How to determine if OACore JVM Sizing is Appropriate or Not

How to determine if OACore JVM Sizing is Appropriate or Not

cd $LOG_HOME/ora/10.1.3/opmn/
ls -ltr default_group~oacore*

grep 'Full GC' default_group~oacore* | wc -l
grep 'Unloading class' default_group~oacore* | grep 'Full GC' | wc -l

If you see there are multiple cases when Full GC is happening then, it is understood that JVM sizing in not proper.

Take following actions for this:
1. Increase the Number of OACore JVMs
2. Increase the JVM Heap Size
3. Make sure you are not using many parallel thread for GC.

Read the following for Sizing recommendations:
http://mkkoracleapps.blogspot.co.uk/2013/07/modoc4j-failed-to-find-failover-oc4j.html

Flush Shared Pool and Buffer Cache

SQL> ALTER PACKAGE FND_SSO_REGISTRATION COMPILE SPECIFICATION;
Package altered.

SQL> ALTER PACKAGE FND_SSO_REGISTRATION COMPILE BODY;
Package body altered.

SQL> ALTER PACKAGE FND_LDAP_WRAPPER COMPILE SPECIFICATION;
Package altered.

SQL> ALTER PACKAGE FND_LDAP_WRAPPER COMPILE BODY;
Package body altered.

SQL> show user;
USER is "SYS"

SQL> alter system flush buffer_cache;
System altered.

SQL> alter system flush shared_pool;
System altered.