Oracle database 12c new features


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New Features for Database Administrator of Oracle 12c Database. Here are some of excellent Oracle 12c new features with examples for learning purpose. SQL,Backup and recovery, Database management, Oracle RAC, Oracle ASM included.

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Oracle database 12c new features

  1. 1. Oracle Database 12c New Features Prepared by A world class Leader in Remote DBA Services
  2. 2. What are new features of Oracle 12 database? • • • • • • • SQL Enhancement Backup and Recovery Database Management Enhancement Oracle Networking Enhancement Oracle Performance Tuning Oracle ASM new Features Oracle RAC new features
  3. 3. 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.
  4. 4. SQL Enhancement – New Features • 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.
  5. 5. SQL Enhancement – New Features • 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.
  6. 6. SQL Enhancement – New Features • Invisible column can show via COLINVISIBLE SQL*Plus command as following. • SQL> SET COLINVISIBLE ON
  7. 7. SQL Enhancement – New Features • 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;
  8. 8. SQL Enhancement – New Features • 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
  9. 9. SQL Enhancement – New Features • From Oracle database 12c, you can create multiple indexes on column. • This feature is available for composite columns and single index both.
  10. 10. 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"
  11. 11. Backup and Recovery – New 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.
  12. 12. Backup and Recovery – New 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.
  13. 13. Backup and Recovery – New 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$session;
  14. 14. Backup and Recovery – New Features • Table level recovery is now possible using RMAN. In prior versions this feature didn‟t available. • RECOVER TABLE username.tablename UNTIL TIME „<TIMESTAMP>…' AUXILIARY DESTINATION '/u01/backup' DATAPUMP DESTINATION '/u05/dumpdir' DUMP FILE 'tablename.dmp' NOTABLEIMPORT • REMAP TABLE „<username.tablename>': „<username.new_table_name>';
  15. 15. Backup and Recovery – New Features • In Datapump, new parameter introduced called TRANSFORM with DISABLE_ARCHIVE_LOGGING. This option will disable archive log generation during import process. • impdp directory=dpump dumpfile=test.dmp logfile=test.log TRANSFORM=DISABLE_ARCHIVE_LOGGING:Y
  16. 16. Database Management– New Features • Now you can move active data file online without copying to another destination as following command. • ALTER DATABASE MOVE DATAFILE '/u01/data/test_tbs01.dbf' TO '/u02/data/test_tbs01.dbf'; • You can monitor above ongoing process using dynamic data dictionary view V$SESSION_LONGOPS
  17. 17. Database Management– New 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.
  18. 18. Database Management– New 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
  19. 19. Database Management– New Features • You can merge/split/add table partitions in single SQL command. • • • • ALTER TABLE test_p ADD PARTITION PARTITION part11 VALUES LESS THAN (120000), PARTITION part12 VALUES LESS THAN (130000);
  20. 20. Database Management– New 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;
  21. 21. Database Management– New 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;
  22. 22. Database Management– New 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.
  23. 23. 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;
  24. 24. 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');
  25. 25. Oracle Performance Tuning – New 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.
  26. 26. Oracle Performance Tuning – New 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.
  27. 27. Oracle Performance Tuning – New 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.
  28. 28. 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.
  29. 29. Oracle ASM – New Features • 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.
  30. 30. Oracle ASM – New Features • 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;
  31. 31. 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
  32. 32. 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
  33. 33. Oracle 12 Database New Features Prepared By A world class Leader in Remote DBA Services