mod_oc4j: Failed to find a failover oc4j process for session request for destination

mod_oc4j: Failed to find a failover oc4j process for session request for destination


Have encountered an issues with oacore crashing in R12 Oracle Applications frequently:

Error Message in error_log:
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mod_oc4j: Failed to find a failover oc4j process for session request for destination: application://oacore (no island or jgroup).


Finding:
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The error 'mod_oc4j Failed to find a failover oc4j process for session request for destination' indicates that a session request was received by the Process Manger (PM). The PM was unable to find a java process to route the session to which would be defined as a "island" or "jgroup" and it failed.

The error indicates for some reason the OC4J process has become non responsive to the point where the PM has determined it failed or is no longer available. This error usually occurs when OHS (mod_oc4j) is not able to communicate ( over AJP ) with OC4J.

There are multiple reasons why this error may have happened: Some common reasons are

1. Load: e.g. Too many clients connecting to the application :
 - The number of requests are high enough that the process cannot respond to new requests prior to reaching the timeout period.

2. Performance: Heavily loaded JVM or Lack of enough memory for JVM
  - The OC4J oacore JVM processes in the middle tier are heavily loaded
  - High number of jdbc connections with database there by increasing the number of threads on the java process.


Suggestion:
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Increae the OACore Heap Configuration to 512/1024 in opmn.xml

Change the below entry in opmn.xml(also modify the entry in xml file) and Bounce the opmn services.

From:

<data id="java-options" value="-server -verbose:gc -Xmx512M -Xms512M -XX:MaxPermSize=160M -XX:NewRatio=2
To:


<data id="java-options" value="-server -verbose:gc -Xmx1024M -Xms1024M -XX:MaxPermSize=256M -XX:NewRatio=2


For More Information Please Ref:Guidelines to setup the JVM in Apps Ebusiness Suite 11i and R12 [ID 362851.1]