Hi,
I accidentally created a scenario where I was attempting to produce a
record to a partition that did not exist, because I was manually overriding
the destination partition, and I noticed that the producer.send blocked for
60s (producer property max.block.ms). During this time the producer was
internally polling the broker with metadata requests, I assume to wait for
this partition to eventually exist. After the timeout the failure is
returned. I've since learned the same thing happens if the topic does not
exist.
I have a few questions:
Q: Why does the producer block in this scenario? It could "fail fast" if
the producer record contains incompatible topic metadata such as incorrect
topic name or invalid partition number.
Q: Should we consider adding a more informative error message that
indicates what the root cause of the problem is? For example, that the
partition does not exist.
Logs:
11:15:08.176 DEBUG [-thread | producer-1]
o.apache.kafka.clients.NetworkClient [Producer clientId=producer-1]
Sending metadata request (type=MetadataRequest, topics=topic-1-1) to node
localhost:33263 (id: 0 rack: null)
11:15:08.221 DEBUG [-thread | producer-1] o.a.k.c.producer.internals.Sender
[Producer clientId=producer-1] ProducerId: 0; Set last ack'd sequence
number for topic-partition topic-1-1-1 to 0
11:15:08.270 DEBUG [-thread | producer-1] o.a.k.c.producer.internals.Sender
[Producer clientId=producer-1] ProducerId: 0; Set last ack'd sequence
number for topic-partition topic-1-1-0 to 0
11:15:08.273 DEBUG [-thread | producer-1] org.apache.kafka.clients.Metadata
Updated cluster metadata version 3 to Cluster(id =
5zRzH-78RkmjmB5Ud8J6VQ, nodes = [localhost:33263 (id: 0 rack: null)],
partitions = [Partition(topic = topic-1-1, partition = 1, leader = 0,
replicas = [0], isr = [0], offlineReplicas = []), Partition(topic =
topic-1-1, partition = 0, leader = 0, replicas = [0], isr = [0],
offlineReplicas = [])], controller = localhost:33263 (id: 0 rack: null))
11:15:08.372 DEBUG [-thread | producer-1]
o.apache.kafka.clients.NetworkClient [Producer clientId=producer-1]
Sending metadata request (type=MetadataRequest, topics=topic-1-1) to node
localhost:33263 (id: 0 rack: null)
11:15:08.374 DEBUG [-thread | producer-1] org.apache.kafka.clients.Metadata
Updated cluster metadata version 4 to Cluster(id =
5zRzH-78RkmjmB5Ud8J6VQ, nodes = [localhost:33263 (id: 0 rack: null)],
partitions = [Partition(topic = topic-1-1, partition = 1, leader = 0,
replicas = [0], isr = [0], offlineReplicas = []), Partition(topic =
topic-1-1, partition = 0, leader = 0, replicas = [0], isr = [0],
offlineReplicas = [])], controller = localhost:33263 (id: 0 rack: null))
11:15:08.474 DEBUG [-thread | producer-1]
o.apache.kafka.clients.NetworkClient [Producer clientId=producer-1]
Sending metadata request (type=MetadataRequest, topics=topic-1-1) to node
localhost:33263 (id: 0 rack: null)
11:15:08.478 DEBUG [-thread | producer-1] org.apache.kafka.clients.Metadata
Updated cluster metadata version 5 to Cluster(id =
5zRzH-78RkmjmB5Ud8J6VQ, nodes = [localhost:33263 (id: 0 rack: null)],
partitions = [Partition(topic = topic-1-1, partition = 1, leader = 0,
replicas = [0], isr = [0], offlineReplicas = []), Partition(topic =
topic-1-1, partition = 0, leader = 0, replicas = [0], isr = [0],
offlineReplicas = [])], controller = localhost:33263 (id: 0 rack: null))
...
11:16:08.095 DEBUG [-thread | producer-1]
o.apache.kafka.clients.NetworkClient [Producer clientId=producer-1]
Sending metadata request (type=MetadataRequest, topics=topic-1-1) to node
localhost:33263 (id: 0 rack: null)
11:16:08.096 DEBUG [-thread | producer-1] org.apache.kafka.clients.Metadata
Updated cluster metadata version 582 to Cluster(id =
5zRzH-78RkmjmB5Ud8J6VQ, nodes = [localhost:33263 (id: 0 rack: null)],
partitions = [Partition(topic = topic-1-1, partition = 1, leader = 0,
replicas = [0], isr = [0], offlineReplicas = []), Partition(topic =
topic-1-1, partition = 0, leader = 0, replicas = [0], isr = [0],
offlineReplicas = [])], controller = localhost:33263 (id: 0 rack: null))
11:16:08.099 DEBUG [default-dispatcher-7]
o.a.k.clients.producer.KafkaProducer [Producer clientId=producer-1]
Exception occurred during message send:
org.apache.kafka.common.errors.TimeoutException: Topic topic-1-1 not
present in metadata after 60000 ms.
--
Sean Glover
Principal Engineer, Alpakka, Lightbend, Inc. <https://lightbend.com>
@seg1o <https://twitter.com/seg1o>, in/seanaglover
<https://www.linkedin.com/in/seanaglover/>
