dump轉儲undo segment header block回滾段頭塊小方法

/*******產生一個事務*********/
SQL> insert into t_ts values(1);

1 row created.

/*******查詢上述事務對應的回滾段頭及檔案******/
SQL> select segment_name,header_file,header_block from dba_segments where segment_name=(select name from v$rollname where usn=(select xidusn from v$transaction));
 
SEGMENT_NAME                                                                     HEADER_FILE HEADER_BLOCK
-------------------------------------------------------------------------------- ----------- ------------
_SYSSMU6_821479913$                                                                        3          208

/*******轉儲回滾段頭********/
SQL> alter system dump datafile 3 block 208;
 
System altered

/********另一處方式轉儲回滾段頭*******/
SQL> alter system dump undo header '_SYSSMU6_821479913$';
 
System altered

/*****具體事務涉及的undo block請參看v$transaction*********/