presentation day1oracle 12c

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Oracle 12c Multitenant Architecture

Introduction of CDB and PDB Databases

(Reference – Oracle documentation)

Check detailed contents on http://dbaboss.com/

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What is Multitenant

• Multi-tenancy is an design in which a single instance of a software application serves multiple customers. Each client is called a tenant.

• With a multitenant architecture, a software application is designed to provide all tenant a committed share of the instance including its data, configuration, user management, tenant individual functionality and non-functional possessions.


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• It has been an organizational outlandish when multiple databases are running in one machine. The backups need to be run independently. Each database has memory footmark and each database has background processes. This increases the capacity of the server on what it can lever in terms of the loads. By joining into one container database and at the same time keeping all of them as separate databases are a great thing from association, performance, capacity and operational perspective. This is going to help in a very big way for consolidation on many enterprises and at the same time it will reduce the server footprint significantly giving the maximum Return on Investments (ROI) on the middleware database technologies.


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Oracle 12c Multitenant Architecture Overview

• A new selection for Oracle Database 12c, Oracle Multitenant supplies a new architecture that allows a multitenant container database to hold many pluggable databases. At present database can simply be accepted with no application changes required. Oracle Multitenant fully complements other options, including Oracle Real Application Clusters and Oracle Active Data Guard.


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• The multitenant architecture empowers an Oracle database to function as a multitenant container database (CDB) that includes zero, one, or many customer-created pluggable databases (PDBs).

• A PDB is a transportable collection of schemas, schema objects, and nonschema objects that appears to an Oracle Net client as a non-CDB. All Oracle databases before Oracle Database 12c were non-CDBs.


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What is CDB, PDB and Seed Database

• Container Database (CDB): The primary database that comprises numerous plugged-in databases. Numerous operations can be performed at the container level to reduce management costs. A database is generated as either a CDB or a non-CDB. On the apparent this seems very similar to a conventional Oracle database, as it contains most of the working parts you will be already familiar with (control files, data files, undo, tempfiles, redo logs etc.). It also lines the data dictionary for those objects that are owned by the root container and those that are visible to all PDBs.A container is a pool of schemas, objects, and related structures in a multitenant container database (CDB) that appears logically to an application as a separate database. Within a CDB, each container has a unique ID and name.It also called root container.


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• Pluggable Database (PDB): A set of schemas, objects, and non-schema objects that can be plugged and unplugged from a container database. The PDB appears to Oracle Net and end users as a Non cdb database in and of itself but is actually managed within a container that may have many PDBs. Since the CDB comprises most of the working parts for the database, the PDB only needs to contain information precise to itself. It does not need to worry about controlfiles, redo logs and undo etc. As an alternative it is just made up of datafiles and tempfiles to handle it's own objects. This contains it's own data dictionary, containing information about only those objects that are specific to the PDBSeed Database.PDBs isolate data and operations so that from the standpoint of a user or application, each PDB appears as if it were a traditional non-CDB.


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• The maximum limit to the total number of Pluggable databases within a container database is close to 250. So you can have up to 250 pluggable databases or PDBs within one container database or CDB. It is clear that there is one-to-many relationship between CDB and PDBS.

• (Seed PDB):

A default PDB that the system uses as a template to quickly facilitate other user-created PDBs. Within, it’s called PDB$SEED

• Below picture refer in Oracle docs


9Check detailed contents on

http://dbaboss.com/


http://dbaboss.com/

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• The new multitenancy choice in Oracle Database 12c that permits you to create several virtual databases (PDB) called pluggable databases or containers in a single physical database called container database (CDB). The CDB is the one that has the Oracle instance connected with it, i.e. it has the background processes such as pmon, smon and the memory areas such as buffer cache and large pool. The PDBs do not have their own instance; but take up house inside the CDB, with some extra storage private to them. This preparation permits you to address the PDBs as independent databases. So you can create a user called, say, DBABOSS in every PDB, as an alternative of creating a new database for creating these users. This is highly useful in case of applications that require a specifically named schema, e.g. PeopleSoft have need of a user so-called SYSADM. If you want to place numerous PeopleSoft applications inside one database, you can't, since you can't create more than one user with the name SYSADM. So you had to resort to producing several databases to hold several copies of the application. Each of these databases had its own memory and resource overheads. In a multitenancy model you can create several PDBs instead of actual databases. Each PDB can then have a user named SYSADM and run its copy of the PeopleSoft application but without consuming any extra memory and CPU.


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• While these PDBs are accommodated in a single CDB, they have the many of the individualities of a regular independent database. For instance you can set a specific optimizer limitation to different values in different PDBs. You can, of course, start and shutdown a PDB leaving other PDBs in the CDB unaffected. You can back up PDBs independently, as RMAN knows which specific files are relevant for the PDBs. You can restore individual PDBs, even perform a point in time recovery for a PDB while the others are running.

• This allows you to create a accurate "cloud database" where you can host as numerous databases as you want without increasing the memory and CPU footmark. This is principally useful when you have financial limitations that prevent creation of supplementary databases forcing difficulties in development cycles. You can spin up a PDB very quickly to host the development effort, or even clone it from another PDB from either the same CDB or a different one, even a different server. This ability of creating virtual databases unfastens the database provisioning from hardware provisioning. All the PDBs share the same resources. If the overall request becomes too high, all you have to do add the resources to the CDB and all the PDBs get the benefit immediately. Perhaps the biggest advantage is seen during upgrades. Instead of upgrading multiple databases, all you have to do is to upgrade the CDB and all PDBs in it are directly upgraded


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Benefits • Achieve many databases as one.• Come across service-level prospects with

built-in workload resource management.• Keep the isolation of separate databases

without shifting applications or access rights.• Increase scalability and server consumption.• Oracle multitenant databases were developed

to help companies take advantage of virtualization.


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• High association compactness.

The many pluggable databases in a single container database share its memory and background processes, permitting you operate many more pluggable databases on a precise platform than you can single databases that use the old architecture. This is the equal profit that schema-based association brings. But there are noteworthy barriers to adopting schema-based consolidation, and it causes ongoing operating problems. The new architecture removes these adoption barriers and operating problems.


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• Speedy provisioning and cloning using SQL.. A pluggable database can be unplugged from one container database and plugged into another. Instead, you can clone one, within the same container database, or from one container database to another. These operations, together with creating a pluggable database, are done with new SQL commands and take just seconds. When the fundamental file system supports thin provisioning, many terabytes can be cloned almost instantaneously simply by using the keyword snapshot in the SQL command


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• New standards for rapid patching and upgrades. The deal of time and effort to patch one container database results in patching all of its many pluggable databases. To patch a single pluggable database, you simply unplug/plug to a container database at a different Oracle Database software version.• Accomplish many databases as one. By combining existing databases as pluggable databases, administrators can manage many databases as one. For example, tasks like backup and disaster recovery are performed at the container database level.• Vibrant between-pluggable database resource management. Oracle Database 12c Resource Manager is extended with specific functionality to instantly control the competition between the pluggable databases within a container database


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What is extra • Unplug and Plug PDBWhat is additional? We can plug out (unplug) a database from one container database and then plug in into another container database. This is attractive cool feature. This could be useful in many situations. Migrating databases to new platform. Migrating databases to new hardware. Migrating databases to new DB releases. Moving databases to different systems. Enhancing high availability of databases by moving between systems


presentation day1oracle 12c

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