Oracle FAQ: Patching
1. OPatch automatically detects and reports the conflicts before the start patching.
2. We can use the -force option to override this failure. But generally , we must not use -force option.
3. If we specify -force, the installer first rolls back any conflicting patches and then proceeds with the installation of the desired interim patch.
4. We may experience a bug conflict and might want to remove the conflicting patch.
5. During patch installation, OPatch saves copies of all the files that were replaced by the new patch before the new versions of these files are loaded, and stores them in $ORACLE_HOME/.patch_storage.
6. These saved files are called rollback files and are key to making patch rollback possible.
7. When you roll back a patch, these rollback files are restored to the system.
8. $ OPatch/opatch rollback -id patch_id
1. In this case, we can not rollback the patches. Only supported solution is The missing directories and files can be restored from a backup of the ORACLE_HOME.
2. If no backups exist then re-install the $ORACLE_HOME.
3. Clone from another ORACLE_HOME of a like installation.