1. 4 Copyright © 2006, Oracle. All rights reserved. Recovering from Noncritical Losses

2. 4-2 Copyright © 2006, Oracle. All rights reserved. Objectives After completing this lesson, you should be able to: Recover temporary tablespaces Recover a redo log group member Recover from a lost index Re-create the password file

3. 4-3 Copyright © 2006, Oracle. All rights reserved. Causes of File Loss File loss can be caused by: User error Application error Media failure

4. 4-4 Copyright © 2006, Oracle. All rights reserved. You fix the problem by taking one of these actions: Create a new file. Rebuild the file. Recover the lost or damaged file. Critical Versus Noncritical A noncritical file loss is one where the database can continue to function.

5. 4-5 Copyright © 2006, Oracle. All rights reserved. Losing a TEMPFILE SQL> select * from big_table order by 1,2,3,4,5,6,7,8,9,10,11,12,13; select * from big_table order by 1,2,3,4,5,6,7,8,9,10,11,12,13 * ERROR at line 1: ORA-01565: error in identifying file '/u01/app/oracle/oradata/orcl/temp01.dbf' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory SQL statements that require TEMP space to execute fail if one of the tempfiles is missing.

6. 4-6 Copyright © 2006, Oracle. All rights reserved. Recovering from a TEMPFILE Loss Password file Parameter file SYSTEM SYSAUX UNDO USERS INDEX Redo log file 1B Redo log file 1A Redo log file 2B Redo log file 2A Control files TEMP

7. 4-7 Copyright © 2006, Oracle. All rights reserved. Log Group Status: Review A redo log group has a status of one of the following values at any given time: CURRENT : The LGWR process is currently writing redo data to it. ACTIVE : It is no longer being written to, but it is still required for instance recovery. INACTIVE : It is no longer being written to, and it is no longer required for instance recovery.

8. 4-8 Copyright © 2006, Oracle. All rights reserved. Errors in file /u01/app/oracle/admin/orcl/bdump/orcl_arc1_25739.trc: ORA-00313: open failed for members of log group 2 of thread 1 ORA-00312: online log 2 thread 1: '/u01/app/oracle/oradata/orcl/redo02b.log' ORA-27037: unable to obtain file status Linux Error: 2: No such file or directory Losing a Redo Log Group Member The alert log and the archiver process (ARCn) trace file record an error when a redo member file is missing.

9. 4-9 Copyright © 2006, Oracle. All rights reserved. Re-creating Redo Log Files SQL> ALTER DATABASE DROP LOGFILE MEMBER > '/u01/app/oracle/oradata/orcl/redo02b.log'; SQL> !rm /u01/app/oracle/oradata/orcl/redo02b.log SQL> ALTER DATABASE ADD LOGFILE MEMBER > '/u01/app/oracle/oradata/orcl/redo02b.log' > TO GROUP 2; Password file Parameter file SYSTEM SYSAUX UNDO USERS INDEX Redo log file 1A Redo log file 2A Control files TEMP Redo log file 1B Redo log file 2B

10. 4-10 Copyright © 2006, Oracle. All rights reserved. Recreating Redo Log Files (notes only slide)

11. 4-11 Copyright © 2006, Oracle. All rights reserved. Recreating Redo Log Files (notes only slide)

12. 4-12 Copyright © 2006, Oracle. All rights reserved. Re-creating Redo Log Files

13. 4-13 Copyright © 2006, Oracle. All rights reserved. Re-creating Indexes Use options to reduce the time it takes to create the index: PARALLEL NOLOGGING SQL> CREATE INDEX rname_idx 2 ON hr.regions (region_name) 3 PARALLEL 4;

14. 4-14 Copyright © 2006, Oracle. All rights reserved. Recreating Indexes (notes only slide)

15. 4-15 Copyright © 2006, Oracle. All rights reserved. Remote database administration Local database administration Yes No Do you have a secure connection? Use OS authentication. Use a password file. Authentication Methods for Database Administrators Do you want to use OS authentication?

16. 4-16 Copyright © 2006, Oracle. All rights reserved. Re-creating a Password Authentication File 1.Log in to the database by using OS authentication. 2.Set the REMOTE_LOGIN_PASSWORDFILE parameter to NONE and restart the database. 3.Re-create the password file by using orapwd. 4.Set REMOTE_LOGIN_PASSWORDFILE to EXCLUSIVE. 5.Add users to the password file and assign appropriate privileges to each user. 6.Restart the instance. $ orapwd file=$ORACLE_HOME/dbs/orapwORCL password=admin entries=5

17. 4-17 Copyright © 2006, Oracle. All rights reserved.

18. 4-18 Copyright © 2006, Oracle. All rights reserved. Summary In this lesson, you should have learned how to: Recover temporary tablespaces Recover a redo log group member Recover from a lost index Re-create the password file

19. 4-19 Copyright © 2006, Oracle. All rights reserved. Practice Overview: Recovering from Lost TEMPFILE and Redo Log File This practice covers the following topics: Starting the database with a missing tempfile Creating a new temporary tablespace Altering the default temporary tablespace for a database Recovering from a lost online redo log member

20. 4-20 Copyright © 2006, Oracle. All rights reserved.