MetadataMappingService fails to add an edge for a process instance

2015-08-14 15:31:00,950 INFO  - [ActiveMQ Session Task:] ~ Adding process instance: pig-sleep-process/2015-07-28T07:40Z (InstanceRelationshipGraphBuilder:74)
2015-08-14 15:31:00,951 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pig-sleep-process/2015-07-28T07:40Z, type=PROCESS_INSTANCE (RelationshipGraphBuilder:87)
2015-08-14 15:31:00,957 DEBUG - [ActiveMQ Session Task:] ~ Creating a new vertex for: name=pig-sleep-process/2015-07-28T07:40Z, type=PROCESS_INSTANCE (RelationshipGraphBuilder:101)
2015-08-14 15:31:00,981 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pig-sleep-process, type=PROCESS_ENTITY (RelationshipGraphBuilder:87)
2015-08-14 15:31:00,984 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=pig-sleep-process, type=PROCESS_ENTITY, v=v[16] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:00,988 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=local, type=CLUSTER_ENTITY (RelationshipGraphBuilder:87)
2015-08-14 15:31:00,990 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=local, type=CLUSTER_ENTITY, v=v[4] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:00,992 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pallavi.rao, type=USER (RelationshipGraphBuilder:87)
2015-08-14 15:31:00,995 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=pallavi.rao, type=USER, v=v[8] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:00,997 INFO  - [ActiveMQ Session Task:] ~ Computing feed instance for : name= IGNORE path= IGNORE, in cluster: local (InstanceRelationshipGraphBuilder:243)
2015-08-14 15:31:01,009 INFO  - [ActiveMQ Session Task:] ~ Adding process instance: pig-sleep-process/2015-07-28T07:40Z (InstanceRelationshipGraphBuilder:74)
2015-08-14 15:31:01,009 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pig-sleep-process/2015-07-28T07:40Z, type=PROCESS_INSTANCE (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,012 DEBUG - [ActiveMQ Session Task:] ~ Creating a new vertex for: name=pig-sleep-process/2015-07-28T07:40Z, type=PROCESS_INSTANCE (RelationshipGraphBuilder:101)
2015-08-14 15:31:01,033 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pig-sleep-process, type=PROCESS_ENTITY (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,035 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=pig-sleep-process, type=PROCESS_ENTITY, v=v[16] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:01,039 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=local, type=CLUSTER_ENTITY (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,041 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=local, type=CLUSTER_ENTITY, v=v[4] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:01,043 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pallavi.rao, type=USER (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,044 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=pallavi.rao, type=USER, v=v[8] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:01,047 INFO  - [ActiveMQ Session Task:] ~ Computing feed instance for : name= IGNORE path= IGNORE, in cluster: local (InstanceRelationshipGraphBuilder:243)
2015-08-14 15:31:01,073 INFO  - [ActiveMQ Session Task:] ~ Adding process instance: pig-sleep-process/2015-07-28T07:40Z (InstanceRelationshipGraphBuilder:74)
2015-08-14 15:31:01,073 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pig-sleep-process/2015-07-28T07:40Z, type=PROCESS_INSTANCE (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,076 DEBUG - [ActiveMQ Session Task:] ~ Creating a new vertex for: name=pig-sleep-process/2015-07-28T07:40Z, type=PROCESS_INSTANCE (RelationshipGraphBuilder:101)
2015-08-14 15:31:01,096 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pig-sleep-process, type=PROCESS_ENTITY (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,098 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=pig-sleep-process, type=PROCESS_ENTITY, v=v[16] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:01,102 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=local, type=CLUSTER_ENTITY (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,103 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=local, type=CLUSTER_ENTITY, v=v[4] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:01,105 DEBUG - [ActiveMQ Session Task:] ~ Finding vertex for: name=pallavi.rao, type=USER (RelationshipGraphBuilder:87)
2015-08-14 15:31:01,108 INFO  - [ActiveMQ Session Task:] ~ Vertex exists? name=pallavi.rao, type=USER, v=v[8] (InstanceRelationshipGraphBuilder:129)
2015-08-14 15:31:01,110 INFO  - [ActiveMQ Session Task:] ~ Computing feed instance for : name= IGNORE path= IGNORE, in cluster: local (InstanceRelationshipGraphBuilder:243)
2015-08-14 15:31:01,111 ERROR - [ActiveMQ Session Task:] ~ Error in listener org.apache.falcon.metadata.MetadataMappingService (WorkflowJobEndNotificationService:226)
org.apache.falcon.FalconException: java.lang.RuntimeException: java.lang.NullPointerException
	at org.apache.falcon.metadata.MetadataMappingService.onSuccess(MetadataMappingService.java:274)
	at org.apache.falcon.workflow.WorkflowJobEndNotificationService.notifyWorkflowEnd(WorkflowJobEndNotificationService.java:222)
	at org.apache.falcon.workflow.WorkflowJobEndNotificationService.notifySuccess(WorkflowJobEndNotificationService.java:105)
	at org.apache.falcon.messaging.JMSMessageConsumer.invokeListener(JMSMessageConsumer.java:169)
	at org.apache.falcon.messaging.JMSMessageConsumer.onMessage(JMSMessageConsumer.java:112)
	at org.apache.activemq.ActiveMQMessageConsumer.dispatch(ActiveMQMessageConsumer.java:1229)
	at org.apache.activemq.ActiveMQSessionExecutor.dispatch(ActiveMQSessionExecutor.java:134)
	at org.apache.activemq.ActiveMQSessionExecutor.iterate(ActiveMQSessionExecutor.java:205)
	at org.apache.activemq.thread.PooledTaskRunner.runTask(PooledTaskRunner.java:122)
	at org.apache.activemq.thread.PooledTaskRunner$1.run(PooledTaskRunner.java:43)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: java.lang.NullPointerException
	at com.tinkerpop.blueprints.util.TransactionRetryStrategy$AbstractRetryStrategy.execute(TransactionRetryStrategy.java:176)
	at com.tinkerpop.blueprints.util.TransactionRetryHelper.use(TransactionRetryHelper.java:115)
	at com.tinkerpop.blueprints.util.TransactionRetryHelper.exponentialBackoff(TransactionRetryHelper.java:94)
	at org.apache.falcon.metadata.MetadataMappingService.onSuccess(MetadataMappingService.java:263)
	... 12 more
Caused by: java.lang.NullPointerException
	at org.apache.falcon.entity.FeedHelper.getCluster(FeedHelper.java:80)
	at org.apache.falcon.entity.FeedHelper.getStorageType(FeedHelper.java:235)
	at org.apache.falcon.metadata.InstanceRelationshipGraphBuilder.getFeedInstanceName(InstanceRelationshipGraphBuilder.java:280)
	at org.apache.falcon.metadata.InstanceRelationshipGraphBuilder.addFeedInstance(InstanceRelationshipGraphBuilder.java:245)
	at org.apache.falcon.metadata.InstanceRelationshipGraphBuilder.addOutputFeedInstances(InstanceRelationshipGraphBuilder.java:151)
	at org.apache.falcon.metadata.MetadataMappingService.onProcessInstanceExecuted(MetadataMappingService.java:313)
	at org.apache.falcon.metadata.MetadataMappingService.onSuccessfulExecution(MetadataMappingService.java:282)
	at org.apache.falcon.metadata.MetadataMappingService.access$100(MetadataMappingService.java:53)
	at org.apache.falcon.metadata.MetadataMappingService$3.execute(MetadataMappingService.java:267)
	at org.apache.falcon.metadata.MetadataMappingService$3.execute(MetadataMappingService.java:264)
	at com.tinkerpop.blueprints.util.TransactionRetryStrategy$AbstractRetryStrategy.execute(TransactionRetryStrategy.java:146)