Oracle 12c Database New Features - Pluggable Database - Video 1

Oracle 12c Database New Features - Pluggable Database - Video 1

1. Pluggable Database

* Oracle 12c introduces a new feature called 'Pluggable Database'. Here Oracle Metadata and user data are totally separated into two sections. One is Container DB (or CDB) which will hold Oracle Metadata. The other is Pluggable DB (or PDB) which will hold user data.

How does a Pluggable Database work?

In the regular database, Oracle's metadata and user's application data are integrated. For beginners, Oracle Metadata is the data that is present when you install a new Oracle Database (without any sample schemas). Even though it can be called as an empty database, it still has data provided by Oracle. This data is needed by the database to function. For example, the objects owned by SYS, SYSTEM are mostly metadata.

Then user data is entered into that database. They will go under multiple user schemas. Now the database is being used by the users.

Now a situation arises so that we need to create another database on the same server. Why? Let us say that you need to provide data to two clients. And you don't want one client to other's data. And your data is contained in an extensive set of application schemas.

In this case, making a copy of those applications schemas into a different set of names and making them reside in the same database is very difficult.

So, you provide two separate databases. This also ensures that there is no security violation.

So, we install another new database, which comes with Oracle Metadata. Then we load the user data. In this method, which is currently being used (Year 2013), there will be a need for more memory for both the database instances. There will be two SGAs, two sets of smon, pmon and other background processes running.

Then if we need to copy one database to another, we need to rely on extensive procedures which includes exporting the data from the source database first, then removing the data at the target and then finally loading the data in there. After that, we need to take care of the user security and object privileges etc.

So, if you want to provide data for multiple tenants, that is multiple clients, then with the current set of features (till Oracle 11g), we have to create multiple databases. That is, one database for one client. In otherwords, there is no multi-tenancy.

Multi-Tenancy is becoming an important requirement in cloud infrastructure, these days. You would like to have the ability of providing data to multiple clients from the same database system with full confidence in security.

This can be achieved in Pluggable Database.

In a Pluggable Database, Oracle basically separates its metadata entirely from the user data. Metadata is stored in a section called Container DB. Then the user data are stored in Pluggable DBs. It also stores user metadata in the Pluggable DB.

By the way, what is user metadata? For example, earlier, the list of user accounts that exist in a database is tightly inegrated with Oracle Metadata. Now, with the separation of Container DB and Pluggable DB, the user accounts must exist in the Pluggable DB. So, the Pluggable DB not only contains user data, but also some user metadata.

So, what are the benefits?

* Multi-Tenancy - We can bring in two Pluggable DBs under one Container DB. Both will be totally segregated, but yet controlled by one instance. This is an important feature for SaaS (Software as a Service) platforms, Cloud, On-Demand and Vendor Managed Application solutions.

* Easy cloning/copying. Now the cloning and copying the databases across servers would be much easier. Just clone a Pluggable DB and plug-it-in in a different server.

* Very easy upgrades and patching.

[manideep]

Excellent video. He is straight to the point and very clear. Thanks Man !

[jaganreddy]

Hi Sam,
Very good presentation. Appreciate this Oracle 12C pluggable architecture. So finally Oracle is catching up with other DBMSs have for 20+ years. This concept of master database TO individual databases under one instance has been the structure with Sybase, SQL Server, DB2, even MySQL from day one of their operations. I have quick question: What tool did you use to create presentation that allowed to write easily?

[mojofullyalive]

Hi Sam, Thanks for very descriptively in a simpler and easier way in a layman language.
Good one.

[timallen]

Very well discussed. I hope it is just that easy

[padff]

Thanks Sam, cannot wait until it's introduced here in my company!

[robertsonhp]

Precise for beginners of 12C. Does this architecture not compromise on CDB high availability as well CDB memory and resource contention

[zeeitechriver]

Great explanation and especially thanks for the nicely written description of the video.

[nvasudeva]

concepts very nicely explained... although some info about multiple db version getting housed in pluggable db would have been nice to have in this video. Still, i would say u did a good job in explaining stuff.

[ragunathms]

your presentation skills are just gave a lot of information on pluggable databases....thanks..:)

[nkanike]

HI Sam,
Thanks for explaining the Multi tenant database. Very informative.
Regards,
Narendra

[regendidi]

Lol!! I like that. You are quite right there. Things should start to get interesting from both management and competition perspectives.

[rajwardhan]

its pretty amazing..thank you for this precious information

[RashmiSingh-vssj]

Very nicely explained...thank you sam!!

[vijaytak]

crystal clear explanation sam! kudos!

[kamaljoshi]

Hello Sam,
Thanks for sharing it in a lucid manner. After seeing ur video, got to know that from 12C, we would have single SGA to manage all pluggable DB. So, I am also curious to know how oracle would manage SGA size for each database as the size of SGA is based on the load of every DB & more allocated space to SGA can also degrade DB performance.. Plz also shade your thoughts on my concern...

[binaryconsole]

Well explained, but the mouse pointer is disturbing a lot, please think of using small pointer in future videos. But your video is very useful.

[deepakssi]

Sam thanks a lot for the excellent concept presentation 

[kiran]

hi sam,

way of presentation is excellent. i also wants to share some concepts like this. could you please let me know which software you used to write something on the picture.

thanks

[gugun]

Sam, will there be performance issues if we are using multiple PDB's ?

[pinusingh]

good intoduction to 12c, can you please confirm if CDB and PDB will have only 1 instance running from CDB and changing 1 DB parameter in CDB will effect all PDB

Regards, Mayank (DBA)