02:00:50,586 WARN [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (liferay/scheduler_dispatch-634) Destroying connection that is not valid, due to the following exception: oracle.jdbc.driver.T4CConnection@68e54de: java.sql.SQLException: pingDatabase failed status=-2
The message denotes that somehow jboss can't establish a connection with the database. This can be caused for many reasons, but there are a checklist that
1. Try to ping/telnet and sqlplus the database, with the ip/port list and the hostname.
2. Check the CPU usage while the WARN messages are printed on log files.
The setup of the isolation level has to be made on datasource subsystem. You have edited the infinispan subsystem that handles isolation of the cache not
the database transaction isolation. The directive you should edit is <transaction-isolation>LEVEL<transaction-isolation>
Where LEVEL is one of these:
Hope it helps