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https://issues.apache.org/jira/browse/FLINK-9789?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chesnay Schepler updated FLINK-9789:
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Description:
In FLINK-4812 we reworked the watermark metrics to be exposed for each operator.
In FLINK-9467 we made further modifications to also expose these metrics again
for tasks.
In both JIRAs we register a single metric multiple times, for example the input
watermark metric is registered for both the first operator in the task, and the
task itself.
Unfortunately, the metric system assumes metric objects to be unique, as can be
seen in virtually all reporter implementations as well as the
MetricQueryService.
As a result the watermark metrics override each other in the reporter, causing
only one to be reported, whichever was registered last.
was:
In FLINK-4812 we reworked the watermark metrics to be exposed for each operator.
In FLINK-9467 we made further modifications to also expose these metrics again
for tasks.
This works by re-using the input watermark gauge for the first operator in the
task chain, and the output watermark gauge for the last operator in the task
chain. This means that a single metric is registered multiple times.
Unfortunately, the metric system assumes metric objects to be unique, as can be
seen in virtually all reporter implementations as well as the
MetricQueryService.
As a result the watermark metrics override each other in the reporter, causing
only one to be reported, whichever was registered last.
FLINK-4812 was implemented for 1.5.1, so this would be a regression.
> Watermark metrics for an operator&task shadow each other
> --------------------------------------------------------
>
> Key: FLINK-9789
> URL: https://issues.apache.org/jira/browse/FLINK-9789
> Project: Flink
> Issue Type: Bug
> Components: Metrics
> Affects Versions: 1.5.0, 1.6.0
> Reporter: Chesnay Schepler
> Assignee: Chesnay Schepler
> Priority: Blocker
> Fix For: 1.5.2, 1.6.0
>
>
> In FLINK-4812 we reworked the watermark metrics to be exposed for each
> operator.
> In FLINK-9467 we made further modifications to also expose these metrics
> again for tasks.
> In both JIRAs we register a single metric multiple times, for example the
> input watermark metric is registered for both the first operator in the task,
> and the task itself.
> Unfortunately, the metric system assumes metric objects to be unique, as can
> be seen in virtually all reporter implementations as well as the
> MetricQueryService.
> As a result the watermark metrics override each other in the reporter,
> causing only one to be reported, whichever was registered last.
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