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Posted to issues@storm.apache.org by "Xu Mingmin (JIRA)" <ji...@apache.org> on 2017/02/06 22:05:42 UTC
[jira] [Updated] (STORM-2340) fix At-Most-Once issue in KafkaSpout
[ https://issues.apache.org/jira/browse/STORM-2340?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Xu Mingmin updated STORM-2340:
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Description:
What's the issue?
When Storm topology is run on 'At-Most-Once' mode, with ack executor=0, KafkaSpout cannot emit records after some time.
What's the cause?
Function poll() controls whether it need to pull more data from Kafka cluster. With the condition !waitingToEmit() && numUncommittedOffsets < maxUncommittedOffsets, it's always FALSE after reaching threshold, as numUncommittedOffsets is creasing and never reset on 'At-Most-Once' mode.
What's the solution?
I change the condition to !waitingToEmit() && (numUncommittedOffsets < maxUncommittedOffsets || consumerAutoCommitMode), that return TRUE with AutoCommitMode regarding of UnCommittedOffset, see the comments inline.
Also, it's not required to track emitted(msgId) and numUncommittedOffsets with AutoCommitMode .
was:
What's the issue?
When Storm topology is run on 'At-Most-Once' mode, with ack executor=0, KafkaSpout cannot emit records after some time.
What's the cause?
Function poll() controls whether it need to pull more data from Kafka cluster. With the condition !waitingToEmit() && numUncommittedOffsets < maxUncommittedOffsets, it's always FALSE after reaching threshold, as numUncommittedOffsets is creasing and never reset on 'At-Most-Once' mode.
What's the solution?
I change the condition to !waitingToEmit() && (numUncommittedOffsets < maxUncommittedOffsets || consumerAutoCommitMode), that return TRUE with AutoCommitMode regarding of UnCommittedOffset, see the comments inline.
Also, it's not required to track emitted(msgId) and numUncommittedOffsets with AutoCommitMode .
Summary: fix At-Most-Once issue in KafkaSpout (was: KafkaSpout is blocked in AutoCommitMode)
> fix At-Most-Once issue in KafkaSpout
> ------------------------------------
>
> Key: STORM-2340
> URL: https://issues.apache.org/jira/browse/STORM-2340
> Project: Apache Storm
> Issue Type: Improvement
> Components: storm-kafka-client
> Reporter: Xu Mingmin
> Time Spent: 10m
> Remaining Estimate: 0h
>
> What's the issue?
> When Storm topology is run on 'At-Most-Once' mode, with ack executor=0, KafkaSpout cannot emit records after some time.
> What's the cause?
> Function poll() controls whether it need to pull more data from Kafka cluster. With the condition !waitingToEmit() && numUncommittedOffsets < maxUncommittedOffsets, it's always FALSE after reaching threshold, as numUncommittedOffsets is creasing and never reset on 'At-Most-Once' mode.
> What's the solution?
> I change the condition to !waitingToEmit() && (numUncommittedOffsets < maxUncommittedOffsets || consumerAutoCommitMode), that return TRUE with AutoCommitMode regarding of UnCommittedOffset, see the comments inline.
> Also, it's not required to track emitted(msgId) and numUncommittedOffsets with AutoCommitMode .
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