Oracle database 12c new features

Oracle Database 12c
New Features
Prepared by

www.dbametrix.com
A world class Leader in Remote DBA Services

What are new features of Oracle 12
database?
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SQL Enhancement
Backup and Recovery
Database Management Enhancement
Oracle Networking Enhancement
Oracle Performance Tuning
Oracle ASM new Features
Oracle RAC new features

SQL Enhancement – New Features
• Now you can use TRUNCATE table CASCADE for
truncating primary and dependent table data as following
command.
• SQL> TRUNCATE TABLE <table_name> CASCADE;
• You can use above command in table partition too.
Above command will be truncating table data including
child records too.

• Output Rows restricting using FETCH FIRST N ROWS
ONLY in SQL statement.
• SELECT empno,ename,sal FROM emp ORDER BY
deptno DESC FETCH FIRST 5 ROWS ONLY;
• You can use 10 percent or 20 percent ROWS only
parameter in same SQL with limitation of N percent.

• You can create INVISIBLE column in table or modify
column to make INVISIBLE. Invisible column never
shows in general select * queries but it shows in result
where mention column in select query.

• SQL> CREATE TABLE test (testno number, t_name
varchar2(30), t_dept number(2) INVISIBLE);
• After creating above TEST table, you cannot see t_dept
column in select * query but able to see result in select
t_dept from test query.

• Invisible column can show via COLINVISIBLE SQL*Plus
command as following.
• SQL> SET COLINVISIBLE ON

• You can create session level SEQUENCE for testing. Which
will be deleted automatically after session log off.
• SQL> CREATE SEQUENCE test_seq START WITH 10
INCREMENT BY 10 SESSION;

• You can also modify SEQUENCE to make it session level
using ALTER command.
• SQL> ALTER SEQUENCE test_seq SESSION;
• For removing session parameter of sequence you should
need to execute ALTER SEQUENCE test_seq GLOBAL;

• You can extend datatype of VARCHAR2,RAW, and
NVARCHAR2 from 4000 bytes to 32,767 bytes.
• For using this feature, you should need to change
initialization parameter
MAX_STRING_SIZE=EXTENDED and restart database
in upgrade mode. After that you need to execute
• SQL> @?/rdbms/admin/utl32k.sql

• From Oracle database 12c, you can create multiple
indexes on column.
• This feature is available for composite columns and
single index both.

Backup and Recovery – New
Features
• New Backup privilege introduced called SYSBACKUP.
• It means now there is no need to give SYSDBA privilege
for performing backup and recovery tasks.

• Sample command is following.
• $ ./rman target “rman/rman as SYSBACKUP"

Features
• Real time Apply redo log to Data Guard.
• In previous release of Oracle 12c, default option was
apply redo from archived log files on the standby
database.
• In Oracle Database 12c Release, the default
configuration is to use real-time apply so that redo is
applied directly from the standby redo log file.
• This new feature helps to maintain minimum or zero data
loss.

Features
• Active DATA GUARD is now accepting DML operations
on Global temporary tables.
• Active standby database can be open in read only mode.
• Active standby database is now supported DML
operations on Global Temporary Tables.
• This feature enhances reporting facility and performance
of primary database.

Features
• Direct SQL statement execution in RMAN utility. Now no
need of any prefix like “sql” in RMAN command line.

• RMAN> SELECT sid,serial#,status FROM v$session;

Features
• Table level recovery is now possible using RMAN. In
prior versions this feature didn‟t available.
• RECOVER TABLE username.tablename UNTIL TIME
„<TIMESTAMP>…' AUXILIARY DESTINATION
'/u01/backup' DATAPUMP DESTINATION '/u05/dumpdir'
DUMP FILE 'tablename.dmp' NOTABLEIMPORT
• REMAP TABLE „<username.tablename>':
„<username.new_table_name>';

Features
• In Datapump, new parameter introduced called
TRANSFORM with DISABLE_ARCHIVE_LOGGING.
This option will disable archive log generation during
import process.

• impdp directory=dpump dumpfile=test.dmp
logfile=test.log
TRANSFORM=DISABLE_ARCHIVE_LOGGING:Y

Database Management– New
Features
• Now you can move active data file online without
copying to another destination as following command.
• ALTER DATABASE MOVE DATAFILE
'/u01/data/test_tbs01.dbf' TO '/u02/data/test_tbs01.dbf';
• You can monitor above ongoing process using dynamic
data dictionary view V$SESSION_LONGOPS

Features
• New Feature called PLUGGABLE database and
CONTAINER database introduced in Oracle 12c.
• Container database contains pluggable database. You
can say database in database. Pluggable database
plugs in to container database.
• This feature helps to better database administration and
management tasks. It shorten memory usage and disk
usage.
• You can plug in pluggable database into any container
database. Single container database contains many
pluggable database.

Features
• Now you can enable logging mode of every Data
Definition Language (DDL). Every DDL command will be
logged in trace file at operating system disk.
• For enabling this feature, you should need to enable
parameter ENABLE_DDL_LOGGING=TRUE.
• Trace files would be generating in following directory
• $ORACLE_BASE/diag/rdbms/DBNAME/log/ddl

Features
• You can merge/split/add table partitions in single SQL
command.
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ALTER TABLE test_p
ADD PARTITION
PARTITION part11 VALUES LESS THAN (120000),
PARTITION part12 VALUES LESS THAN (130000);

Features
• You can move table partition online or offline using
following command.
• Offline command=>
• ALTER TABLE table_name MOVE
PARTITION|SUBPARTITION <partition_name> TO
tablespace <tablespace_name>;
• Online command=>
• ALTER TABLE table_name MOVE
PARTITION|SUBPARTITION <partition_name> TO
tablespace <tablespace_name> UPDATE INDEXES
ONLINE;

Features
• You can truncate/drop multiple partitions in single DDL
command as following.
• ALTER TABLE test_p DROP PARTITIONS part7,part9
UPDATE GLOBAL INDEXES;
• ALTER TABLE test_p TRUNCATE PARTITIONS
part7,part9 UPDATE GLOBAL INDEXES;

Features
• Preupgrade script is now available in Oracle 12c
database for investigating preupgrade issues to fix.
• Preupgrade script called preupgrd.sql is available in
rdbms/admin folder.
• Preupgrade_fixup.sql log file will be generated in
$ORACLE_BASE/cfgtoollogs directory.
• This script helps to investigation of certain issues of
upgrade process and we can easily resolve issue using
preupgrade_fixup.sql. This feature can save our time of
database upgrade activity.

Oracle Networking Enhancement –
New Features
• In Oracle 12c database, you can restore and recover
data file over through net. Means you can
restore/recover data file from standby database to
primary database vice versa using service option with
following command in RMAN.

• RMAN> RECOVER DATABASE FROM SERVICE
prod_service USING COMPRESSED BACKUPSET;

Oracle Performance Tuning – New
Features
• You can gather object or database statistics
concurrently. This feature generates statistics multiple
tables/indexes simultaneously.
• For using this feature, you should have nonzero value in
parameter JOB_QUEUE_PROCESSES and you need to
set following parameters.
• EXEC
DBMS_STATS.SET_GLOBAL_PREFS('CONCURRENT'
, 'ALL');

Features
• Excellent feature of Temporary Undo.
• In Oracle 12c, now temporary undo would be generated
in temporary tablespace. This feature eliminates
unnecessary redo generation of temp tablespace usage.

• For enabling temporary undo, you need to make sure to
set initialization parameter
TEMP_UNDO_ENABLED=true.

Features
• Program Global Area (PGA) Limitation.
• You can restrict PGA allocation in to database. In prior
version this feature wasn‟t available.
• You can use parameter
PGA_AGGREGATE_LIMIT=<some value> to enable this
limitation of PGA.
• Once you define this value then Oracle won‟t expand
more than this size of PGA. This feature helps to avoid
paging/swapping and memory bottleneck issues.

Features
• Real Time Automatic Database Diagnostic Monitor
ADDM.
• This feature available with Oracle EM control of 12c only.
• In OEM portal, you can select real time ADDM in
performance option for investigating findings of
production database.
• This feature is absolutely new and present there is no
another command line option available. Means you need
OEM control for using this option.

Oracle ASM – New Features
• ASM Disk Rebalance Estimation
• Like EXPLAIN PLAN FOR, new command introduced as
EXPLAIN WORK FOR. Using this statement, Oracle
gathers and shows ASM disk rebalance estimation in
V$ASM_ESTIMATE view.
• Example:
• EXPLAIN WORK FOR ALTER DISKGROUP DS_DATA1
ADD DISK dsd_03;
• After successfully execution of above command you can
check estimation cost in V$ASM_ESTIMATE for setting
proper value of POWER limit for faster task.

• New feature introduced called FLEX ASM.
• When any instance terminated in ASM, then any survival
ASM instance will be up within flex cluster to maintain
high availability.
• For enabling this feature, we need to install flex cluster
using Oracle clusterware and this option automatically
install flex ASM option at node.
• You can enable flex ASM using ASMCA utility in your
cluster environment.

• For checking and repairing logical corruption of disks,
new facility introduced called ASM DISK Scrubbing.
• Using this facility, now you can check and repair disk for
getting rid of logical corruption.
• Example:
• ALTER DISKGROUP DS_DATA1 SCRUB POWER
LOW:HIGH:AUTO:MAX;
• ALTER DISKGROUP DS_DATA1 SCRUB FILE
'+DG_DATA/TEST/DATAFILE/test.xxxx.xxxx' REPAIR
POWER AUTO;

Oracle RAC – New Features
• Now Flex Cluster supported in Oracle 12c.
• Flex cluster architecture contains hub and leaf nodes.
• Hub nodes are regular RAC nodes which are having
DIRECT access of storage and directly read/write.
• Leaf nodes are not having DIRECT access of storage
and they will get access through HUB node.
• It means you can have HUB nodes without leaf nodes
but You cannot have leaf nodes without hub nodes.
• You can convert any node as leaf node as following.
• $ ./crsctl get node role config
• $ ./crsctl set node role hub|leaf

Oracle RAC – New Features
• Now you can start instance or database as NO MOUNT,
MOUNT, and OPEN stage using SRVCTL command.
• This facility doesn‟t available in prior of Oracle 12c.
• Example command is following….
• srvctl start|stop database|instance –startoption
NOMOUNT|MOUNT|OPEN

Oracle 12 Database New
Features
Prepared By

http://www.dbametrix.com
A world class Leader in Remote DBA Services

Oracle database 12c new features

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