Posts Tagged ‘database administration’

Hi Guys,


Last day I just installed and was thinking to let start with some basics on oracle 12c like what is it? why we need it?

what are the new features available?


So after some research on that (although it was not so hard.. :)) I came to know with some below points.


New Multitenant Architecture
Designed for the cloud, Oracle Multitenant delivers a new architecture that simplifies consolidation and delivers the high density of schema based consolidation, but without requiring changes to existing applications. It’s an option of Oracle Database 12c Enterprise Edition that offers all the benefits of managing many databases as one, yet retains the isolation and resource control of separate databases. In this new architecture, a single multitenant container database can host many ‘pluggable’ databases. Each database consolidated or ‘plugged in’ to a multitenant container looks and feels to applications the same as for existing Oracle databases. Accessing pluggable databases is the same as for existing Oracle databases, and administrators can control the prioritization of available resources between consolidated databases.


Manage Many Databases As One
Consolidating multiple databases means that administrators have fewer databases to manage and the benefits of managing many databases as one can permeate throughout the data center. It is fairly common for IT organizations to manage hundreds, if not thousands of databases, and each of those databases -be they for production, test or development -requires maintenance.


Fewer Patches and Upgrades
Applying patches, patch set updates and product updates to multiple (non-consolidated) databases in order to maintain currency of database releases can be a challenge that only gets more difficult with the number of databases managed. All databases in the data center, regardless of their production, test or development status, are subject to patching and upgrading. Consolidating multiple pluggable databases into a multitenant container can dramatically reduce the amount of patching and upgrade activities required. With Oracle Databases 12c, patches and upgrades are applied at the container level, and not applied to individual pluggable databases. Customers also have the flexibility of creating new patched and/or upgraded container databases and selectively unplugging databases from older container databases and plugging into new upgraded container databases.


Fewer Backups
Every good database administrator regularly takes backup copies of all databases managed in the data center. However, instead of having to backup each separate database in the data center, the new pluggable architecture only requires executing backups at the multitenant container level. This means that database administrators have fewer backups to manage, as each pluggable database in a container database is automatically backed up. However, in the event of any problem encountered with an individual pluggable database, database administrators have the flexibility to perform data recovery operations at the pluggable database level within a container database.

Fewer Standby Databases
Another good example of the benefits of managing many pluggable databases as one is maintaining standby databases. Many Oracle customers use replication technologies such as Oracle Data Guard or Oracle Active Data Guard to maintain complete working copies of production databases by shipping and applying redo logs to a standby system usually in a separate location. With Oracle Database 12c, shipping and applying of redo logs occurs at the container level, therefore every pluggable database consolidated into a container is fully protected from site outages. In addition, customers using Oracle Active Data Guard can make active use of their standby pluggable databases for reporting and other purposes.


Database Resource Management (This one is good..)
While there are undoubtedly many benefits from consolidating multiple databases, customers should consider all aspects of database consolidation. An obvious question to ask is “how can I guarantee the prioritization of resources in this new multitenant architecture?” After all, many of the benefits of managing many database as one will be quickly lost if database applications are continually vying for available system resources, and user performance service levels start to drop off.
Using Oracle Database 12c’s resource management features, database administrators can easily define resource utilization priorities at the pluggable database level. The database server pro-actively monitors database usage to ensure that each pluggable database in a container stays within pre-defined minimum and maximum resource thresholds. For example, at quarter-end, a high priority ERP application can automatically pull system resources from low priority applications in the container to ensure users performance service level remain consistent even at peak demand.


I got all the points from an oracle documentation or you can say oracle white paper, I only have noted which seems important for DBAs to begin with.Click on the link to open it.


and then after installing oracle 12c and it was not a big deal, I thought from where should I start… what is multitenant/container/plugable.

A container is either a PDB or the root. The root container is a collection of schemas, schema objects, and nonschema objects to which all PDBs belong.

Every CDB has the following containers:

  • Exactly one root

    The root stores Oracle-supplied metadata and common users. An example of metadata is the source code for Oracle-supplied PL/SQL packages. A common user is a database user known in every container. The root container is named CDB$ROOT.

  • Exactly one seed PDB

    The seed PDB is a system-supplied template that the CDB can use to create new PDBs. The seed PDB is named PDB$SEED. You cannot add or modify objects in PDB$SEED.

  • Zero or more user-created PDBs

    A PDB is a user-created entity that contains the data and code required for a specific set of features. For example, a PDB can support a specific application, such as a human resources or sales application. No PDBs exist at creation of the CDB. You add PDBs based on your business requirements.


Oracle 12c cloud architecture


You can use the same administration tools for both CDBs and non-CDBs.

For example, you can use the following tools in a multitenant environment:

  • SQL*Plus for command-line access
  • Oracle Enterprise Manager Cloud Control (Cloud Control)

    Cloud Control is an Oracle Database administration tool that provides a graphical user interface (GUI). Cloud Control supports Oracle Database 12targets, including PDBs, CDBs, and non-CDBs.

  • Oracle Enterprise Manager Database Express (EM Express)

    EM Express is a web-based management product built into the Oracle database. EM Express enables you to provision and manage PDBs, including the following operations:

    • Creating and dropping PDBs
    • Plugging in and unplugging and PDBs
    • Cloning PDBs
    • Setting resource limits for PDBs
  • Oracle Database Configuration Assistant (DBCA)

    DBCA enables you to create CDBs or non-CDBs, and create, plug, and unplug PDBs.

  • Oracle Multitenant Self-Service Provisioning application

    This application enables the self-service provisioning of PDBs. CDB administrators control access to this self-service application and manage quotas on PDBs.


Okay this is as quick post to begin with, soon I will post some more points to begin with. Please feel free to post your comments or questions and experts are always welcome with there valuable points.


Thanks & Regards

Nimai Karmakar


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