Hi,
It took me a long time to figure the problem out, and I think it may be a bug
in kafka-streams, or at least something that could have a better log warning
message.
I’m using the high-level API. I get errors of the form “Partition XXX is not
assigned to any tasks: {}”, even though I was using that topic. In my original
code, I was using KTables, but I managed to reproduce the problem in the code
below with simple KStream processing.
I have two seemingly independent subtopologies. The only shared element is that
they share a Store. (In my original code, one topology is reading a topic with
update messages that get applied to the store, while the other topology uses
the data in the store to classify input data)
Before I added the second subtopology, the first subtopology worked fine. After
adding the second subtopology, I started getting the dreaded “Partition XXX is
not assigned to any tasks: {}” for the topic of the first subtopology.
As the second subtopology was a new feature (I had already populated the store
in another way), I had not yet created the input topic for the second
subtopology on my integration environment. It turns out that this is the reason
that the first subtopology fails. Because they share the same store, somehow
the subtopologies interact.
Below is a snippet from my log file, running the bug reporting code that I
posted below it.
The reproduce the problem using the bug reporting code, ensure that the topics
“number-in” and “number-out” exist, but “unknown-in” doesn’t exist.
Once the problem is clear, it is very easy to fix it: create the “unknown-in”
topic, and the code runs fine. But the reported warnings make no reference to
the real underlying problem.
I’ve tested the below code with kafka-streams version 1.0.1 on JDK8 1.8.0_132.
Best Regards.
Erwin Bolwidt
09:56:46.245 WARN o.a.k.s.p.i.StreamPartitionAssignor - stream-thread
[FooBar-1eab35bd-5198-4d24-8ce4-9f1ac9687764-StreamThread-1-consumer] No
partitions found for topic unknown-in
09:56:46.246 WARN o.a.k.s.p.i.StreamPartitionAssignor - stream-thread
[FooBar-1eab35bd-5198-4d24-8ce4-9f1ac9687764-StreamThread-1-consumer] Partition
number-in-0 is not assigned to any tasks: {}
09:56:46.247 INFO o.a.k.s.p.i.StreamPartitionAssignor - stream-thread
[FooBar-1eab35bd-5198-4d24-8ce4-9f1ac9687764-StreamThread-1-consumer] Assigned
tasks to clients as {1eab35bd-5198-4d24-8ce4-9f1ac9687764=[activeTasks: ([])
standbyTasks: ([]) assignedTasks: ([]) prevActiveTasks: ([]) prevAssignedTasks:
([0_0, 1_0]) capacity: 1]}.
09:56:46.248 WARN o.a.k.c.c.i.ConsumerCoordinator - [Consumer
clientId=FooBar-1eab35bd-5198-4d24-8ce4-9f1ac9687764-StreamThread-1-consumer,
groupId=FooBar] The following subscribed topics are not assigned to any
members: [number-in]
Code that reproduces the problem:
package bugreport;
import java.util.HashMap;
import java.util.Map;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.streams.Consumed;
import org.apache.kafka.streams.KafkaStreams;
import org.apache.kafka.streams.KeyValue;
import org.apache.kafka.streams.StreamsBuilder;
import org.apache.kafka.streams.StreamsConfig;
import org.apache.kafka.streams.Topology;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.Produced;
import org.apache.kafka.streams.kstream.Transformer;
import org.apache.kafka.streams.kstream.TransformerSupplier;
import org.apache.kafka.streams.processor.ProcessorContext;
import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
import org.apache.kafka.streams.state.KeyValueStore;
import org.apache.kafka.streams.state.StoreBuilder;
import org.apache.kafka.streams.state.Stores;
public class BugReportTwoTopologiesInteractionThroughStore {
private static final String STORE_NAME = "store";
static class TransformerAdapter<K, V, R> implements Transformer<K, V, R> {
@Override
public void init(ProcessorContext context) {
}
@Override
public void close() {
}
@Override
public R punctuate(long timestamp) {
return null;
}
@Override
public R transform(K key, V value) {
return null;
}
}
public static Map<String, Object> kafkaStreamsConfiguration() {
Map<String, Object> properties = new HashMap<>();
properties.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG,
"10.91.132.98:9092");
properties.put(StreamsConfig.APPLICATION_ID_CONFIG, "FooBar");
properties.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 100);
properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
return properties;
}
public static void constructTopology(StreamsBuilder builder, String
topicIn, String topicOut, int base) {
KStream<Long, Long> stream = builder.stream(topicIn,
Consumed.with(Serdes.Long(), Serdes.Long()));
stream = stream.transform(new TransformerSupplier<Long, Long,
KeyValue<Long, Long>>() {
@Override
public Transformer<Long, Long, KeyValue<Long, Long>> get() {
return new TransformerAdapter<Long, Long, KeyValue<Long,
Long>>() {
@Override
public KeyValue<Long, Long> transform(Long key, Long value)
{
return new KeyValue<Long, Long>(key, base - value);
}
};
}
}, STORE_NAME);
stream.to(topicOut, Produced.with(Serdes.Long(), Serdes.Long()));
}
public static void main(String[] args) {
StreamsBuilder builder = new StreamsBuilder();
KeyValueBytesStoreSupplier storeSupplier =
Stores.persistentKeyValueStore(STORE_NAME);
StoreBuilder<KeyValueStore<String, String>> storeBuilder =
Stores.keyValueStoreBuilder(storeSupplier,
Serdes.String(), Serdes.String());
builder.addStateStore(storeBuilder);
constructTopology(builder, "number-in", "number-out", 10);
constructTopology(builder, "unknown-in", "unknown-out", 20);
Topology topology = builder.build();
KafkaStreams streams = new KafkaStreams(topology, new
StreamsConfig(kafkaStreamsConfiguration()));
streams.start();
}
}
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