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https://issues.apache.org/jira/browse/FLINK-10122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16583385#comment-16583385
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ASF GitHub Bot commented on FLINK-10122:
----------------------------------------
tzulitai commented on a change in pull request #6537: [FLINK-10122]
KafkaConsumer should use partitionable state over union state if partition
discovery is not active
URL: https://github.com/apache/flink/pull/6537#discussion_r210808465
##########
File path:
flink-connectors/flink-connector-kafka-base/src/main/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumerBase.java
##########
@@ -783,30 +779,26 @@ public final void
initializeState(FunctionInitializationContext context) throws
OperatorStateStore stateStore = context.getOperatorStateStore();
- ListState<Tuple2<KafkaTopicPartition, Long>>
oldRoundRobinListState =
-
stateStore.getSerializableListState(DefaultOperatorStateBackend.DEFAULT_OPERATOR_STATE_NAME);
+ final TypeInformation<Tuple2<KafkaTopicPartition, Long>>
offsetStateTypeInfo =
+ TypeInformation.of(new
TypeHint<Tuple2<KafkaTopicPartition, Long>>() {});
- this.unionOffsetStates = stateStore.getUnionListState(new
ListStateDescriptor<>(
- OFFSETS_STATE_NAME,
- TypeInformation.of(new
TypeHint<Tuple2<KafkaTopicPartition, Long>>() {})));
+ ListStateDescriptor<Tuple2<KafkaTopicPartition, Long>>
offsetStateDescriptor =
+ new ListStateDescriptor<>(OFFSETS_STATE_NAME,
offsetStateTypeInfo);
- if (context.isRestored() && !restoredFromOldState) {
- restoredState = new TreeMap<>(new
KafkaTopicPartition.Comparator());
+ this.offsetsState =
+ discoveryIntervalMillis != PARTITION_DISCOVERY_DISABLED
?
+
stateStore.getUnionListState(offsetStateDescriptor) :
stateStore.getListState(offsetStateDescriptor);
Review comment:
I think this is a "behaviour break".
Before, the user was free to switch between enabling / disabling partition
discovery on each restart for the job.
Now, with this change, we can't really do that, because changing the
distribution scheme of the same registered state isn't allowed.
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> KafkaConsumer should use partitionable state over union state if partition
> discovery is not active
> --------------------------------------------------------------------------------------------------
>
> Key: FLINK-10122
> URL: https://issues.apache.org/jira/browse/FLINK-10122
> Project: Flink
> Issue Type: Improvement
> Components: Kafka Connector
> Reporter: Stefan Richter
> Assignee: Stefan Richter
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.7.0
>
>
> KafkaConsumer store its offsets state always as union state. I think this is
> only required in the case that partition discovery is active. For jobs with a
> very high parallelism, the union state can lead to prohibitively expensive
> deployments. For example, a job with 2000 source and a total of 10MB
> checkpointed union state offsets state would have to ship ~ 2000 x 10MB =
> 20GB of state. With partitionable state, it would have to ship ~10MB.
> For now, I would suggest to go back to partitionable state in case that
> partition discovery is not active. In the long run, I have some ideas for
> more efficient partitioning schemes that would also work for active discovery.
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