6 Downgrading a Database

Supported Releases for Downgrading

You can downgrade both major releases and patchset releases, based on the original release from which the database was upgraded. Major release downgrades are supported back to Oracle Database 11g Release 1 (11.1.0.6), Oracle Database 10g Release 2 (10.2.0.2), and Oracle Database 10g Release 1 (10.1.0.5). Patchset downgrades are supported back to all prior 11.2 patch releases.

If you have Oracle Database Vault installed with your Oracle Database 11g Release 2 (11.2) database, then you can downgrade to release 11.1.0.6 and release 11.1.0.7 only.

If you have Messaging Gateway or Workspace Manager in your database, then be aware that neither of them are part of Oracle Database patchsets prior to release 10.2.0.4. Therefore, you must separately apply all relevant patches to the release 10.2.0.3 or release 10.1.0.5 Oracle home before downgrading.

Downgrade is not supported for Oracle Enterprise Manager. However, if you save your Oracle Enterprise Manager Database Control files and data before upgrading your database, then you can restore the old version of Database Control after downgrading the database.

Check for Incompatibilities

Check the compatibility level of your database to see if the database might have incompatibilities that prevent you from downgrading. If the compatibility level of your Oracle Database 11g Release 2 (11.2) database is 11.2.0 or higher, then you are not able to downgrade.

If you are downgrading to Oracle Database 11g Release 1 (11.1), then the COMPATIBLE initialization parameter must be set to 11.0.0 or lower.

If you are downgrading to Oracle Database 10g Release 2 (10.2), then the COMPATIBLE initialization parameter must be set to 10.2.0 or lower.

If you are downgrading to Oracle Database 10g Release 1 (10.1), then the COMPATIBLE initialization parameter must be set to 10.1.0.

Perform a Full Backup

Perform a full backup of your Oracle Database 11g Release 2 (11.2) database before you downgrade.

Downgrade the Database

Complete the following steps to downgrade your Oracle Database 11g Release 2 (11.2) database to a major release or a relevant patchset upgrade:

1. If you have enabled Oracle Database Vault on your database, then you must:

   • Grant the Database Vault DV_PATCH_ADMIN role for the SYS account.

   • Disable Database Vault before downgrading the database.

   See Also:

   Oracle Database Vault Administrator's Guide for instructions about disabling Oracle Database Vault

2. If you set the ORA_TZFILE environment variable to the full path name of the timezone.dat file when you upgraded to Oracle Database 11g Release 2 (11.2), then you must unset it if you subsequently downgrade your database.

   Two time zone files are included in the Oracle home directory:

   • The default time zone file at

     $ORACLE_HOME/oracore/zoneinfo/timezonelrg.dat
     

   • A smaller time zone file at

     $ORACLE_HOME/oracore/zoneinfo/timezone.dat
     

   If you do not unset the ORA_TZFILE variable, then connecting to the database using the smaller time zone file might produce the following errors:

   SP2-1503: Unable to initialize Oracle call interface
   SP2-0152: ORACLE may not be functioning properly
   

   See Also:

   Oracle Database Globalization Support Guide for more information about datetime data types and time zone support

3. If you have Oracle Application Express on your database, then you must copy the apxrelod.sql file from the Oracle Database 11g Release 2 (11.2) ORACLE_HOME/apex/ directory to a directory outside of the Oracle home, such as the temporary directory on your system.

   Make a note of the new location of this file.

4. Log in to the system as the owner of the Oracle Database 11g Release 2 (11.2) Oracle home directory.

5. This step is required only if Enterprise Manager Database Control is already configured for the database.

   Stop Database Control, as follows:

   1. Set the ORACLE_UNQNAME environment variable to the database unique name.

   2. Run the following command:

      ORACLE_HOME/bin/emctl stop dbconsole
      

   If the database being downgraded is an Oracle Real Application Clusters (Oracle RAC) database, then perform this step on all instances.

6. If you are downgrading an Oracle RAC database to 10g Release 1 (10.1), then you must remove extra voting disks before shutting down the Oracle Clusterware stack.

   1. To see the number of voting disks used and to list voting disk paths, run the following command:

      Oracle_Clusterware_Home/bin/crsctl query css votedisk
      

   2. Remove each additional voting disk you find in the previous step by running the following command, where path is a voting disk path discovered in the previous step:

      Oracle_Clusterware_Home/bin/crsctl delete css votedisk path
      

7. At a system prompt, change to the ORACLE_HOME/rdbms/admin directory.

   Note:

   If you are downgrading a cluster database, then shut down the instance completely and change the CLUSTER_DATABASE initialization parameter to false. After the downgrade, you must set this parameter back to true.

8. Start SQL*Plus.

9. Connect to the database instance as a user with SYSDBA privileges.

10. Start up the instance in DOWNGRADE mode:

    SQL> STARTUP DOWNGRADE
    

    You might be required to use the PFILE option to specify the location of your initialization parameter file.

11. If you have Enterprise Manager configured in your database, then drop the Enterprise Manager user:

    DROP USER sysman CASCADE;
    

    Note:

    After this step, MGMT* synonyms may be invalid. Follow the guidelines in "Restoring Oracle Enterprise Manager" to validate the synonyms.

12. Set the system to spool results to a log file for later verification of success:

    SQL> SPOOL downgrade.log
    

13. Run catdwgrd.sql:

    SQL> @catdwgrd.sql
    

    The following are notes about running the script:

    • You must use the version of the script included with Oracle Database 11g Release 2 (11.2).

    • You must run the script in the Oracle Database 11g Release 2 (11.2) environment.

    • The script downgrades all Oracle Database components in the database to the major release or Oracle Database 11g patch release from which you originally upgraded.

    If you encounter any problems when you run the script, or any of the scripts in the remaining steps, then correct the causes of the problems and rerun the script. You can rerun any of the scripts described in this chapter as many times as necessary.

    If the downgrade for a component fails, then an ORA-39709 error is displayed and the SQL*Plus session terminates without downgrading the Oracle Database data dictionary. All components must be successfully downgraded before the Oracle Database data dictionary is downgraded. You must identify and fix the problem before rerunning the catdwgrd.sql script.

14. Turn off the spooling of script results to the log file:

    SQL> SPOOL OFF
    

    Then, check the spool file and verify that there were no errors generated during the downgrade. You named the spool file in Step 12; the suggested name was downgrade.log. Correct any problems you find in this file and rerun the downgrade script if necessary.

15. Shut down the instance:

    SQL> SHUTDOWN IMMEDIATE
    

16. Exit SQL*Plus.

17. If your operating system is Linux or UNIX, then change the following environment variables to point to the directories of the release to which you are downgrading:

    • ORACLE_HOME

    • PATH

    You should also check that your oratab file and any client scripts that set the value of ORACLE_HOME point to the downgraded Oracle home.

    See Also:

    Your operating system-specific Oracle Database 11g Release 2 (11.2) installation documents for information about setting other important environment variables on your operating system

18. If your operating system is Windows, then complete the following steps:

    1. Stop all Oracle services, including the OracleServiceSID Oracle service of the Oracle Database 11g Release 2 (11.2) database, where SID is the instance name.

       For example, if your SID is ORCL, then enter the following at a command prompt:

       C:\> NET STOP OracleServiceORCL
       

       See Also:

       The Oracle Database Platform Guide for Microsoft Windows that is specific to your Microsoft Windows environment for information about stopping services

    2. Delete the Oracle service at a command prompt by issuing the ORADIM command. For example, if your SID is ORCL, then enter the following command:

       C:\> ORADIM -DELETE -SID ORCL
       

    3. Create the Oracle service of the database that you are downgrading at a command prompt using the ORADIM command.

       C:\> ORADIM -NEW -SID SID -INTPWD PASSWORD -MAXUSERS USERS
            -STARTMODE AUTO -PFILE ORACLE_HOME\DATABASE\INITSID.ORA
       

       This syntax includes the following variables:

       Variable	Description
       SID	Same SID name as the SID of the database being downgraded.
       PASSWORD	Password for the database instance. This is the password for the user connected with SYSDBA privileges. The -INTPWD option is not required. If you do not specify it, then operating system authentication is used, and no password is required.
       USERS	Maximum number of users who can be granted SYSDBA and SYSOPER privileges.
       ORACLE_HOME	Oracle home directory of the database to which you are downgrading. Ensure that you specify the full path name with the -PFILE option, including drive letter of the Oracle home directory.

       
       

       For example, if you are downgrading to Oracle Database 10g Release 2 (10.2), if your SID is ORCL, your PASSWORD is TWxy5791, the maximum number of USERS is 10, and the ORACLE_HOME directory is C:\ORANT, then enter the following command:

       C:\> ORADIM -NEW -SID ORCL -INTPWD TWxy5791 -MAXUSERS 10
            -STARTMODE AUTO -PFILE C:\ORANT\DATABASE\INITORCL.ORA
       

       Note:

       You are not required to change any Windows Registry settings when downgrading a database. The oradim utility makes all necessary changes automatically.

19. Restore the configuration files (for example, parameter files, password files, and so on) of the release to which you are downgrading.

    If this is an Oracle RAC database, execute the following command to return the database to single instance mode:

    SET CLUSTER_DATABASE=FALSE
    

    Note:

    If you are downgrading a cluster database, then perform this step on all nodes in which this cluster database has instances configured.

    • Set the CLUSTER_DATABASE initialization parameter to false. After the downgrade, you must set this initialization parameter back to TRUE.

20. At a system prompt, change to the ORACLE_HOME/rdbms/admin directory of the previous release.

21. Start SQL*Plus.

22. Connect to the database instance as a user with SYSDBA privileges.

23. Start up the instance:

    SQL> STARTUP UPGRADE
    

24. Set the system to spool results to a log file for later verification of success:

    SQL> SPOOL reload.log
    

25. Run catrelod.sql:

    SQL> @catrelod.sql
    

    The catrelod.sql script reloads the appropriate version of all of the database components in the downgraded database.

26. If you are downgrading to Oracle Database 11g Release 1 (11.1.0.6), run the xsrelod.sql script:

    SQL> @xsrelod.sql
    

    Running the xsrelod.sql script avoids the following error:

    PLS-00306: wrong number or types of arguments in call
    to 'INVALIDATE_DSD_CACHE' DBMS_XS_DATA_SECURITY_EVENTS
    PL/SQL: Statement ignored
    

27. If you are downgrading to Oracle Database 10g Release 1 (10.1.0.5) and you have XDB in your database, then run the following script after running catrelod.sql:

    @dbmsxdbt.sql
    

28. Turn off the spooling of script results to the log file:

    SQL> SPOOL OFF
    

    Then, check the spool file and verify that the packages and procedures compiled successfully. You named the spool file in Step 24; the suggested name was reload.log. Correct any problems you find in this file and rerun the appropriate script if necessary.

29. Shut down and restart the instance for normal operation:

    SQL> SHUTDOWN IMMEDIATE
    SQL> STARTUP
    

    You might be required to use the PFILE option to specify the location of your initialization parameter file.

30. Perform this step if the database is configured for Oracle Label Security and you are downgrading to Oracle Database 10g Release 1 (10.1).

    1. Copy the olstrig.sql script from the Oracle Database 11g Release 2 (11.2) Oracle home to the Oracle home of the version to which the database is to be downgraded.

    2. Run olstrig.sql to re-create DML triggers on tables with Oracle Label Security policies.

       SQL> @olstrig.sql
       

    See the Oracle Label Security Administrator's Guide for more information.

31. Run the utlrp.sql script:

    SQL> @utlrp.sql
    

    The utlrp.sql script recompiles all existing PL/SQL modules that were previously in an INVALID state, such as packages, procedures, types, and so on.

32. Exit SQL*Plus.

Your database is now downgraded.

Perform Post-Downgrade Tasks

This section discusses tasks that might be required after downgrading a database. This section contains the following topics:

• Downgrading Oracle Clusterware Configuration

• Restoring Oracle Enterprise Manager

  • Single-Instance Oracle Database Without ASM

  • Oracle RAC Database Without ASM

  • Single-Instance Oracle ASM Instance

  • Oracle RAC ASM Instance

  • Single-Instance Oracle Database With ASM

  • Oracle RAC Database and ASM Instance

• Enabling Oracle Database Vault

• Reload Oracle Application Express

111Home/bin/emca -restore db

111Home/bin/emca -restore db -cluster

111Home/bin/emca -restore asm

111Home/bin/emca -restore asm -cluster

111Home/bin/emca -restore db_asm

111Home/bin/emca -restore db_asm -cluster

> emca -restore db
 
STARTED EMCA at Mar 23, 2007 2:44:17 PM
EM Configuration Assistant, Version 11.1.0.3.0 Production
Copyright (c) 2003, 2005, Oracle.  All rights reserved.
Enter the following information:
Mar 23, 2007 2:44:17 PM oracle.sysman.emcp.util.GeneralUtil initSQLEngine
SEVERE: No SID specified
ORACLE_HOME for the database to be restored: /scratch/oracle/10.2.0/product/db_1
Database SID: DB102
Listener port number: 1521
Password for SYS user:  oracle
Do you wish to continue? [yes(Y)/no(N)]: Y
Mar 23, 2007 2:47:29 PM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /scratch/oracle/cfgtoollogs/emca/DB102/emca_2007_03_23_14_44_17.log.
Mar 23, 2007 2:47:30 PM oracle.sysman.emcp.util.DBControlUtil stopOMS
INFO: Stopping Database Control (this may take a while) ...
Mar 23, 2007 2:47:41 PM oracle.sysman.emcp.util.DBControlUtil startOMS
INFO: Starting Database Control (this may take a while) ...
Mar 23, 2007 2:48:06 PM oracle.sysman.emcp.EMDBPostConfig performRestore
INFO: Database Control started successfully
Mar 23, 2007 2:48:06 PM oracle.sysman.emcp.EMDBPostConfig performRestore
INFO: >>>> The Database Control URL is http://stadd17.us.oracle.com:1158/em <<<<<<
Enterprise Manager configuration completed successfully
FINISHED EMCA at Mar 23, 2007 2:48:06 PM

ALTER TRIGGER DVSYS.DV_BEFORE_DDL_TRG ENABLE;
ALTER TRIGGER DVSYS.DV_AFTER_DDL_TRG ENABLE;