Fallback

Database Migration from non-CDB to PDB – Migration with Data Pump

You may have realized that there are a few techniques missing describing how to do a Database Migration from non-CDB to PDB – Migration with Data Pump is one of them. I will explain the most simple approach of going to Single- or Multitenant. It isn’t the coolest – and it isn’t very fast as soon as your database has a significant size. But it is not complex. And it allows you to move even from very old versions directly into an Oracle 19c PDB – regardless of patch levels or source and destination platform.

Database Migration from non-CDB to PDB – Migration with Data Pump

High Level Overview

Endianness change
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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 … [ Read more ]

Database Migration from non-CDB to PDB – Various Pitfalls

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 - Various Pitfalls

Photo by timJ on Unsplash

Database Migration from non-CDB to PDB – Various Pitfalls

In all the previous blog posts of this series I tried to explain specific pitfalls, and how you can workaround them. This article is meant to collect the “leftovers”, the minor issues and pitfalls which you may not … [ Read more ]

Database Migration from non-CDB to PDB – The Patch Level Pitfall

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 Patch Level Pitfall

Photo by Piron Guillaume on Unsplash

Database Migration from non-CDB to PDB – The Patch Level Pitfall

When you consolidate on a larger scale, it is very likely that you have different patch levels in your database environments. But when you attempt to plugin a non-CDB into a CDB, you may see … [ Read more ]

Database Migration from non-CDB to PDB – The Component Pitfall

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 Component Pitfall

Photo by Brett Jordan on Unsplash

The Component Pitfall

With component we mean the database component which you can find in DBA_REGISTRY – or CDB_REGISTRY. When Multitenant became available over 5 years ago, a decision had been made to make all options/components mandatory in a container database. This decision had to … [ Read more ]

Database Migration from non-CDB to PDB – The Time Zone Pitfall

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 Time Zone Pitfall

Photo by Allef Vinicius on Unsplash

Database Migration from non-CDB to PDB – The Time Zone Pitfall

Interestingly, there is no issue with different time zone settings within a single CDB. Your CDB$ROOT can be on DST V.32 whereas a PDB you plugin can be already on DST V.33. But only [ Read more ]

Database Migration from non-CDB to PDB – The COMPATIBLE pitfall

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 COMPATIBLE pitfall

Database Migration from non-CDB to PDB – The COMPATIBLE pitfall

When you migrate your non-CDB to PDB, in most cases the COMPATIBLE setting of the non-CDB will be lower than the setting of the receiving CDB. But still in this case you may see warnings. I will explain how to deal with … [ Read more ]

Database Migration from non-CDB to PDB – Typical Plugin Issues and Workarounds

In the previous blog posts I showed different approaches on how to migrate your database on a same Endianness platform into Multitenant. Whether you prefer to upgrade first or plugin first is up to you. I recommend upgrading first as this allows you a seamless fallback. But regardless of which approach you prefer, you may take care on potential pitfalls. Hence, this blog post is about Database Migration from non-CDB to PDB – Typical Plugin Issues and Workarounds. It may not be complete when I publish it and I may extend it later on. Let me know if you have … [ Read more ]

Database Migration from non-CDB to PDB – Clone via NON$CDB, upgrade, convert

The third option for plugging in a non-CDB is called Database Migration from non-CDB to PDB – Clone via NON$CDB, upgrade, convert. As I showed already in this blog post a while ago, your source must be at least an Oracle 12.1 database. And this technique can be used also only for same-Endianness migrations but does not apply if you’d like to migrate from Big to Little Endian. If your source database matches already the receiving CDB, no upgrade is necessary.

Database Migration from non-CDB to PDB – Clone via NON$CDB, upgrade, convert

Photo by Samuel Chan on Unsplash

High Level Overview

Endianness change possible:
No
Source database versions: Oracle 12.1.0.2
[ Read more ]

Database Migration from non-CDB to PDB – Plug in, upgrade, convert

This is my next blog post about Database Migration from non-CDB to PDB – Plug in, upgrade, convert. But what is different from the previous one? And why is it necessary? Since Oracle Database 12.2.0.1 you can plugin a non-CDB at first, the upgrade and convert it. And I’ll show you this technique here.

Database Migration from non-CDB to PDB – Plug in, upgrade, convert

Photo by Dan Freeman on Unsplash

High Level Overview

Endianness change possible: No
Source database versions: Oracle 12.2.0.1 or newer (or 12.1.0.2 when CDB has shared UNDO)
Characteristic: Plugin into CDB first
Upgrade necessary: Yes, after plugin
Downtime: Plugin, copy (optional), upgrade and noncdb_to_pdb.sql
Minimal
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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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Fallback Strategy: Partial Offline Backup

Oh, I think it took us years to get rid of recommendations in MOS notes saying before this or that change you must take an offline backup. These recommendations dated back to times where not almost everybody was using RMAN for online backups. But the times have changed. Still, there are situations where the “Offline Backup” word can be mentioned. And in this blog post I will describe a Fallback Strategy: Partial Offline Backup.

Usage Scenario

This method will only protect you against failure during an upgrade.

First of all, Offline Backup sounds really brutal and old-fashioned. … [ Read more ]

Upgrade and Migration Office Hours on April 19, 2018

Upgrade and Migration Office Hours on April 19, 2018It’s time for the next Office Hours session with the Upgrade Development Team. The Upgrade and Migration Office Hours on April 19, 2018 features the topic “Fallback Strategies“. Roy will prepare a short slide intro. And afterwards we’ll happily take your questions.

What are “Office Hours”?

This is a new interactive format we really like. Several groups in Oracle schedule Office Hours sessions. Roy and I held our first Office Hours session on February 21, 2018 for a full hour trying to answer your questions regarding database upgrades and migrations live and directly.

How do you sign up?

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Fallback Strategies with Full Transportable Export/Import

Fallback Strategies with Full Transportable Export/ImportI received an interesting question about how to implement Fallback Strategies with Full Transportable Export/Import several times within the past weeks. So it may be a good idea to showcase some possible scenarios.

Full Transportable Export/Import is an Oracle 12c feature which allows you to do a transportable tablespace migration but Data Pump will take away all the manual steps with only one command. You may need to have markers to revert to in order to avoid restarting the entire operation from scratch again.

And there are some special behaviors to know about, at first with Full Transportable Export/Import but … [ Read more ]

Fallback Strategy: Flashback Pluggable Database

Fallback Strategy: Flashback Pluggable Database in Oracle 12.2Since Oracle Database 12.2 an important feature works now for pluggable databases as a Fallback Strategy: Flashback Pluggable Database in Oracle 12.2. This was missing in Oracle Database 12.1.

Actually I missed this feature a lot as I use “Flashback” almost everyday. And you could only rewind the entire deployment with a FLASHBACK DATABASE command.

Fallback Strategy: Flashback Pluggable Database

Fallback Strategy: Flashback Pluggable Database in Oracle 12.2Actually having the possibility to flashback a pluggable database without effecting the other PDBs is really important. Did you ever want to try out what happens if you TRUNCATE TABLE SYS.PROPS$? Give it a try – but set a [ Read more ]

Guaranteed Restore Points as Fallback Method

Thanks to the great audience yesterday in the Upgrade & Migration Workshop in Utrecht. That was really fun and I was amazed by our new facilities (and the  “wellness” lights surrounding the plenum room’s walls).

And another reason why I like to do these workshops is that often I learn new things from you 🙂 So credits here to Rick van  Ek who has highlighted the following topic to me. Yesterday (and in some previous workshops) I did mention during the discussion about Fallback Strategies that you’ll have to switch on Flashback Database beforehand to create a… [ Read more ]

Upgrade Fallback: Offline Backup??

When me an Roy talk about Fallback Scenarios in our Upgrade Workshop we cover first issues happening during the upgrade and second issues happening a few days (hours, weeks) after the upgrade.

One of the fallback options for issues encountered during the upgrade is to take an offline backup. Ok, not a complete offline backup of your 24TB database. Take all data tablespaces into read-only mode, then shutdown the database. Take a backup of all datafiles for SYSTEM, SYSAUX and UNDO plus the controlfiles plus the redologs. TEMP files are not a requirement as you could … [ Read more ]