Database Link

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

Database Migration from non-CDB to PDB – The Minimal Downtime 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 Minimal Downtime Challenge

When we start to look at a migration from non-CDB to PDB for an important system, regardless of migrating on-prem or to the cloud, reducing the downtime is very important. In this blog post I’d like to highlight the different aspects …

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

Posted on August 5, 2019 by Mike.Dietrich Fallback Single-/Multitenant 2

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 …

Database Migration from non-CDB to PDB – Various Pitfalls

Posted on August 2, 2019 by Mike.Dietrich Flaws and Pitfalls Single-/Multitenant 22

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 …

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

Posted on August 1, 2019 by Mike.Dietrich Flaws and Pitfalls Single-/Multitenant 0

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 …

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

Posted on July 31, 2019 by Mike.Dietrich Flaws and Pitfalls Single-/Multitenant 6

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 …

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

Posted on July 30, 2019 by Mike.Dietrich Flaws and Pitfalls Single-/Multitenant 0

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 …

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

Posted on July 29, 2019 by Mike.Dietrich Flaws and Pitfalls Single-/Multitenant 0

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 …

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

Posted on July 29, 2019 by Mike.Dietrich Flaws and Pitfalls Single-/Multitenant 0

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 …

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

Posted on July 25, 2019 by Mike.Dietrich Single-/Multitenant 11

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.

Photo by Samuel Chan on Unsplash

High Level Overview

Endianness change possible:	No
Source database versions:	Oracle 12.1.0.2

Where does the database link SYS_HUB come from?

Posted on September 24, 2018 by Mike.Dietrich ASM / RAC / GI Flaws and Pitfalls 6

This blog lives a lot from customer’s feedback and updates. And these days, Nicolas Jardot from dbi-services in Switzerland sent me an email asking: Where does the database link SYS_HUB come from? And if he can delete it or if it has any deeper purpose. Neither Google nor MOS reveal a lot of useful information

Where does the database link SYS_HUB come from?

I took my vanilla 18.3.0 database in our hands-on lab and check:

column owner format a5
column db_link format a12
column username format a12
column host format a12

select con_id, owner, db_link, username, host from cdb_db_links;

    CON_ID

Long Identifiers in Oracle 12.2 may cause trouble

Posted on July 3, 2018 by Mike.Dietrich Uncategorized 11

LONG identifiers are one of the key features in Oracle Database 12.2.0.1. But as I learned the other day, you should be a bit careful when you exchange data between different databases. In certain situations, Long Identifiers in Oracle 12.2 may cause trouble.

What are Long Identifiers?

Long identifiers get introduced with Oracle Database 12.2.0.1. For ages, you could name a table or a column or a user or a package in Oracle with only 30 byte length. Hence, naming a table TAB_THIS_IS_MY_TABLE_AND_I_LIK is ok (30 byte – 30 characters) but naming it TAB_THIS_IS_MY_TABLE_AND_I_LIKE_IT is not possible as it requires …

Databases need to be patched to a minimum before April 2019

Posted on March 13, 2018 by Mike.Dietrich Patch Recommendation 7

CORRECTION: After I published this blog post saying “April 2019” my fellow support colleagues changed the alert to “June 2019”. Just saying … the topic itself is still the same.

Simon Pane from Pythian talked to me at OUGN (Oracle User Group Norway) Conference about a recently released alert in MyOracle Support saying “Databases need to be patched to a minimum before June 2019“. He was curious if I know more details. I did some investigation but shortly afterward the MOS Note got updated as well. So here’s a quick summary of things you should be aware of …

Database Link

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

High Level Overview

Database Migration from non-CDB to PDB – The Minimal Downtime Challenge

Database Migration from non-CDB to PDB – The Minimal Downtime Challenge

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

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

Database Migration from non-CDB to PDB – Various Pitfalls

Database Migration from non-CDB to PDB – Various Pitfalls

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

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

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

The Component Pitfall

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

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

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

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

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

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

High Level Overview

Where does the database link SYS_HUB come from?

Where does the database link SYS_HUB come from?

Long Identifiers in Oracle 12.2 may cause trouble

What are Long Identifiers?

Databases need to be patched to a minimum before April 2019

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