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.