RAC环境alert日志报错Drop transient type: SYSTP2JW0acnAurDgU1sBqMBryw==的排查

近期日常检查中，发现一个用户的RAC环境出现有报错：
*** 2022-02-22 19:34:58.672
         Drop transient type:   SYSTP2JW0acnAurDgU1sBqMBryw==

查询ORACLE MOS网站，有文档说明的类似问题：Receiving ORA-21780 Continuously in the Alert Log and SMON Trace Reports "Drop transient type". (Doc ID 1081950.1)。

简单解释为SMON在清理这些对象时出现问题，仅在RAC环境出现；文档中给出两种处理方案，如下：

There are two possible solutions.

Solution #1
------------

Step 1
Make sure you have a good full backup.

Step 2
spool obj.lis
alter session set nls_date_format='DD-MON-YYYY HH24:MI:SS';
set pagesize 1000
select o.* from obj$ o, type$ t
where o.oid$ = t.tvoid and
bitand(t.properties,8388608) = 8388608 and (sysdate-o.ctime) > 0.0007;
spool off

Step 3
Find the object owner:

Step 4

Drop the objects.
DROP TYPE "SYSTPf/r2wN4keX7gQKjA3AFMSw==" FORCE;



Solution #2
------------

You can prevent SMON to cleanup transient types by setting event 22834 like below.
However, this can cause transient types to increase.

SQL> alter system set events '22834 trace name context forever, level 1';
System altered.

To turn off:

SQL> alter system set events '22834 trace name context off' ;
System altered.