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https://issues.apache.org/jira/browse/STORM-2913?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stig Rohde Døssing reassigned STORM-2913:
-----------------------------------------
Assignee: Stig Rohde Døssing
> STORM-2844 made autocommit and at-most-once storm-kafka-client spouts log
> warnings on every emit
> ------------------------------------------------------------------------------------------------
>
> Key: STORM-2913
> URL: https://issues.apache.org/jira/browse/STORM-2913
> Project: Apache Storm
> Issue Type: Bug
> Components: storm-kafka-client
> Affects Versions: 2.0.0, 1.2.0
> Reporter: Stig Rohde Døssing
> Assignee: Stig Rohde Døssing
> Priority: Critical
>
> The mechanism added in https://issues.apache.org/jira/browse/STORM-2844 to
> allow us to check whether a committed offset was committed by the currently
> running topology requires that we commit some metadata along with the offset.
> We are using this metadata for two things: Only applying the
> FirstPollOffsetStrategy when the topology is deployed, rather than when the
> worker is restarted, and an (IMO fairly unimportant) runtime check that the
> spout offset tracking is not in a bad state.
> Autocommit spouts don't include this metadata, and we also don't include it
> when committing offsets in at-most-once mode. We can fix at-most-once by
> switching to committing a custom OffsetAndMetadata, rather than using the
> no-arg commitSync variant.
> I'm not sure what we should do to fix the autocommit case. There doesn't seem
> to be a way to include metadata in autocommits, so I don't think we can
> support this mechanism for autocommits.
> If we can't fix the autocommit case, I see two options for fixing this:
> * Make doSeek have the old behavior for autocommits only (i.e. apply the
> FirstPollOffsetStrategy on every worker restart), and keep the new behavior
> for at-least-once/at-most-once. I think this behavior could be a little
> confusing.
> * Revert doSeek to the old behavior in all cases, and throw out the runtime
> check that uses the metadata. This also isn't a great option, because the new
> seek behavior is more useful than restarting on every worker reboot.
> What do you think [~hmclouro]? I'm leaning toward the first option.
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