Blog | Oct 2, 2013

Online Patching in R12.2

Online Patching in R12.2, one of the misconceptions is why we should use Online Patching and not hot Patching. Hot patching does patching on the Run File Edition which could cause Resource Busy Wait errors while Patch application in progress, online patching overcomes that issue.  The patching tool adop takes care of Phases like Prepare, Apply, Finalize, Cutover, and Cleanup.

Phase details are explained below:

• Copy the Production app Code
• Create a new Patch Edition in the DB (Using Edition-Based Redefinition)
• Apply One of more patches to the Patch Edition
• Compile invalid Objects
• Wait for a good downtime window
CutOver (This Phase requires Downtime):
• Restart application on Patch Edition
• Remove obsolete objects


A few key points to keep in mind:
• Oracle strongly suggests to apply Patches as Online Patch
• Avoid Hot Patching on Run Edition as Hot patching may corrupt data
• Always keep resource balancing in mind while performing Online patching, you should check Load on the system and assign numbers of workers which don't interfere with Online User Load to avoid Performance issue
• You can perform recloning of patch edition to remove any applied patch prior to CutOver phase just in case you applied any patch in error
• Make sure to perform Full Application Tier backup immediately after Online patching CutOver Phase, this will make sure your DB Tier and Apps Tier are in SYNC in case of restore/recovery needs.

Online patching method will reduce downtime significantly and patches can be applied to system anytime of the day without affecting any user. Next time we will review Online Patching in Multi Node architecture and use of few other AD tools.