AWR报告输出前的参数SnapId有空段无法跨越

做AWR报告，启动AWR，

SQL> @?/rdbms/admin/awrrpt;

Current Instance
~~~~~~~~~~~~~~~~

DB Id DB Name Inst Num Instance
----------- ------------ -------- ------------
2843528876 DEAN 1 dean

Specify the Report Type
~~~~~~~~~~~~~~~~~~~~~~~
Would you like an HTML report, or a plain text report?
Enter 'html' for an HTML report, or 'text' for plain text
Defaults to 'html'
Enter value for report_type: text

Type Specified: text

Instances in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DB Id Inst Num DB Name Instance Host
------------ -------- ------------ ------------ ------------
* 2843528876 1 DEAN dean CENTOS5.5

Using 2843528876 for database Id
Using 1 for instance number

Specify the number of days of snapshots to choose from
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Entering the number of days (n) will result in the most recent
(n) days of snapshots being listed. Pressing <return> without
specifying a number lists all completed snapshots.

Enter value for num_days: 2

Listing the last 2 days of Completed Snapshots

Snap
Instance DB Name Snap Id Snap Started Level
------------ ------------ --------- ------------------ -----
dean DEAN 80 18 Dec 2012 13:22 1

81 19 Dec 2012 14:55 1
82 19 Dec 2012 16:00 1
83 19 Dec 2012 17:00 1

Specify the Begin and End Snapshot Ids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Enter value for begin_snap: 80
Begin Snapshot Id specified: 80

Enter value for end_snap: 83
End Snapshot Id specified: 83

declare
*
ERROR at line 1:
ORA-20200: The instance was shutdown between snapshots 80 and 83
ORA-06512: at line 42

可以看到，选择80——83这段是出错，提示在这段里有shutdown发生，注意看80段下一行是空的，查了资料，才知道原来这意思是这一段有数据库重启发生，所以AWR不能跨越空的段，随后重新选择81——83

成功显示出AWR报告