Oracle无法生成awr报告 ORA-20200错误

生成awr报告的过程中，发生awr报告没有快照，并返回ORA-20200错误。

查看dba_hist_active_session_history发现有数据，判断mmon和mmnl后台进程的问题，故需要重新启动mmon和mmnl后台进程

方法一：

重启数据库

方法二：

启用restricted模式，再立马禁用：

alter system enable restricted session;
alter system disable restricted session;  

alter日志

Stopping background process MMNL
Sat Jan 11 22:07:07 2020
Stopping background process MMON
Sat Jan 11 22:07:39 2020
Background process MMON not dead after 30 seconds
Sat Jan 11 22:07:39 2020
Killing background process MMON
Sat Jan 11 22:08:15 2020
Starting background process MMON
MMON started with pid=19, OS id=2957544
Sat Jan 11 22:08:15 2020
Starting background process MMNL
MMNL started with pid=55, OS id=4960290
Sat Jan 11 22:08:15 2020
ALTER SYSTEM enable restricted session;
Sat Jan 11 22:08:15 2020
ALTER SYSTEM disable restricted session;