I have a question here about Oracle data guard.
After performing a switchover, we shutdown the new standby database and startup it.
At this stage, sometimes I find DBA performance in 2 different steps:
startup mount;
startup nomount;
then
alter database mount standby database;
What's the difference between above commands? Could somebody tell me?
Thanks for helping me and forgive me about my English writing.
Best Answer
From the documentation:
startup mount
is the same asstartup nomount; alter database mount
.So there is no practical difference between the two approaches you showed, if the commands are run consecutively (i.e. you are not doing anything else while it is started but not mounted). However, including
STANDBY DATABASE
in the command clearly shows intent, so I think it's generally better to include it, particularly if you're scripting this as part of a switchover process.