How to deinstall “old” SW after 11.2.0.2 has been applied?

I’m still learning continuously new things. On my test box I’ve installed 11.2.0.2 a few weeks ago in-place which is not our recommended solution – and can be quite tricky with 11.2.0.2. But I was running out of space …

Customer have asked us for a looooooong time why we don’t deliver full release but patch sets which have to be applied to a base installation. Now this all has been changed with 11.2.0.2 as it is a full release. And that’s the new strategy: We force people to install into a separate $ORACLE_HOME. This is called (and recommended) an out-of-place patch upgrade. Which is the default for Grid Infrastructure as well beginning with 11.2.0.1 already.

You can still go “the old way” for the database installation but you’ll have to ‘detach‘ your current home from the OUI inventory first in order to be able to install into the existing one. Something we fully disrecommend as it will increase your downtime if anything fails.

Nevertheless the question came up at the upgrade workshop in Montreal (and you might have asked yourself as well already):
How do I deinstall the “old” software once I’m using the new 11.2.0.2 Oracle home???

My first thought: Hey, if it’s a Unix box simply ‘rm -rf‘ the directories 😉
Second thought: Use the OUI as it always did offer a ‘REMOVE‘ button to remove leftovers.
Third thought: Use the magic ‘X’ to deinstall similar to your iPhone (ok. we are not this far yet)

Lesson learned now (thanks Roy!):
There’s a deinstallation tool called ‘deinstall‘ available in your $ORACLE_HOME/deinstall directory. Please find a detailed description right here in the Oracle Database Installation Guide(s) for 11.2. It will work for the database, Clusterware and ASM. But you could download it separately from OTN as well as part of the software distribution.