In previous release 11G to manage database you could use Oracle Enterprise Database Console. In Oracle 12C it is replaced by new lightweight administration tool Enterprise Manager Database Express.

Features of the new version:

• out-of-box simple management for single database (or database cluster)
• small footprint 50-100 MB in database
• minimal requirements for CPU in database(sql calls), rendering is done on client side
• simple configuration
• includes
  • performance monitoring
  • configuration management
  • administration
  • diagnostic and tuning
• interface in web browser(requires flash plugin)

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This article presents installation of Oracle Database 12C(12.1) on Centos 6. Both database and grid software(standalone version) are installed. Grid software will use devices configured using three methods:

• disk devices configured using UDEV
• disk devices accessed by NFS
• kmod-oracleasm library – extra Red Hat 6 rpm to simulate oracleasm lib

In this article there are two separated users:

• oracle – manage database software and databases
• grid – manage grid software and asm database.

Read following article how to install Centos 6 Linux: Install Centos 6 64 bit(for comfort set 4G memory and 64G for disk in your virtual machine).

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New clause ACCESSIBLE BY  in Oracle 12C enables to extend standard security. It defines list of database objects (later called accessors) that can call your PL/SQL code.

Clause ACCESSIBLE BY can be defined for following statements:

• CREATE FUNCTION
• CREATE PACKAGE
• CREATE PROCEDURE
• CREATE TYPE

List of accessors that can call your code includes database objects like:

• TRIGGER
• FUNCTION
• PROCEDURE
• PACKAGE
• TYPE

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This new feature in Oracle 12C is as default always on. Each TRUNCATE or DROP commands performed on a partition automatically triggers asynchronous global index maintenance. It means that you don’t need to wait for global INDEX maintenance :).

For backward compatibility you still need to specify UPDATE INDEXES clause.

Limitations of asynchronous global index maintenance:

• Only performed on heap tables
• No support for tables with object types
• No support for tables with domain indexes
• Not performed for the user SYS

Asynchronous cleanup orphans in an index can be done:

• Automatically
  • by Oracle job SYS.PMO_DEFERRED_GIDX_MAINT_JOB
• Manually
  • just run above job SYS.PMO_DEFERRED_GIDX_MAINT_JOB
  • run procedure DBMS_PART.CLEANUP_GIDX
  • run sql statement ALTER INDEX REBUILD [PARTITION] – the same like in previous releases
  • run sql statement ALTER INDEX [PARTITION] COALESCE CLEANUP

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In Oracle 12C new parameter for Oracle Data Pump can be specified LOGTIME. It defines if Data Pump messages are timestamped so you can quickly figure out elapsed time between different phases of a Data Pump. Very useful to analyze performance problems and general timings for Data Pump processes.

Syntax

LOGTIME=[NONE | STATUS | LOGFILE | ALL]

Description:

• NONE      – No timestamps on status or log file messages (same as default)
• STATUS   – Timestamps on status messages only
• LOGFILE – Timestamps on log file messages only
• ALL          – Timestamps on both status and log file messages

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In release 12C Oracle automatically gathers statistics for following operations:

• CREATE TABLE AS SELECT
• INSERT /*+ APPEND */ INTO … SELECT on en empty table using direct path

It’s very similar behavior to statistics gathering done during a CREATE INDEX or INDEX REBUILD. No init.ora or any manual settings are required to turn on this feature. Now you can save a lot of time by skipping extra step to collect statistics Continue reading →