undo transaction slot被覆盖引起ORA(11)

NAME                                                                  VALUE

---------------------------------------------------------------- ----------

transaction tables consistent reads - undo records applied              310

transaction tables consistent read rollbacks                              1

transaction tables consistent reads - undo records applied              310

表示为了回滚事务表应用了多少undo records，这里为何是310，暂无法证实，我本来认为应该是338的

transaction tables consistent read rollbacks                              1

表示事务表发生了一次回滚的动作

之前我们曾经在session 3里通过alter system dump datafile 8 block min 9 block max 31将所有的undo block dump出来，现在回过头来看一下dump的结果在undo Record 8/17 Rec #0x1里找到了uba: 0x02000010.187e.19，即存放修改前拷贝的undo record：8/16  Rec #0x19，说明这个undo record还在undo chain里

*-----------------------------

* Rec #0x1  slt: 0x13  objn: 270(0x0000010e)  objd: 268  tblspc: 1(0x00000001)

*      Layer:  11 (Row)  opc: 1  rci 0x00

Undo type:  Regular undo    Begin trans    Last buffer split:  No

Temp Object:  No

Tablespace Undo:  No

rdba: 0x00000000Ext idx: 0

flg2: 0

*-----------------------------

uba: 0x02000010.187e.19 ctl max scn: 0x0000.00ae909b prv tx scn: 0x0000.00ae909d

txn start scn: scn: 0x0000.00ae9294 logon user: 0

prev brb: 33554461 prev bcl: 0

KDO undo record:

KTB Redo

op: 0x04  ver: 0x01

compat bit: 4 (post-11) padding: 1

op: L  itl: xid:  0x0002.006.000011d2 uba: 0x0200001f.1877.01

flg: C---    lkc:  0    scn: 0x0000.00ae90b2

KDO Op code: DRP row dependencies Disabled

xtype: XA flags: 0x00000000  bdba: 0x00810de8  hdba: 0x00800192

itli: 2  ispac: 0  maxfr: 4858

tabn: 1 slot: 5(0x5)

##进一步dump 8/16  Rec #0x19的内容，可以看到修改前的内容还在，所以session 2能完成表的遍历

*-----------------------------

* Rec #0x19  slt: 0x1e  objn: 90344(0x000160e8)  objd: 90344  tblspc: 8(0x00000008)

*      Layer:  11 (Row)  opc: 1  rci 0x00

Undo type:  Regular undo    Begin trans    Last buffer split:  No

Temp Object:  No

Tablespace Undo:  No

rdba: 0x00000000Ext idx: 0

flg2: 0

*-----------------------------

uba: 0x02000010.187e.18 ctl max scn: 0x0000.00ae9095 prv tx scn: 0x0000.00ae909b

txn start scn: scn: 0x0000.00ae90b2 logon user: 0

prev brb: 33554460 prev bcl: 0

KDO undo record:

KTB Redo

op: 0x04  ver: 0x01

compat bit: 4 (post-11) padding: 1

op: L  itl: xid:  0x0002.004.0000111f uba: 0x0200001a.177b.09

flg: C---    lkc:  0    scn: 0x0000.00ad9579

KDO Op code: URP row dependencies Disabled

xtype: XA flags: 0x00000000  bdba: 0x010006f3  hdba: 0x010006f2

itli: 2  ispac: 0  maxfr: 4858

tabn: 0 slot: 0(0x0) flag: 0x2c lock: 0 ckix: 0

ncol: 3 nnew: 1 size: 2

col  0: [ 9]  58 53 24 4e 55 4c 4c 4c 4c

/////////////

//session 4:

/////////////

##对proc1.sql脚本的循环次数作略微调整后，分别在循环34次、循环68次、循环102次的情况下，继续对事务槽作覆盖，平均每个事务槽再被覆盖6次，执行调整后的proc1.sql，输出如下：

--proc1.sql调整为循环34次时的输出：

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :1  2,2,4575,8,15,17,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :2  2,22,4574,8,15,18,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :3  2,15,4573,8,15,19,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :4  2,3,4577,8,15,20,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :5  2,7,4576,8,15,21,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :6  2,13,4575,8,15,22,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :7  2,0,4575,8,15,23,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :8  2,19,4571,8,15,24,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :9  2,28,4574,8,15,25,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :10  2,29,4575,8,15,26,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :11  2,4,4571,8,15,27,6271

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :12  2,6,4576,8,24,1,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :13  2,25,4576,8,24,2,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :14  2,16,4577,8,24,3,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :15  2,11,4574,8,24,4,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :16  2,23,4575,8,24,5,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :17  2,33,4574,8,24,6,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :18  2,1,4573,8,24,7,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :19  2,26,4575,8,24,8,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :20  2,24,4574,8,24,9,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :21  2,17,4578,8,24,10,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :22  2,8,4577,8,24,11,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :23  2,20,4575,8,24,12,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :24  2,21,4575,8,24,13,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :25  2,32,4576,8,24,14,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :26  2,12,4572,8,24,15,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :27  2,27,4577,8,24,16,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :28  2,5,4574,8,24,17,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :29  2,14,4575,8,24,18,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :30  2,30,4573,8,24,19,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :31  2,9,4576,8,24,20,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :32  2,10,4577,8,24,21,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :33  2,18,4574,8,24,22,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :34  2,31,4574,8,24,23,6272 

--proc1.sql调整为循环68次时的输出：

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :1  2,21,4576,8,26,1,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :2  2,32,4577,8,26,2,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :3  2,12,4573,8,26,3,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :4  2,27,4578,8,26,4,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :5  2,5,4575,8,26,5,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :6  2,14,4576,8,26,6,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :7  2,30,4574,8,26,7,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :8  2,9,4577,8,26,8,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :9  2,10,4578,8,26,9,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :10  2,18,4575,8,26,10,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :11  2,31,4575,8,26,11,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :12  2,2,4577,8,26,12,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :13  2,22,4576,8,26,13,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :14  2,15,4575,8,26,14,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :15  2,3,4579,8,26,15,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :16  2,7,4578,8,26,16,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :17  2,13,4577,8,26,17,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :18  2,0,4577,8,26,18,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :19  2,19,4573,8,26,19,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :20  2,28,4576,8,26,20,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :21  2,29,4577,8,26,21,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :22  2,4,4573,8,26,22,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :23  2,6,4578,8,26,23,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :24  2,25,4578,8,26,24,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :25  2,16,4579,8,26,25,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :26  2,11,4576,8,26,26,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :27  2,23,4577,8,26,27,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :28  2,33,4576,8,26,28,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :29  2,1,4575,8,26,29,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :30  2,26,4577,8,26,30,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :31  2,24,4576,8,26,31,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :32  2,17,4580,8,26,32,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :33  2,8,4579,8,26,33,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :34  2,20,4577,8,26,34,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :35  2,21,4577,8,27,1,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :36  2,32,4578,8,27,2,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :37  2,12,4574,8,27,3,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :38  2,27,4579,8,27,4,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :39  2,5,4576,8,27,5,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :40  2,14,4577,8,27,6,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :41  2,30,4575,8,27,7,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :42  2,9,4578,8,27,8,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :43  2,10,4579,8,27,9,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :44  2,18,4576,8,27,10,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :45  2,31,4576,8,27,11,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :46  2,2,4578,8,27,12,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :47  2,22,4577,8,27,13,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :48  2,15,4576,8,27,14,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :49  2,3,4580,8,27,15,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :50  2,7,4579,8,27,16,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :51  2,13,4578,8,27,17,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :52  2,0,4578,8,27,18,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :53  2,19,4574,8,27,19,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :54  2,28,4577,8,27,20,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :55  2,29,4578,8,27,21,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :56  2,4,4574,8,27,22,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :57  2,6,4579,8,27,23,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :58  2,25,4579,8,27,24,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :59  2,16,4580,8,27,25,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :60  2,11,4577,8,27,26,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :61  2,23,4578,8,27,27,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :62  2,33,4577,8,27,28,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :63  2,1,4576,8,27,29,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :64  2,26,4578,8,27,30,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :65  2,24,4577,8,27,31,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :66  2,17,4581,8,27,32,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :67  2,8,4580,8,27,33,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :68  2,20,4578,8,27,34,6272

--proc1.sql调整为循环102次时的输出：

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :1  2,21,4578,8,28,1,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :2  2,32,4579,8,28,2,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :3  2,12,4575,8,28,3,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :4  2,27,4580,8,28,4,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :5  2,5,4577,8,28,5,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :6  2,14,4578,8,28,6,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :7  2,30,4576,8,28,7,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :8  2,9,4579,8,28,8,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :9  2,10,4580,8,28,9,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :10  2,18,4577,8,28,10,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :11  2,31,4577,8,28,11,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :12  2,2,4579,8,28,12,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :13  2,22,4578,8,28,13,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :14  2,15,4577,8,28,14,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :15  2,3,4581,8,28,15,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :16  2,7,4580,8,28,16,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :17  2,13,4579,8,28,17,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :18  2,0,4579,8,28,18,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :19  2,19,4575,8,28,19,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :20  2,28,4578,8,28,20,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :21  2,29,4579,8,28,21,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :22  2,4,4575,8,28,22,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :23  2,6,4580,8,28,23,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :24  2,25,4580,8,28,24,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :25  2,16,4581,8,28,25,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :26  2,11,4578,8,28,26,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :27  2,23,4579,8,28,27,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :28  2,33,4578,8,28,28,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :29  2,1,4577,8,28,29,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :30  2,26,4579,8,28,30,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :31  2,24,4578,8,28,31,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :32  2,17,4582,8,28,32,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :33  2,8,4581,8,28,33,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :34  2,20,4579,8,28,34,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :35  2,21,4579,8,29,1,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :36  2,32,4580,8,29,2,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :37  2,12,4576,8,29,3,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :38  2,27,4581,8,29,4,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :39  2,5,4578,8,29,5,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :40  2,14,4579,8,29,6,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :41  2,30,4577,8,29,7,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :42  2,9,4580,8,29,8,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :43  2,10,4581,8,29,9,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :44  2,18,4578,8,29,10,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :45  2,31,4578,8,29,11,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :46  2,2,4580,8,29,12,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :47  2,22,4579,8,29,13,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :48  2,15,4578,8,29,14,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :49  2,3,4582,8,29,15,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :50  2,7,4581,8,29,16,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :51  2,13,4580,8,29,17,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :52  2,0,4580,8,29,18,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :53  2,19,4576,8,29,19,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :54  2,28,4579,8,29,20,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :55  2,29,4580,8,29,21,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :56  2,4,4576,8,29,22,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :57  2,6,4581,8,29,23,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :58  2,25,4581,8,29,24,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :59  2,16,4582,8,29,25,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :60  2,11,4579,8,29,26,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :61  2,23,4580,8,29,27,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :62  2,33,4579,8,29,28,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :63  2,1,4578,8,29,29,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :64  2,26,4580,8,29,30,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :65  2,24,4579,8,29,31,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :66  2,17,4583,8,29,32,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :67  2,8,4582,8,29,33,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :68  2,20,4580,8,29,34,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :69  2,21,4580,8,30,1,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :70  2,32,4581,8,30,2,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :71  2,12,4577,8,30,3,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :72  2,27,4582,8,30,4,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :73  2,5,4579,8,30,5,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :74  2,14,4580,8,30,6,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :75  2,30,4578,8,30,7,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :76  2,9,4581,8,30,8,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :77  2,10,4582,8,30,9,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :78  2,18,4579,8,30,10,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :79  2,31,4579,8,30,11,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :80  2,2,4581,8,30,12,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :81  2,22,4580,8,30,13,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :82  2,15,4579,8,30,14,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :83  2,3,4583,8,30,15,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :84  2,7,4582,8,30,16,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :85  2,13,4581,8,30,17,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :86  2,0,4581,8,30,18,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :87  2,19,4577,8,30,19,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :88  2,28,4580,8,30,20,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :89  2,29,4581,8,30,21,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :90  2,4,4577,8,30,22,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :91  2,6,4582,8,30,23,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :92  2,25,4582,8,30,24,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :93  2,16,4583,8,30,25,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :94  2,11,4580,8,30,26,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :95  2,23,4581,8,30,27,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :96  2,33,4580,8,30,28,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :97  2,1,4579,8,30,29,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :98  2,26,4581,8,30,30,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :99  2,24,4580,8,30,31,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :100  2,17,4584,8,30,32,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :101  2,8,4583,8,30,34,6272

XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBAREC,UBASQN  :102  2,20,4581,8,30,35,6272

/////////////

//session 2:

/////////////

##在session 4对每个事务槽各覆盖6遍的基础上，再次遍历scott.tabnow1表，依然能查到scott.tabnow1修改前的拷贝

select * from scott.tabnow1;

USERNAME                          USER_ID CREATED

------------------------------ ---------- ------------

XS$NULLLL                      2147483638 21-OCT-11

NEWUSER                                84 12-MAR-14

SCOTTTTT                              83 21-OCT-11

OWBSYS_AUDIT                          82 21-OCT-11

OWBSYS                                78 21-OCT-11

APEX                                  77 21-OCT-11

APEX_PUBLIC                            75 21-OCT-11

FLOWS_FILE                            74 21-OCT-11

MGMT_VIEW                              73 21-OCT-11

DDD                                    34 28-MAY-14

在session 4再次尝试覆盖的过程中，通过proc1.sql执行输出的xid，uba信息获知undo record ：8/25 Rec#0x19并没有被使用到.

##dump 所有undo块

alter system dump datafile 8 block min 9 block max 31;