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Oracle Database 12c New Features - DBA

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Let us discuss new features of Oracle Database 12c Release 1.(12.1). Oracle says there are 500+ new features incorporated in 12c. We will see very few which are going to make a change in database world.

Multitenant architecture:

Pluggable databases (PDBs) and Container Database (CDB) is the new architecture for 12c.We can have may PDBs in a single database occurrence (CDB).PDBs are just like ordinary 11g or 10g databases. This architecture reducing the total cost of operations and improving the functionalists.It has other benefits like it is very easy to clone the database and new database creation.By doing one patching all PDBs will get upgraded. We can patch a PDB by unplug and plug in to different CDB.
  • There is one set of background processes shared by the root and all PDBs. 
  • There is a single redo log and a single control file for an entire CDB 
  • There are single SGA shared by all pluggable databases. However, we can determine SGA consumption by all containers i.e, root and PDB 
  • We can monitor PGA usage on PDB by PDB basis. 
  • There is one active undo tablespace for a single-instance CDB. For an Oracle RAC CDB, there is one active undo tablespace for each instance. Only a common user who has the appropriate privileges and whose current container is the root can create an undo tablespace 
  • There is a separate SYSTEM tablespace for the root and for each PDB. 
  • There is a separate SYSAUX tablespace for the root and for each PDB. 
  • There is one default temporary tablespace for the entire CDB. However, you can create additional temporary tablespaces in individual PDBs. One active undo tablespace is needed for a single-instance CDB, or one active undo tablespace is needed for each instance of an Oracle RAC CDB. 
  • You can specify a separate default tablespace for the root and for each PDB


Far sync standby database

A Far Sync Standby Database is a cascading Standby Database which acts as a Redo Log Repository for a Terminal Database. It does not contain any Datafiles. Only Log Transport Services are active on a Far Sync Standby Database.The Advantage of a Far Sync Standby Database is that it can be a local ArchiveLog Repository for the Primary Database acting in Maximum Protection Mode where the Physical or Logical Standby Database can be on a far remote Site.
New Options for Cascaded Standby Databases

In 12c it is possible to cascade a Standby Database in Real-Time, ie. the first Standby Database can send Redo from the Standby RedoLogs to the cascaded Standby Database. The Data Guard Broker now supports Cascaded Standby Databases, too.

SYSDG Administration Privilege

New sys role for dataguard SYSDG and it is possible to grant the SYSDG-Privilege to a User in order to perform Data Guard-related Operations. The full SYSDBA-Privilege is not required any more to manage a Data Guard Environment, but can still be used.

Online Movement of Online Datafiles

We can now move Online Datafile without stopping Managed Recovery and manually copy and rename Files. This can even be used to move Datafiles from or to ASM, It is in standby what about production?? Yes it is possible to move the datafiles in production also.

Multitenant Database Support

Data Guard supports Physical Standby Database for a Multitenant Database, of course


Recover table option

The RECOVER TABLE command is a new feature in 12C that allows point in time recovery of a table or a table partition.
The table is recovered into an auxiliary instance and there is the option to import the recovered table into a new table or partition using REMAP option or create the expdp dump of the recovered table only, for import at a later time of your choosing.
In 10g what we did when we need to recover only one table using RMAN? We restored in a UAT and taken export and import it back. Same concept is using here by RMAN. It will create an auxiliary database, then restore the tablespace and take export and import.


Multi-Process Multi-Threaded Oracle

Multi-process multi-threaded Oracle uses multiple processes and multiple threads within each process to provide a new execution model for Oracle Database. Support for multi-process multi-threaded Oracle provides improved performance and manageability through more efficient sharing of system and processor resources.

Advanced Network Compression

New parameters, SQLNET_COMPRESSION and SQLNET.COMPRESSION_SCHEME_LIST, allow the compression of data transitioning over Oracle Net Services between client and server. Compression can be enabled at the: Connection level (connect string, URL),Service level (tnsnames.ora, ldap.ora) and Database level (sqlnet.ora)

Multiple Indexes 

Create multiple indexes on the same set of columns. In 11.2 and below, if we try to create an index using the same columns, in the same order, as an existing index, we get an error. In some cases, we may require  two different types of index on the same data (in a data warehouse where you might want a bitmap index on the leading edge of a set of columns that exists in a btree index).

Adaptive Execution Plans

12c support change of execution plan at run time


Auditing Enabled By Default

The new unified auditing architecture can be used in Oracle Database with no changes required to the database initialization parameters. This feature enables audit policies to be created and enabled in the database with no production database downtime, providing flexibility and ease of administration for database auditing.


Oracle Flex ASM

Oracle Flex ASM decouples the Oracle ASM instance from the database servers. Oracle Flex ASM instances may be run on separate physical servers from Oracle Database 12c instances.


Oracle Flex Cluster is a new Oracle Clusterware based topology utilizing two types of cluster nodes: Hub Nodes and Leaf Nodes. Hub Nodes represent traditional nodes,tightly coupled using network and storage. Leaf Nodes are a new type of node that runs a lighter weight stack and does not require direct shared storage connectivity.
Combining tightly coupled Hub Nodes and lightweight Leaf Nodes in one cluster allows the running of a variety of workload and applications across hundreds of nodes without additional overhead, while maintaining the ability to create dependencies between them. Centralized, cluster-wide management and standardized resource allocation policies further facilitate workload consolidation on Oracle Flex Cluster.

Oracle Cluster Registry Backup in ASM Disk Group Support

The Oracle Cluster Registry (OCR) backup mechanism enables storing the OCR backup in an Oracle ASM disk group.

Support for IPv6 Based IP Addresses for Oracle RAC Client Connectivity

Cluster nodes can be configured to use either IPv4 or IPv6 based IP addresses for the Virtual IPs (VIP) on the public network, while more than one public network can be defined for the cluster.

These are the few features of Oracle 12c for DBA. Expecting your comments...


  1. Thanks arun.. good article...

  2. Nice article...Concepts explained in simple words :)

  3. Good article...

  4. Well explained, in simple words....

  5. This is blog post is nice. explained well and specific. I cant wait to share this to my friends.

  6. Thank for sharing this useful information;
    It is very helpful to who are wanted to learn or update their knowledge on oracle 12c DBA through Oracle 12c DBA online training or offline training.