One or more post-processing actions failed. Consult the OPP service log for details / Java heap space

Query for the logfile:

SELECT fcpp.concurrent_request_id req_id, fcp.node_name, fcp.logfile_name
FROM fnd_conc_pp_actions fcpp, fnd_concurrent_processes fcp
WHERE fcpp.processor_id = fcp.concurrent_process_id
AND fcpp.action_type = 6
AND fcpp.concurrent_request_id = &request_id;

In my case:

/d01/applprod/inst/apps/PROD_server077/logs/appl/conc/log/FNDOPP281472.txt

java.lang.reflect.InvocationTargetException

Caused by: oracle.xdo.parser.v2.XPathException: Extension function error: Error invoking 'ms_format_number':'java.lang.OutOfMemoryError: Java heap space'

As a workaround we killed the OPP process:

ps -ef | grep OPP

kill -9 1943

Permanent Solution:

We increased the Java heap size from 1024M to 2048M.
a. Bring down the concurrent managers.

b. Use the Update statement below, for example:
update FND_CP_SERVICES
set DEVELOPER_PARAMETERS = 'J:oracle.apps.fnd.cp.gsf.GSMServiceController:-mx2048m'
where SERVICE_ID = (select MANAGER_TYPE from FND_CONCURRENT_QUEUES
where CONCURRENT_QUEUE_NAME = 'FNDCPOPP');

c. Bring concurrent managers up again