more about _allow_error_simulation

_allow_error_simulation在10g以后常用于配合adjust_scn事件来提升SCN应对ora-00600 [2662] askmac.cn

当然该参数最早被设计出来不是为了仅仅这一个目的的，其被设计出来做为一些隐藏参数和选项的开关，以便控制调用oracle事件来测试各类错误。其默认为false，即例如10015 trace name adjust_scn这类事件不会实际生效，askmac.cn

552438.1 How To Adjust the SCN using parameter _MINIMUM_GIGA_SCN @
Formerly this note mentioned adjust_scn of event 10015 but no longer. An
event is sometimes not helpful because some types or issues do not allow
Oracle to reach the point of using the event, thus the change. Note 552438.1
requires a calculation best resolved by support.

As of 10g, the parameter _ALLOW_ERROR_SIMULATION=TRUE may be set.