You can directly upgrade an Oracle database from version 18.104.22.168 or higher, directly to 11g
Open database in Upgrade mode:
Pre-Upgrade information tool:
- Precursor to the upgrade.
- Generated report on required and recommended changes to make..
- Generally increasing tablespace sizes or remove parameters.
- Makes actual changes to the database.
- If it is stopped or failes, it can be rerun.
- Shuts down database on completion.
Restart the database in normal mode.
Upgrade status script:
- Verifies that all components have been successfully upgraded.
- If any components have failed, rerun the catupgrd.sql script.
Post Upgrade actions script:
- New in 11g.
- Performs upgrade actions that don’t require upgrade mode.
- Can be ran at the same time as catuppst.sql.
- It recompiles INVALID objects.
catdwgrd.sql would carry out the downgrade to the previous version if you needed it.
The Database Upgrade Assistant (DBUA)
Can upgrade database and ASM instances simultaniously.
Faster at the end as it uses parallel compilation on multi-CPU systems
Allows you to upgrade from XE to 11g
You can move datafiles around as part of the upgrade.
The DBUA asks you to supply the ORACLE_BASE parameter which it uses to derive default db locations as well as the DIAGNOSTIC_DEST parameter.
If you specify AUTOEXTEND on the command line, Oracle will allow tablespaces to AUTOEXTEND then sets them back to their original settings after the upgrade.
The compatible parameter
The compatible parameter controls whether a lot of functionality is available.
The default value is: 11.1.0 or 11.2.0 and the minimum allowed value is 10.0.0