Pitfall

Oracle Multitenant: Be aware of the silent COMPATIBLE change

This topic is included in our Multitenant slides for a long time. But whenever I want to point somebody to the blog post, I realize that it’s not on the blog yet. Actually I discussed this topic recently during a customer visit again. It’s time to put it on the blog. When you use Oracle Multitenant: Be aware of the silent COMPATIBLE change.

Oracle Multitenant: Be aware of the silent COMPATIBLE change

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Mixed version environments

When you work with Oracle Multitenant, the sooner or later you will have mixed version environments. This may be CDBs with Oracle 12.1.0.2 or Oracle 12.2.0.1 together with …

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AutoUpgrade may fail when patch ID column is NULL

Monday morning – it’s time to write a new blog post. And actually I will set priorities based on what you reported to me in the past week. This way it may prevent others from hitting the same pitfall. The AutoUpgrade may fail when patch ID column is NULL in REGISTRY$HISTORY.

AutoUpgrade may fail when patch ID column is NULL

Photo by Etienne Boulanger on Unsplash

What is happening?

You start a database upgrade with autoupgrade. But the initial check will fail with a message like this:

AutoUpgrade tool launched with default options
There was an error initializing the patching information for entry upg2

The AutoUpgrade won’t kick …

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RMAN backup generates traces in Oracle 12.2.0.1

RMAN backup generates traces in Oracle 12.2.0.1Oracle 12.2.0.1 seems to be the “tracing” release without further patch or parameter treatments. After posting about MMON unconditional traces in Oracle 12.2.0.1 a day ago, I received a couple of comments either on the blog, via LinkedIn or Twitter regarding other trace facilities in Oracle Database 12.2.0.1. One of them is the case that RMAN backup generates traces in Oracle 12.2.0.1.

And please, very important upfront:
Oracle Database 12.2.0.1 is a very stable and reliable release based on all the customer feedback Roy and I received so far. For instance, when we check for optimizer issues …

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Upgrade to Oracle 12.2.0.1: Check your DEFAULT temporary tablespaces

One of the reasons why I have this blog is simply to stay in touch with smart people using Oracle and telling me about issues I haven’t seen before. Thanks to Tyler Van Vierzen I learned that an upgrade to Oracle 12.2.0.1 may alter the default local temporary tablespace.

Upgrade to Oracle 12.2.0.1: Check your DEFAULT temporary tablespaces

Upgrade to Oracle 12.2.0.1: Check your DEFAULT temporary tablespaces

Tyler did contact me on Twitter:

“Curious if you’ve seen this… Seeing new “local temp tablespace” set to SYSTEM for some users after 12.2 upgrade. But not all. No discernable pattern. Some null (so default to their temp tablespace), some set equal …

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Optimizer Issue in Oracle 12.0.1.2: “Reduce Group By”

Wrong Query Results BugDBAs biggest fears I’d guess are Optimizer Wrong Query Results bugs as usually the optimizer does not write a message into the alert.log saying “Sorry, I was in a bad mood today …”.

The Oracle Database Optimizer is a complex piece – and in Oracle 12c it delivers great performance results. Plus (my personal experience when you know what to do) it is more predictable which I like a lot when changing databases from one to another release. But due to its complexity sometimes we see issues – and sometimes it is necessary to switch off tiny little pieces …

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