Hey all,
I've been working on a plan to get our databases upgraded from 11.2.0.3
to 12.1.0.2. Most of the planning is relatively straightforward, except
for one DB. It has active data guard to a physical standby. I've
managed to work out how to properly upgrade it, despite the
"instructions" at
https://docs.oracle.com/database/121/SBYDB/upgrades.htm#SBYDB4931 ;
The part I can't figure out is how to rollback the upgrade in a timely
manner, should it be needed. The easiest is to restore from backup and
recreate the standby, but that will take several hours.
https://mikedietrichde.com/2017/08/29/fallback-strategy-flashback-to-guaranteed-restore-points/
says to use Flashback guaranteed restore points, but there's no mention
of how this should work with a standby. No problem, I can figure that
out. The restore point on the primary doesn't exist on the standby, but
I can get the SCN, subtract 2 (as per MOS articles), then FLASHBACK
STANDBY DATABASE TO SCN nnnn. That produces "ORA-38726: Flashback
database logging is not on.", since, well, flashback isn't on. It's not
needed for the primary -- is that a restriction on the standby?
Anyone know 1) where this might be documented, and 2) how one might go
about planning a time-sensitive upgrade fallback for an ADG setup?
I was thinking that instead of relying on the SCN for the Flashback on
the standby that maybe I'd need to setup a separate guaranteed restore
point (with MRP stopped) before the primary one is created. I've been
testing various scenarios, but as it takes >30 minutes to set up each
scenario, I thought I should ask here to possibly save me a couple of
days of fun.
Thanks!
Rich
