v$undostat视图没有按照每10分钟进行更新，v$undostat只有1行（one rows）
参考原文：
The V$UNDOSTAT view is not getting updated in every 10 minutes. (Doc ID 1206365.1)
适用于：
Oracle Server - Enterprise Edition - Version: 10.2.0.1 and later [Release: 10.2 and later ]
Information in this document applies to any platform.
症状：
The V$UNDOSTAT view is not getting updated every 10 minutes.
SQL> select BEGIN_TIME,END_TIME, UNDOBLKS from v$undostat;
BEGIN_TIME END_TIME UNDOBLKS
-------------------- -------------------- ----------
21-aug-2010 03:48:44 07-sep-2010 11:02:14 75016989
以上查询只返回1行。
变化：
SQL> sho parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
_in_memory_undo boolean FALSE
_undo_autotune boolean FALSE --->注意此行记录。
undo_management string AUTO
undo_retention integer 3600
undo_tablespace string UNDOTBS1
The parameter "_undo_autotune" has been set to FALSE.
This has disabled automatic undo tuning.
解决方案：
设置"_undo_autotune" parameter to TRUE:
SQL> alter system set "_undo_autotune"=true;
This disables the standard tracking of UNDO statistics in V$UNDOSTAT. You can see only the one row of data as noted in this case.