Some very important MOS Notes when you upgrade and patch

Today, I would like to publish only a short blog post with some hints to MyOracle Support (MOS) notes we find quite helpful. The idea of all these notes I will list below is to help you finding the right patches before you upgrade or patch to Oracle 19c. So see our collection of Some very important MOS Notes when you upgrade and patch below.

Why do you need patch bundles?

At first, it is always our recommendation to upgrade to the most recent Release Update (RU). This is currently Oracle 19.11.0 while I’m writing. But in case you read this in a few months, it may be 19.12.0 or 19.13.0 or even newer.

And here comes our first MOS Note tip into play – the Download Assistant. With this note you quickly access the newest patch bundles for the Database and for Grid Infrastructure.

In addition, this MOS Note gives you an overview on the patching itself but lists also the dates and other information about patch availability:

Are there Known Issues with this RU or RUR?

In every Release Update’s (and Revision’s) README there is a link to Known Issues. Please don’t forget to check it. It is typically listed under %. Critical Issues. In the 19.11.0 RU case for example, find it here:

In addition, in the README itself under the same chapter 5, Critical Issues, you may find other issues happening during patch apply.

But why do you need extra patches?

Now the question you may ask yourself: When I already used the most recent Release Update, for instance at the moment 19.11.0, why do I need extra patches on top of it?

There is always a chance that an important fix (or more than one) are not present in this Release Update.

  • The fix didn’t make it into the RU because of code freeze timelines
  • The fix is not eligible  for a patch bundle which has to be “RAC Rolling” – this is often the case for fixes changing the common API – Data Pump or Real Application Testing fixes are common examples
  • The fix is scheduled for inclusion into a later Release Update
  • The issue is simply too new or got introduced with this Release Update – we call this a regression

Therefore, you may consider some extra sources. And currently those are not linked together in all cases.

Let me start with the first one as it lists the most critical issues:

Applying fixes listed in this MOS note is almost a must before you patch or upgrade.

But there are more notes to take care on.

Performance, Wrong Results and SPM

Of course, everybody wants to learn about specific performance issues, wrong result topics and not to forget, SQL Plan Management.

Grid Infrastructure

In case you use Grid Infrastructure, this note is coming to my mind as something you may want to check as well:

Data Pump

In addition, Sven recommended this note for Data Pump:


And another recommendation by Sven for those of you using Oracle GoldenGate:

You know other important notes?

Of course, we don’t claim that this is a complete collection. Nor do we dictate you’ll have to look at all of them. But if you have tips for other very important notes to check before you upgrade or patch, please let us know via the comments section.

And just on the side, there is a reason why I didn’t include MOS Note: 2539751.1 – Patches to apply before upgrading Oracle GI and DB to 19c or downgrading to previous release. In our opinion, this note is very misleading, especially regarding the database patches. And it hasn’t been updated for over a year.

Summary of all links listed in this blog post


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