Hello Apache Kafka community,
In the new consumer I encountered unexpected behavior. After constructing
KafakConsumer instance with configured consumer rebalance callback handler,
and subscribing to a topic with "consumer.subscribe(topic)", retrieving
subscriptions would return empty set and callback handler would not get
called (no partitions ever assigned or revoked), no matter how long
instance was up.
Then I found by inspecting KafkaConsumer code that partition assignment
will only be triggered on first poll, pollOnce has:
// ensure we have partitions assigned if we expect to
if (subscriptions.partitionsAutoAssigned())
coordinator.ensurePartitionAssignment();
Would it make sense to include this fragment in KafkaConsumer.subscriptions
accessor as well?
Kind regards,
Stevo Slavic.
