In this article we will
12c features related to Multitenant Database
12c database Support
both non-CDB and CDB architecture and Multitenant architecture can work on
Oracle RAC as well as on Active Data Guard.
Understanding Why Multitenant database?
Below are few reason to
know reason behind using Multitenant database
Cost reduction
Reduce capital expenses
Reduce hardware footprints
Reduce operating cost (license, maintenance, monitor)
Easy provisioning
Easier
and rapid movement of data and code and separation of code
Easy
to plug and unplug database across same and different servers
Database consolidation
Easy to manage
Easy
migration and testing
Easy
to monitor, maintain and backed up
Quicker environment
refresh activities
Less
administration work related to database Patching and better security control
than normal pre-12 databases
Ease of performance tuning
DR configuration
Ease of performance tuning
DR configuration
Next point comes in mind that What is pluggable
database?
Definition: Simple
meaning is Many database in single database - Multiple Pluggable databases
(PDBs) in single Container Database (CDB) acts like separate database even
though they shares the physical as well as logical structures.
Terminologies to
Remember
Root Container - Like a meta database (CDB$ROOT) which
stores the system metadata required to manage PDBs.
Container – This is Logical structure which is
collection of schemas, object and related structures in CDB that appears as a
separate database to application
Container database(CDB )- SYS is common schema in CDB which owned
all PDBs. Every CDB has Control files, Redo log files, Undo tablespace,
Global temporary tablespace, SYSTEM & SYSAUX tablespace along with
any additional tablespace.
Pluggable database (PDB)- which is user created set of schemas and objects. PDB
isolated data and operation and must be uniquely named within a
CDB. PDBs shares control files, redo logs, undo and
global temporary tablespace from CDB whereas PDBs have their own SYSTEM
tablespace, SYSAUX tablespace, Local temporary and individual Application
tablespaces. maximum 252 PDBs are allowed in single instance.
Common between CDB and PDB's
-Background processes
-Redo logs- these are common for entire database (Container)
-Memory
-Control files
-Global Temp tablespace
-undo tablespace
-network admin files like listener.ora, tnsnames.ora, sqlnet.ora etc.
-SGA
Individual for PDB's
-Separate SYSTEM and SYSAUX tablespace
-Individual tablespaces or datafiles
-Local temp tablespace
-Local users and local roles
-Local metadata of PDB's
-PDB resource manager
(Also read- User creation in 12c and clone remote PDB using database link )
Keep watching more is coming on Oracle 12c
Keep watching more is coming on Oracle 12c
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