How to apply patch in Oracle Apps R12.2 A step by step guide

From R12.2 onwards oracle has introduced online patching functionality.
Online Patching
Online patching uses the latest feature of the Oracle database 11gR2 which is called “Edition Based 
Redefinition” and also uses multiple file systems on the application side. During online patching, business application users continue using the Oracle application and simultaneously a patch or a sequence of patches can be applied to another edition of the same database and application. Another edition here means another exact copy of database and application. And once the patching is complete the users are switched over to a patched file system/database in cutover phase by just bouncing middle tier services.

File System
A R12.2.0 is installed with three file Systems.

1.FS1 – Production file system that is used by application users when system is being patched.

2.FS2 – Exact copy of production used by the patching tool. This copy is patched by the patching tool. It gets synchronised with FS1 by the patching tool before it gets updated by a patch. When patching is complete, the patching tool swaps the FS1 and FS2 file systems. FS2 file system becomes FS1 and FS1 is switched to FS2. This way, FS2 is again ready to be used for any future patching tasks.

3.FS-NE – This is a non-edition file system which stores data that is stored in a file system like data import/export files, report out and log files.

Phases of ADOP(online patching)

ADPATCH utility is no longer used in R12.2.0 and is being replaced by ADOP – AD Online Patching. There are five phases or life cycles of ADOP which are:

a) PREPARE

b) APPLY

c) FINALIZE

d) CUTOVER

e) CLEANUP

Steps:-

1. Download the patch and unzip on patch_top and go through the read me to check,what its going to do.
2. Prepare the system for patching
   a. Run environment file(optional)
   Note: The adop utility sets its own environment. There is therefore no need to source the environment before running it.
   b.adop phase=prepare
3. Apply Phase -
   adop phase=apply patches=, workers=

After patch has been successfully applied,complete the patch cycle

4. Finalize phase - Used to perform the final patching operations that can be executed while the application is still online:

adop phase=finalize workers= (called automatically)

5. Cutover phase - Used to perform the transition to the patched environment:

adop phase=cutover workers=

6. Cleanup phase - Used to remove old objects that are no longer needed:
   adop phase=cleanup (called automatically)

Now synchronise the technology level between patch and run fc_clone.

7. adop phase=fs_clone

Abort phase - Used only if the online patching cycle needs to be terminated before completion:

$ adop phase=abort

Important: The abort phase can only be run after the prepare phase and before completion of the cutover phase. After the cutover phase completes, it is no longer possible to abort the online patching cycle.

Last two commands for adop

a. adop -help

b. adop -examples

Patch Log Files:-

To review the relevant log files after any patching operation. The adop log files are located on the non-editioned file system (fs_ne), under:

$NE_BASE/EBSapps/log/adop//__//log