Steps to install companion CD 10gR2 over 10.2.0.4 Oracle Home

I got a new job in the beginning of this year. The configuration of the E-Business 11.5.10.2 is quite complex. There are two web/forms nodes, two concurrent manager and administration server nodes. Database is on the two nodes RAC. When I just joined the company as a DBA, the database is on 32-bit system. You know the performance is a problem.

I found another problem for our system. The Companion CD for 10gR2 was never installed. As we have applied the 10gR2 patchset 3 (10.2.0.4), we can not run installer from the Companion CD. Here are the steps to get this done. Run step 1 to 5 on one node.

shutdown apps, database and listener.

start OUI from $ORACLE_HOME/oui/bin/runInstaller –ignoreSysPrereqs (which is version 10.2.0.4) (see Note 741643.1 for not using OUI from companion CD at 10.2.0.1)

(pick middle option: Oracle Database 10g Products 10.2.0.1)

companion CD binary code is at /share/oracle/install/lnx64_10gr2/companion/stage/products.xml

After installed companion CD 10.2.0.1, need to apply 10gR2 patchset 3 (10.2.0.4) again (see Note 757129.1).

Start OUI at:
/share/oracle/install/lnx64_10gr2/10204/Disk1/runInstaller -ignoreSysPrereqs

Post installation tasks (on one node only) (need about 1.5 hours)
comment out cluster_database in init.ora
startup database: startup upgrade;
spool /tmp/patch.log
@?/rdbms/admin/catupgrd.sql
Spool off
Review patch.log, check for error, warning, fail etc.
Shutdown immediate
Uncomment cluster_database in init.ora
Startup
@?/rdbms/admin/utlrp.sql
Select comp_name,version,status from sys.dba_registry, make sure all comp are valid.

shutdown database and apply the one-off patches (check if these patches got reversed. Opatch lsinventory, otherwise, skip step 7)
$PATCHHOME/rdbms/p6139856, p6471770, p6971433, p7331323, p7441176 and p8479537.