查了下mos，找到一个文档LOCK ON SYS.SMON_SCN_TIME (文档 ID 747745.1)
本故障的现象：
smon 进程在数据库一启动后就会对smon_scn_time 加一个锁，并且永远都不会释放
根本原因是表和索引不一致。每次删除记录为0条，因此删除操作会一直持续，为了保证表中记录小于
最大映射范围值。
With the Partitioning, OLAP and Data Mining options
[oracle@lixora adump]$ sqlplus "/as sysdba"
SQL*Plus: Release 10.2.0.3.0 - Production on Wed Jul 15 09:25:26 2015
Copyright (c) 1982, 2006, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
----限制smon更新 smon_scn_time 表
SQL> alter system set events ‘12500 trace name context forever, level 10 ‘;
System altered.
---手动清理表记录
SQL> delete from smon_scn_time;
2452 rows deleted.
SQL> commit;
Commit complete.
----关闭限制
SQL> alter system set events ‘12500 trace name context off ‘;
