Downgrade

Database Migration from non-CDB to PDB – The Fallback Challenge

There are several pitfalls when you plugin a non-CDB into a CDB environment. I’d like to highlight some of them – and show you potential workarounds as well. This is part of a series of blog posts to make your migration from non-CDB to PDB a bit smoother.

Database Migration from non-CDB to PDB - The Fallback Challenge

Photo by Sebastian Grochowicz on Unsplash

Database Migration from non-CDB to PDB – The Fallback Challenge

As I work with customers on upgrades and migrations for a very long time, I know how important a proper fallback is.

When you attempt a migration from a non-CDB to PDB, you need to plan …

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When and how should you change COMPATIBLE?

When and how should you change COMPATIBLE?

COMPATIBLE is an almost mystic parameter. It has a default setting for each release. But if you try to find more information what it really does, you won’t be very happy. And in reply to my previous blog post about whether you need to change COMPATIBLE when you apply an RU, I received the following question: When and how should you change COMPATIBLE?

What does COMPATIBLE do?

To find an answer to this question, I consulted the documentation at first. And I found this:

  • COMPATIBLE
    Setting COMPATIBLE ensures that new features do not write data formats or structures
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Downgrade Oracle Restart 12c – Grid Infrastructure only?

Oracle RestartCan you downgrade your Oracle Restart installation from Oracle 12c back to Oracle 11g?

Actually there’s no real direct downgrade supported for Oracle Restart. But of course there’s a way to do it.

Basically it is:

  • Deconfigure Oracle Restart in 12c
  • Configure Oracle Restart in 11g

But wait a minute. It is very important to know if you have upgraded your database already. If that is the case then first you MUST downgrade your database(s) as you can’t manage a higher version Oracle Database with a lower version Clusterware.

So first of all, please downgrade your Oracle database(s) first:…

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