ORA-38855: cannot mark instance string (redo thread string) as enabled

文档解释

ORA-38855: cannot mark instance string (redo thread string) as enabled

Cause: The standby switchover or failover operation failed because it needs to mark an instance (redo thread) as enabled. However, it had less than 2 online redo logs, which prevented it from being enabled.

Action: Add more logfiles to the specified instance and retry the command.

ORA-38855错误(不能将实例字符串（重做线程字符串）标记为启用)，通常指实例(instance)的选项无法被修改，以使重做线程(redo thread)具有可用状态。

官方解释

常见案例

一般处理方法及步骤

1、检查实例的配置参数，确保正确配置。

2、重启数据库实例，尝试重置其状态，以重新启用重做线程。

3、检查重做线程日志，检查可能的失败原因。

4、更改实例状态，并尝试给实例添加重做线程。