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https://issues.apache.org/jira/browse/FLINK-9789?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16538582#comment-16538582
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ASF GitHub Bot commented on FLINK-9789:
---------------------------------------
Github user aljoscha commented on a diff in the pull request:
https://github.com/apache/flink/pull/6292#discussion_r201340299
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/tasks/OneInputStreamTask.java
---
@@ -93,7 +93,7 @@ public void init() throws Exception {
inputWatermarkGauge);
}
headOperator.getMetricGroup().gauge(MetricNames.IO_CURRENT_INPUT_WATERMARK,
this.inputWatermarkGauge);
-
getEnvironment().getMetricGroup().gauge(MetricNames.IO_CURRENT_INPUT_WATERMARK,
this.inputWatermarkGauge);
+
getEnvironment().getMetricGroup().gauge(MetricNames.IO_CURRENT_INPUT_WATERMARK,
this.inputWatermarkGauge::getValue);
--- End diff --
maybe document that we create a wrapping metric because registered metrics
objects have to be unique
> 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
> Labels: pull-request-available
> 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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