Roll forward Physical Stand by Database

[mohith2009]

While performing roll forward of standby database using RMAN Incremental backup SCN there is a step to generate backup of standby control file on primary and then copy it to standby..

What is the purpose of this?

Is it because we do recover using NOREDO clause?

[gandolf989]

I guess you want a copy of the standby controlfile on the standby server and have it current, then you
have it if you need it. However, if you keep the standby current you should not need it. If you are using
Dataguard, you should really turn on forced logging on both the primary and standby databases. This will
prevent nologging operations by forcing Oracle to log everything. If you are doing a large insert and want
to reduce redo you are better off with the append hint rather than no logging.

On the one hand you are saying that you want a standby, then at the same time you are saying that it is
OK not to keep the standby up to date, which takes away the main reason for having a standby. IMHO,
The no logging option is overused. Oracle will log what it wants to log regardless of nologging. You
might as well log everything and have a standby that doesn't need incremental restores.

[mohith2009]

I was reffereing to specific case where in we sync standby from primary using SCN based backup when archivelog goes missing on both primary and standby and you dont have backup of that archivelog.

[gandolf989]

If you have a gap in the archive logs between the primary and standby, you should be
able to restore the needed archive logs on the primary and it should catch up. there is
a command, which I would need to look up, that will force Oracle to try to catch up
applying logs. You can try that also. As long as you leave your standby in apply mode
you don't need to ship a new control file. I'm not sure where you see this step, but
I have never done it.