Hi Folks!! Well its been really a long time since i posted on my blog. Today i would like to discuss on Implementing PCP (Parallel Concurrent Processing) in a RAC/NON RAC Environment. There are plenty of articles on metalink on Implementing PCP but i will be discussing the fine grain details of PCP in this article.
In a PCP Implementation as we all know we have an Internal Monitor running on each Concurrent Manager Node, Internal Monitor is like a local police monitoring the process on the respective concurrent tier. Oracle introduced a new process called "REVIVER" post ATG_PF.H RUP4 and Release 12 onwards. The job of reviver to restart Internal Concurrent Manager in case of a lost of database connection. You can enable the reviver by turning the context variable flag to enabled in Autoconfig XML File "s_cp_reviver". Review Metalink Note 466752.1 for more information on FND Reviver.
In PCP Implementation when your concurrent tier and database tier are different (which is many RAC Implementations Yes) then you have two options for providing High Availability for the Concurrent Processes
1. If you turn Profile Option "Concurrent: PCP Instance Check" to ON then when your Database goes down then the concurrent managers connecting to the database node which went down will failover to the failover node defined at the concurrent manager level
2. If you turn Profile Option "Concurrent: PCP Instance Check" to OFF then when your Database goes down then the Reviver Process on the Middle Tier tries to restart the Internal Concurrent Manager by connecting to the next surviving database node
Similarly if your Concurrent Tier goes down the concurrent manager should failover after 2-3 PMON Cycles, however if you notice that managers didnt failover then Login to OAM and make the apps tier which went down "Offline"
Login -> OAM -> Click on the Apps Tier which went down -> Turn it "Offline"
