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Kafka >> mail # user >> Sometimes get no message streams in consumer


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Sometimes get no message streams in consumer
Hey gang, I have a strange intermittent issue with our 0.7.2 consumers that is perpelxing me:

It seems like, sometimes very infrequently, when restarting our Consumer fleet, some consumers threads just fail to start. The consumer connector itself starts fine, and seems to be involved in subsequent rebalances, but based on the logging I'm seeing, it looks like our one call to ConsumerConnector.createMessageStreams is returning an empty map.  

Is that something that should happen normally and should we be retrying in our calling code? Our consumer code looks like this:

Map<String, List<KafkaStream<Message>>> topicMessageStreams =  
   fConsumerConnector.createMessageStreams( getTopicMap() );

for( Map.Entry<String, List<KafkaStream<Message>>> entry : topicMessageStreams.entrySet() )  
{
final String topicName = entry.getKey();  
log.info( "starting stream for topic: " + topicName );
final KafkaStream<Message> stream = entry.getValue().get(0);

….

Are we doing anything dumb here? In the case I described, we're never getting the "starting stream for topic: " message in our log output, so my only guess is that createMessageStreams is returning an empty map.  

Thanks in advance guys!

--  
Ian Friedman
 
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB