连接到:
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> select * from test;
TESTCOL
--------------------
de
de
SQL> select dbms_rowid.rowid_relative_fno(rowid) file#,dbms_rowid.rowid_block_nu
mber(rowid) blk# from test;
FILE# BLK#
---------- ----------
1 56802
1 56802
SQL> update test set testcol='z';
已更新2行。
SQL> commit
2 ;
提交完成。
SQL> alter system dump datafile 1 block 56802;
系统已更改。
SQL> update test set testcol='zz';
已更新2行。
SQL> commit
2 ;
提交完成。
SQL> alter system dump datafile 1 block 56802;
系统已更改。
SQL> update test set testcol='zzzz';
已更新2行。
SQL> commit
2 ;
提交完成。
SQL> alter system dump datafile 1 block 56802;
系统已更改。
SQL> update test set testcol='zzzz';
已更新2行。
SQL> alter system dump datafile 1 block 56802;
系统已更改。
SQL>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~dump出来的
*** 2008-11-07 11:04:06.921
*** SERVICE NAME:(SYS$USERS) 2008-11-07 11:04:06.906
*** SESSION ID:(154.29) 2008-11-07 11:04:06.906
Start dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
buffer tsn: 0 rdba: 0x0040dde2 (1/56802)
scn: 0x0000.0042ef7d seq: 0x01 flg: 0x02 tail: 0xef7d0601
frmt: 0x02 chkval: 0x0000 type: 0x06=trans data
Block header dump: 0x0040dde2
Object id on Block? Y
seg/obj: 0xd1fb csc: 0x00.428554 itc: 2 flg: O typ: 1 - DATA
fsl: 0 fnx: 0x0 ver: 0x01
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0006.023.000002c3 0x008002ff.01b6.20 C--- 0 scn 0x0000.00428550
0x02 0x0001.02f.000007c2 0x008011b6.02db.12 --U- 2 fsc 0x0000.0042ef7d~~~~~~~~~~~~~~~~~~~已经commit 第一次更新Z时候 旧值得UBA里值de;
data_block_dump,data header at 0x61c025c
===============
tsiz: 0x1fa0
hsiz: 0x1a
pbl: 0x061c025c
bdba: 0x0040dde2
76543210
flag=--------
ntab=1
nrow=4
frre=0
fsbo=0x1a
fseo=0x1e8a
avsp=0x1f74
tosp=0x1f74
0xe:pti[0] nrow=4 offs=0
0x12:pri[0] sfll=1
0x14:pri[1] sfll=-1
0x16:pri[2] offs=0x1e8f
0x18:pri[3] offs=0x1e8a
block_row_dump:
tab 0, row 2, @0x1e8f
tl: 5 fb: --H-FL-- lb: 0x2 cc: 1
col 0: [ 1] 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~第一次更新Z
tab 0, row 3, @0x1e8a
tl: 5 fb: --H-FL-- lb: 0x2 cc: 1
col 0: [ 1] 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~第一次更新Z
end_of_block_dump
End dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
*** 2008-11-07 11:04:21.562
Start dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
buffer tsn: 0 rdba: 0x0040dde2 (1/56802)
scn: 0x0000.0042ef88 seq: 0x01 flg: 0x02 tail: 0xef880601
frmt: 0x02 chkval: 0x0000 type: 0x06=trans data
Block header dump: 0x0040dde2
Object id on Block? Y
seg/obj: 0xd1fb csc: 0x00.42ef85 itc: 2 flg: O typ: 1 - DATA
fsl: 0 fnx: 0x0 ver: 0x01
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0007.027.00000263 0x008008ef.02cd.19 --U- 2 fsc 0x0000.0042ef88~~~第2次更新~zz时候 这个位置的 ITL被换出去了 放入最新更新已提交 uba里值Z
0x02 0x0001.02f.000007c2 0x008011b6.02db.12 C--- 0 scn 0x0000.0042ef7d~~~~~~~~~~~~~~~~~~~~~~~~~~~~原来更新Z时候的 已经变为C uba里值de
data_block_dump,data header at 0x61c025c
===============
tsiz: 0x1fa0
hsiz: 0x1a
pbl: 0x061c025c
bdba: 0x0040dde2
76543210
flag=--------
ntab=1
nrow=4
frre=0
fsbo=0x1a
fseo=0x1e7e
avsp=0x1f74
tosp=0x1f74
0xe:pti[0] nrow=4 offs=0
0x12:pri[0] sfll=1
0x14:pri[1] sfll=-1
0x16:pri[2] offs=0x1e84
0x18:pri[3] offs=0x1e7e
block_row_dump:
tab 0, row 2, @0x1e84
tl: 6 fb: --H-FL-- lb: 0x1 cc: 1
col 0: [ 2] 7a 7a
tab 0, row 3, @0x1e7e
tl: 6 fb: --H-FL-- lb: 0x1 cc: 1
col 0: [ 2] 7a 7a
end_of_block_dump
End dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
Start dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
buffer tsn: 0 rdba: 0x0040dde2 (1/56802)
scn: 0x0000.0042ef8d seq: 0x01 flg: 0x02 tail: 0xef8d0601
frmt: 0x02 chkval: 0x0000 type: 0x06=trans data
Block header dump: 0x0040dde2
Object id on Block? Y
seg/obj: 0xd1fb csc: 0x00.42ef8b itc: 2 flg: O typ: 1 - DATA
fsl: 0 fnx: 0x0 ver: 0x01
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0007.027.00000263 0x008008ef.02cd.19 C--- 0 scn 0x0000.0042ef88~~~~~~~~~~~~~~~~~~~~~更新ZZ时候的 uba里值Z
0x02 0x0003.016.00000bd8 0x0080075b.07fa.28 --U- 2 fsc 0x0000.0042ef8d~~~~~~~~第一次更新Z的已经被换出去变为第3次更新ZZZZ~ UBA里值zz~~~并且已经commit
data_block_dump,data header at 0x61c025c
===============
tsiz: 0x1fa0
hsiz: 0x1a
pbl: 0x061c025c
bdba: 0x0040dde2
76543210
flag=--------
ntab=1
nrow=4
frre=0
fsbo=0x1a
fseo=0x1e6e
avsp=0x1f74
tosp=0x1f74
0xe:pti[0] nrow=4 offs=0
0x12:pri[0] sfll=1
0x14:pri[1] sfll=-1
0x16:pri[2] offs=0x1e76
0x18:pri[3] offs=0x1e6e
block_row_dump:
tab 0, row 2, @0x1e76
tl: 8 fb: --H-FL-- lb: 0x2 cc: 1
col 0: [ 4] 7a 7a 7a 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~zzzzz
tab 0, row 3, @0x1e6e
tl: 8 fb: --H-FL-- lb: 0x2 cc: 1
col 0: [ 4] 7a 7a 7a 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~zzzzz
end_of_block_dump
End dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
Start dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
buffer tsn: 0 rdba: 0x0040dde2 (1/56802)
scn: 0x0000.0042ef90 seq: 0x02 flg: 0x00 tail: 0xef900602
frmt: 0x02 chkval: 0x0000 type: 0x06=trans data
Block header dump: 0x0040dde2
Object id on Block? Y
seg/obj: 0xd1fb csc: 0x00.42ef90 itc: 2 flg: O typ: 1 - DATA
fsl: 0 fnx: 0x0 ver: 0x01
Itl Xid Uba Flag Lck Scn/Fsc
0x01 0x0005.02b.000003c8 0x00800543.0213.20 ---- 2 fsc 0x0000.00000000~~~~~~~~~~~~~~~~~~~~~~第4次更新还为ZZZZ但未提交,UBA里值第一次ZZZZ的
0x02 0x0003.016.00000bd8 0x0080075b.07fa.28 C--- 0 scn 0x0000.0042ef8d~~~~~~~~~~~~~~~~~~~~~~第一次ZZZZ的变为了C,UBA值ZZ
data_block_dump,data header at 0x61c025c
===============
tsiz: 0x1fa0
hsiz: 0x1a
pbl: 0x061c025c
bdba: 0x0040dde2
76543210
flag=--------
ntab=1
nrow=4
frre=0
fsbo=0x1a
fseo=0x1e6e
avsp=0x1f74
tosp=0x1f74
0xe:pti[0] nrow=4 offs=0
0x12:pri[0] sfll=1
0x14:pri[1] sfll=-1
0x16:pri[2] offs=0x1e76
0x18:pri[3] offs=0x1e6e
block_row_dump:
tab 0, row 2, @0x1e76
tl: 8 fb: --H-FL-- lb: 0x1 cc: 1
col 0: [ 4] 7a 7a 7a 7a
tab 0, row 3, @0x1e6e
tl: 8 fb: --H-FL-- lb: 0x1 cc: 1
col 0: [ 4] 7a 7a 7a 7a
end_of_block_dump
End dump data blocks tsn: 0 file#: 1 minblk 56802 maxblk 56802
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~问题来了若一个长时间查询~在还未更新Z时候开始~~当用到更新的这个块的时候,块中ITL 已经无以回滚段信息了 如何构建CR块
问题解决在于 在 undo中也存在 对ITL改变的记录~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~先根据最新的 UBA 0x00800543.0213.20 去找 未COMMIT的
SQL> variable file# number
SQL> variable blk# number
SQL> execute :file#:=dbms_utility.data_block_address_file(to_number('800543','xx
xxxx'));
PL/SQL 过程已成功完成。
SQL> execute :blk#:=dbms_utility.data_block_address_block(to_number('800543','xx
xxxx'));
PL/SQL 过程已成功完成。
SQL> print file#;
FILE#
----------
2
SQL> print blk#;
BLK#
----------
1347
SQL>
SQL> alter system dump datafile 2 block 1347;
系统已更改。
*-----------------------------
* Rec #0x1f slt: 0x2b objn: 53755(0x0000d1fb) objd: 53755 tblspc: 0(0x00000000)
* Layer: 11 (Row) opc: 1 rci 0x00
Undo type: Regular undo Begin trans Last buffer split: No
Temp Object: No
Tablespace Undo: No
rdba: 0x00000000
*-----------------------------
uba: 0x00800543.0213.1d ctl max scn: 0x0000.0042e921 prv tx scn: 0x0000.0042e95b
txn start scn: scn: 0x0000.0042ef90 logon user: 0
prev brb: 8389945 prev bcl: 0
KDO undo record:
KTB Redo
op: 0x04 ver: 0x01
op: L itl: xid: 0x0007.027.00000263 uba: 0x008008ef.02cd.19~~~~~~~~~~~~~~~~~~~~~~~~~~这条记录着 更改ZZ时候的UBA~uba里值Z~还包括ZZ ITL槽中信息
flg: C--- lkc: 0 scn: 0x0000.0042ef88
KDO Op code: URP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x0040dde2 hdba: 0x0040dde1
itli: 1 ispac: 0 maxfr: 4863
tabn: 0 slot: 2(0x2) flag: 0x2c lock: 0 ckix: 6
ncol: 1 nnew: 1 size: 0
col 0: [ 4] 7a 7a 7a 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~保存上一条 更新的ZZZZ
*-----------------------------
* Rec #0x20 slt: 0x2b objn: 53755(0x0000d1fb) objd: 53755 tblspc: 0(0x00000000)
* Layer: 11 (Row) opc: 1 rci 0x1f
Undo type: Regular undo Last buffer split: No
Temp Object: No
Tablespace Undo: No
rdba: 0x00000000
*-----------------------------
KDO undo record:
KTB Redo
op: 0x02 ver: 0x01
op: C uba: 0x00800543.0213.1f
KDO Op code: URP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x0040dde2 hdba: 0x0040dde1
itli: 1 ispac: 0 maxfr: 4863
tabn: 0 slot: 3(0x3) flag: 0x2c lock: 0 ckix: 6
ncol: 1 nnew: 1 size: 0
col 0: [ 4] 7a 7a 7a 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~保存上一条 更新的ZZZZ
End dump data blocks tsn: 1 file#: 2 minblk 1347 maxblk 1347
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~等于替换这个块ITL槽信息的 UBA中记录上一个ITL 记录的信息
~~~~~~~~~~~~~~~~来看看
0x02 0x0003.016.00000bd8 0x0080075b.07fa.28 C--- 0 scn 0x0000.0042ef8d~~~~~~~~~~~~~~~~~~~~~~第一次ZZZZ的变为了C 这个没被换出去的ITL ,中uba 保存什么
SQL> execute :blk#:=dbms_utility.data_block_address_block(to_number('80075b','xx
xxxx'));
PL/SQL 过程已成功完成。
SQL> execute :file#:=dbms_utility.data_block_address_file(to_number('80075b','xx
xxxx'));
PL/SQL 过程已成功完成。
SQL> print file#
FILE#
----------
2
SQL> print blk#
BLK#
----------
1883
SQL> alter system dump datafile 2 block 1883;
系统已更改。
SQL>
* Rec #0x27 slt: 0x16 objn: 53755(0x0000d1fb) objd: 53755 tblspc: 0(0x00000000)
* Layer: 11 (Row) opc: 1 rci 0x00
Undo type: Regular undo Begin trans Last buffer split: No
Temp Object: No
Tablespace Undo: No
rdba: 0x00000000
*-----------------------------
uba: 0x0080075b.07fa.24 ctl max scn: 0x0000.0042e920 prv tx scn: 0x0000.0042e959
txn start scn: scn: 0x0000.0042ef8b logon user: 0
prev brb: 8390488 prev bcl: 0
KDO undo record:
KTB Redo
op: 0x04 ver: 0x01
op: L itl: xid: 0x0001.02f.000007c2 uba: 0x008011b6.02db.12~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~保存第一个更新时候ITL ,Z的 uba
flg: C--- lkc: 0 scn: 0x0000.0042ef7d
KDO Op code: URP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x0040dde2 hdba: 0x0040dde1
itli: 2 ispac: 0 maxfr: 4863
tabn: 0 slot: 2(0x2) flag: 0x2c lock: 0 ckix: 6
ncol: 1 nnew: 1 size: -2
col 0: [ 2] 7a 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~保存ZZ
*-----------------------------
* Rec #0x28 slt: 0x16 objn: 53755(0x0000d1fb) objd: 53755 tblspc: 0(0x00000000)
* Layer: 11 (Row) opc: 1 rci 0x27
Undo type: Regular undo Last buffer split: No
Temp Object: No
Tablespace Undo: No
rdba: 0x00000000
*-----------------------------
KDO undo record:
KTB Redo
op: 0x02 ver: 0x01
op: C uba: 0x0080075b.07fa.27
KDO Op code: URP row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x0040dde2 hdba: 0x0040dde1
itli: 2 ispac: 0 maxfr: 4863
tabn: 0 slot: 3(0x3) flag: 0x2c lock: 0 ckix: 6
ncol: 1 nnew: 1 size: -2
col 0: [ 2] 7a 7a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~保存ZZ~~~~的
~~~假如有一个长时间查询是 更新块之前 开始的(未更新Z时候)查到这个块时候~根据 uba找到UNDO BLK 根据里面信息构造CR块~~~一点点 回滚直到滚到查询SCN大于找到块的SCN
先找到
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