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A change in Oracle 12.2 and 19c with MV Refresh Stats Collection

It’s not easy for me to put the topic into a searchable title for this blog post. The feature or change I will write about today came in actually with Oracle Database 12.2.0.1. But since many of you will move directly from Oracle 11.2.0.4 or 12.1.0.2 to 19c, the Long Term Support release, it may affect you as well. So let me explain a change in Oracle 12.2 and 19c with MV Refresh Stats Collection.

 

A customer story

The local Support team asked me a few weeks ago whether I have heard …

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You may need a one-off for DBMS_OPTIM_BUNDLE in 19.10.0

It’s been a while since I blogged about the DBMS_OPTIM_BUNDLE – and to me, the package is still sort of a mystery. Ideally you can least and enable or disable behavior changing optimizer fixes per RU. And in Oracle 19.10.0, you will find a new surprise. So You may need a one-off for DBMS_OPTIM_BUNDLE in 19.10.0.

You may need a one-off for DBMS_OPTIM_BUNDLE in 19.10.0

Photo by Jonas Denil on Unsplash

Quick Recap

Just in case you haven’t dealt with DBMS_OPTIM_BUNDLE yet or for a while, a quick recap.

With this procedure, you can list the available patches to turn on or off at will:

SQL> set serveroutput 
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Automatic Maintenance Jobs are enabled after upgrade

This is a strange behavior – but it seems as automatic maintenance jobs are enabled after upgrade. A customer (thanks Naveen!!) sent me an email the other week asking if there’s a flag in DBUA to prevent this enabling as on some of their databases the automatic maintenance jobs are disabled on purpose.

Automatic Maintenance Jobs are enabled after upgrade

It sounded kind of strange to me – and my first test was to use the catctl.pl instead of the DBUA.

First of all I did check the status of the Automatic Maintenance Jobs in my 11.2.0.4 database:

SELECT client_name, 
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When you upgrade, disable the Data Guard Broker

A customer of mine hit an issue recently when upgrading to Oracle Database 12.2.0.1. They did everything correctly but received a ton of issues from the Data Guard Broker. A rule says: When you upgrade, disable the Data Guard Broker. But I can’t blame the customer as this “rule” is well hidden in the documentation.

When you upgrade, disable the Data Guard Broker

First of all, the Data Guard Broker is required if you would like to administer your databases in Oracle Cloud Control. Otherwise you can’t switchover or failover within Enterprise Manager. But once you approach a database upgrade …

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DBMS_OPTIM_BUNDLE – only available in Oracle 12.1.0.2 – or not?

DBMS_OPTIM_BUNDLE - only available in Oracle 12.1.0.2The DBMS_OPTIM_BUNDLE package got introduced with the April 2014 Exadata 11.2.0.4 Bundle Patch. And it got introduced for all Oracle 12.1.0.2 databases with the April 2017 Bundle Patch (BP). DBMS_OPTIM_BUNDLE is only available in Oracle 12.1.0.2.

Addition March 6, 2018:
See the updated blog post about DBMS_OPTIM_BUNDLE available in Oracle 12.2 and 18c onwards.
https://mikedietrichde.com/2018/03/08/dbms_optim_bundle-package-oracle-12-2-18c/

For more information on this package on Exadata in Oracle 11.2.0.4 you may look at:

Purpose of DBMS_OPTIM_BUNDLE package in Oracle 12.1.0.2

The package got introduced to enable module bug fixes which …

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Disable Transparent Hugepages on SLES11, RHEL6, RHEL7, OL6, OL7 and UEK2 Kernels

This blog post is not related to database upgrades and migrations. But still I think it is very useful for many customers operating on modern Linux systems.

Recommendation 

Support just published an ALERT strongly recommending to disable Transparent Hugepages on Linux systems. And the below information does not apply to RAC systems only but also to single instance environments.

Which Linux Distrubutions/Kernels are affected? 

  • SLES11
  • RHEL6 and RHEL7
  • OL6 and OL7
  • UEK2 Kernels

What are the Issues? 

I’m quoting MOS Note: 1557478.1 (ALERT: Disable Transparent HugePages on SLES11, RHEL6, RHEL7, OL6, OL7 and UEK2 Kernels):

Because Transparent HugePages are

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