Deprecation of Non-CDB Architecture in Oracle 12c
January 26, 2015 26 Comments
Back in July 2013, Oracle released the latest version of its flagship database product, Oracle 12c. Among the usual fanfare was information about a number of new options – including one known as Multitenant. With the Multitenant option, databases use a new architecture which features a container database (or CDB) which in turn contains one or more pluggable databases (or PDBs). Use of Multitenant requires a licence – which at the time of writing retails at $17,500 per processor (perpetual) plus 22% per annum for support.
This post is not intended to discuss the way Multitenant works – if you want to read more about it, Tim has a great set of articles about Multitenant here. But keep in mind that you can choose to install the Multitenant feature or not. If you do install it, you can create a single PDB within your CDB without requiring the license. As soon as you use more than one PDB the license is required.
What I want to talk about is Oracle’s attitude to its customers and what seems to me to be breathtaking arrogance. Personally I can think of three very good reasons why I might not want to use the single PDB within a CDB configuration which does not require a Multitenant license:
- Multitenant requires additional configuration and the use of new administrative commands, which means re-writing admin procedures and re-training operations staff
- Multitenant is an entirely new feature, with new code paths – which means it carries a risk of bugs (the list of bug fixes for the 18.104.22.168 patchset contains a section on Pluggable/Container Databases which lists no fewer than 105 items)
- With the Multitenant option installed it is possible to trigger the requirement for an expensive set of licenses due to human error… without the option installed this is not possible
So it seems to me that, while Multitenant might be an interesting and useful new feature to evaluate, it is not something that I would want to be forced into using on production environments just yet. As always, people who manage production environments are conservative in their attitude to risk.
And that’s why I’m surprised to see this deprecation notice in the 12.1 documentation:
The non-CDB architecture (i.e. the old way of building a database without CDBs and PDBs) has been deprecated in 12c and “may be desupported or unavailable” in later releases of Oracle Database. In other words, you need to change to using the CDB and PDB configuration now, even if you do not plan to purchase the Multitenant option.
It would be nice to have the choice, wouldn’t it?
Deprecated versus Desupported
OK so first let’s just remember that the term deprecated does not mean the same as the term desupported. We can dip back into the documentation to define these two important terms:
“By deprecate, we mean that the feature is no longer being enhanced but is still supported for the full life of the 12.1 release. By desupported, we mean that Oracle will no longer fix bugs related to that feature and may remove the code altogether.”
– Oracle Database 12c Upgrade Guide
It seems that Oracle will still support the use of non-CDB databases and will continue to do so for the lifetime of the 12.1 release. But, if you were designing a new system right now, it would take some confidence to choose a configuration which is deprecated and already living on death row.
And there’s more. The deprecation notice says there are some features that still do not work with the CDB architecture – and that if you want to use these you should use the deprecated non-CDB architecture. The list of features which are restricted or not available includes Automatic Data Optimization, Heat Maps, DBVERIFY and Flashback Pluggable Database (you can see the complete lists here for 22.214.171.124 and 126.96.36.199).
So we can add a fourth reason to our list of three drawn up earlier:
Now, given that I think all four reasons stated here are good enough to stand up on their own, what does this say about Oracle’s decision to deprecate non-CDB architectures?
You can draw your own conclusion, but I can’t help see it as arrogance on Oracle’s part as they force customers to use a specific new configuration with little regard for how it affects their operations. At worst, I don’t like being forced into changes by the vendor (to whom customers pay large amounts of money) while at best I would at least expect them to get all the features working before forcing the issue…
Update – 18 February 2015
Since I published this article back in late January I’ve had a lot of comments – both here and on Twitter. Some agree with me, some disagree – and unsurprisingly many of the latter are Oracle employees. One particular Oracle employee took to his corporate blog to post a four-part response!
One of those responses was in regard to my concern that, since it seemingly cannot be unlinked, customers may be able to inadvertently trigger usage of the Multitenant feature and thus incur an expensive and unexpected license bill. [I have no knowledge that this has ever happened, I am merely concerned that it may be possible.]
I’d like to quote the following response from our friend on the Oracle blog (his own opinion, not the views of his employer) who is apparently looking to rubbish that concern. I have placed the most enlightening part of the text in bold for emphasis:
This bit of FUD is silly. First of all, this risk already exists with various features of the Oracle database. For example, many of the OEM packs can be inadvertently used without a license as could several of the views in the database itself. Partitioning is another example that comes to mind. Often it’s installed in a database but it’s use requires a license.
So, how is this any different? Well, it’s not. Simply put, this is an argument for enterprise compliance auditing/management.
I hope this convinces you more than it convinces me.