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https://issues.apache.org/jira/browse/FLINK-9998?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17336604#comment-17336604
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Flink Jira Bot commented on FLINK-9998:
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This issue was labeled "stale-major" 7 ago and has not received any updates so
it is being deprioritized. If this ticket is actually Major, please raise the
priority and ask a committer to assign you the issue or revive the public
discussion.
> FlinkKafkaConsumer produces lag -Inf when the pipeline lags
> -----------------------------------------------------------
>
> Key: FLINK-9998
> URL: https://issues.apache.org/jira/browse/FLINK-9998
> Project: Flink
> Issue Type: Bug
> Components: Connectors / Kafka
> Affects Versions: 1.4.0
> Reporter: Julio Biason
> Priority: Major
> Labels: stale-major
>
> I reported this in the list, but now I have enough information to understand
> what's going on.
> Sometimes, the kafkaConsumer will report a lag
> (flink_taskmanager_job_task_operator_KafkaConsumer_records_lag_max) of -Inf.
> The problem seems to related to the capture time.
> If the pipeline (defines with EXACTLY_ONCE) starts lagging at some point,
> there won't be enough information in a certain period and the reported lag
> becomes -Inf.
> Example: We had an external SQL Sink, pointing to a RDS source, but with a
> cluster outside AWS. This produced a flush time of about 2 minutes for 500
> records (captured 'cause we added a metric around `upload.executeBatch()`
> inside JDBCOutputFormat); although absurd (which is another problem), during
> this time, the metric would report `-Inf` and return the a proper value once
> the stream finished.
> So it seems the lag, instead of being a captured value and kept in memory,
> it's calculated from time to time instead of being kept in memory and updated
> from time to time (just because there wasn't any record processed in a
> certain period, it doesn't mean the lag went down).
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