Topicmetadata response miss some partitions information sometimes

[ChenHongHai]

We have one topic with 4 partitions, but sometimes only get metadata of 2 
partitions, did anyone meet this kind of situation before?If some partition has 
no leader at that moment, will it cause this problem?     How to make some 
partition has no leader?If 6 brokers has some partitions of the topic, will 
they return same result?  Do I need try all of them and merge the result?

     SimpleConsumer consumer = consumerPool.getConsumer(seed.host, seed.port, 
connectionTimeOut, consumerBufferSize, "refreshPartitionMeta");                
List<String> topics = new ArrayList<String>() {{                    add(topic); 
               }};                TopicMetadataResponse resp = 
consumer.send(new TopicMetadataRequest(topics));                
List<TopicMetadata> metaData = resp.topicsMetadata();
                for (TopicMetadata item : metaData) {                    
if(item.errorCode() != kafka.common.ErrorMapping.NoError())                     
   LOG.error(String.format("Something wrong with topic metadata for topic: %s 
error code: %d ", item.topic(), item.errorCode() ));                    for 
(PartitionMetadata part : item.partitionsMetadata()) {                        
partitionMeta.put(part.partitionId(), part);                                    
     }                }