 --对应十进制SCN：1670005 对应时间：29-NOV-13 07.55.39.000000000 PM
这个SCN的值与在数据库中使用DUMP file#4,block#153数据块信息得出的SCN是一致的。此处的SCN:0x0000.00197b75转换为十进制SCN及转换为时间详见上一步DUMP时的转换，不详细写出了。