INSTANCE_ABORT_DELAY_TIME

12.2新参数
指定instance在将要发生abort（such as when a fatal process dies or an unrecoverable instance error occurs）时延时多少秒再abort，这段时间可以留给DBA处理问题
此参数不对用户执行shutdown abort有效
RAC所有实例此参数要设置相同值

Note that since the instance is in a fatal state, the DBA should not be too ambitious with the actions taken because some processes and/ or resources may be corrupted or unavailable, making complex actions impossible. 
Oracle does not guarantee what it is possible when an instance is in this state. 
A message is written to the alert log when the delayed abort is initiated. The value will not apply in the case of PMON death.

The larger the specified value, the longer the instance stays up, and the potential increases for other problems to occur. 
If you set this parameter, Oracle recommends setting it to a value between 0 and 60.