下面几个步骤是查看一个完整的transaction 必要的几个步骤

1/ find xid,segment header
select xidusn,xidslot,xidsqn,ubablk,ubafil,ubarec from v$transaction;
2/alter system dump undo header '_SYSSMU9$';
3/find undo block by rdba which dumped by step 2
4 /alter system dump datafile 2 block 25962; the datafile number and block come from setp 3
5/ find the datafile and block from dbms_rowid.rowid_relative(rowid),dbms_rowid.rowid_block_number(rowid)
6/alter system dump datafile xxx block xxxx ;which the row in ;
另外附带一下在dump里面看到的数字转换成10进制的算法

（数字位算法）
SQL> select dump(7654321) from dual;
DUMP(7654321)
------------------------------------------------------
Typ=2 Len=5: 196,8,66,44,22

1 row selected.

<指数>: 196 - 193 = 3
<数字1> 8 - 1 = 7 *100^(3-0) 7000000
<数字2> 66 - 1 = 65 *100^(3-1) 650000
<数字3> 44 - 1 = 43 *100^(3-2) 4300
<数字4> 22 - 1 = 21 *100^(3-3) 21

##
SQL> select dump(87654321) from dual;
DUMP(87654321)
--------------------------------------------------------
Typ=2 Len=5: 196,88,66,44,22
1 row selected.
<指数>: 196 - 193 = 3
<数字1> 88 - 1 = 87 *100^(3-0) 87000000
<数字2> 66 - 1 = 65 *100^(3-1) 650000
<数字3> 44 - 1 = 43 *100^(3-2) 4300
<数字4> 22 - 1 = 21 *100^(3-3) 21