-----Original Message-----
From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Alex Ignatov
Sent: Thursday, July 28, 2016 10:59 AM
To: Rakesh Kumar <rakeshkumar464a3@gmail.com>
Cc: PostgreSQL General <pgsql-general@postgresql.org>
Subject: Re: [GENERAL] Uber migrated from Postgres to MySQL
On 28.07.2016 17:50, Rakesh Kumar wrote:
> On Thu, Jul 28, 2016 at 10:38 AM, Alex Ignatov <a.ignatov@postgrespro.ru> wrote:
>
>> Sorry, what? You can rollback to previous version of software what you had.
>>
>> https://docs.oracle.com/cd/E11882_01/server.112/e23633/downgrade.htm#
>> UPGRD007
> Not so fast. This requires the db to be set in compatibility mode of
> the lower version. Once that is removed, no downgrade is possible.
>
> Also starting from Oracle 12 this downgrade option has been removed.
> That is, you can't upgrade in-place from Or 11 to 12 and then
> downgrade back. The only supported way is the restore from an old
> backup (which is true for all products). I don't work in Oracle, but
> got this clarified by someone who is an Oracle dba.
>
>
Not true -
https://docs.oracle.com/database/121/UPGRD/downgrade.htm#UPGRD007
About compatible params you are right but downgrade is possible from 12c.
Alex Ignatov
Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
_____________________________________________________________________________
Alex, documentation you point to just proves what Rakesh said:
"For supported releases of Oracle Database, you can downgrade a database to the release from which you last upgraded.
Forexample, if you recently upgraded from release 11.2.0.4 to Oracle Database 12c, and you did not change the
compatibleinitialization parameter to 12.1 or higher, then you can downgrade to release 11.2.0.4."
So, you can downgrade only if you didn't "activate" newer feature (didn't compatibility to higher version).
But then, what's the point in upgrading (I know, there are some like bug fixes, etc...), if you aren't going to use
newerfeatures.
Regards,
Igor