Oracle 12c Database : New Features : C for Cloud

Oracle 12c Database : New Features : C for Cloud

At Oracle Open World there was a number of presentation on the new features that we will see in the new release of the database, which is being called 12c, where c is for the cloud.

Here are some of the features will be available : (

§  Pluggable Database : In a pluggable database environment, you create a single database container, and plug multiple databases into this container. They key design feature here is that, all these databases then share the exact same oracle server processes (aka background processes) and memory (Unlike in the previous versions where each database got its own set of background processes and shared memory allocation).In oracle versions upto 11gr2, when you used database resource management, you had to setup resource plans per database, and each of the database did not know about the resource utilization of other databases on the same server. So you have to use Instance Caging in order to ensure that database’s used only their allocated amount of cpu resources. In Oracle 12c, since all the databases use the same container, the container will know about the resource utilization of all the databases and hence can do the database resource management efficiently.

§  The 12c database will be a multi-tenant database. What does this mean? If means that we can have multiple databases running on the same server sharing the same memory and process management. Under the current configuration, when we create a new database on a server we create a separate set of processes and memory allocation.  Oracle is calling this, Pluggable Databases

§  MapReduce in the Database – MapReduce can be run from PL/SQL directly in the database.

§  Improved default value management. We will be able to clearly how to allocate a value to or calculate a value as a default for a column. The first of these is that we will be able to assign a sequence to a column. Example x int default s.nextval primary key. We can then insert into a table and not worry about how to calculate a primary key value,insert into t(y) values (‘hello world’);.  We will also be able to specify a default value when no value is being inserted into a column, z number default on null 42

§  Increased size for VARCHAR2, NVARCHAR2 and RAW data types up to 32K in size. You will need to se the Max_SQL_String_Size in the init.ora to EXTENDED. But this new size limit is not supported in clustered and index organised tables.

§  Some improvements to PARTITIONing, with asynchronous global index maintenance for DROP and TRUNCATE partition. New CASCADE functionality for TRUNCATE and EXCHANGE partition. You will be able to perform multiple partition operations with a single DDL command.

§  There will be better Statistics for query performance including Hybrid Historgrams, Session Private Statistics and statistics will be gathered during data loads automatically.

§  Temporary UNDO for objects will be handled in TEMP

§  APEX 4.2 is out now and has lots of new features in particular features for creating mobile applications including transitions, gestures, changes in orientation and HTML 5 support. Coming in 12c APEX will be able to support the pluggable database environment. You will have the option to install APEX in the Contain database or in the pluggable databases. It will also support the extended VARCHAR2 size

§  SQL Developer will have Data Pump to allow for fast movement of data and for scheduling of the movements. The Database Difference tool has been redesigned to give more options and gives a more reliable comparison. A redesigned Database Copy (more options), improved Migrations and PDF report generation. SQL Developer is not the admin tool to manage the APEX Listener. UI improvements include more/better drag and drop, GRANT statement support in SQL editor and database Doc reporting. A new release of SQL Developer will be made available with the release of 12c that includes all the 12c new features

§  Better Data Compression of data being sent to/from the client/server. So how you use the ORDER BY clause will become more important

§  We will now have BOOLEAN in 12c but only in PL/SQL 

§  12c will allow you to grant ROLES to PL/SQL program units. Or we could specify a White List that lists what other code units can call your code. This is a great security enhancement, although it involves more admin work, but it is worth it.

§  12c will allow you to include PL/SQL in WITH

§  12c will allow you to create duplicate indexes on the same set of columns. Sometimes you might want two different types of index on the same data, for example a bit map index and a b-tree index.

§  Cursor results sets can now be returned implicitly instead of the existing explicit method

§  The Warning messages when compiling our PL/SQL code can be filtered based on if they are Severe, Performance related or just Informational. This can be set at a System or Session level.

§  alter session set plsql_warnings=’enable:severe’;

alter session set plsql_warnings=’enable:performance’;

alter session set plsql_warnings=’enable:informational’;