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https://issues.apache.org/jira/browse/AMBARI-16946?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15306267#comment-15306267
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Sriharsha Chintalapani commented on AMBARI-16946:
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[~kabhwan] no lets create the patch against trunk
> Storm Metrics Sink has high chance to discard some datapoints
> -------------------------------------------------------------
>
> Key: AMBARI-16946
> URL: https://issues.apache.org/jira/browse/AMBARI-16946
> Project: Ambari
> Issue Type: Bug
> Components: ambari-metrics
> Affects Versions: 2.4.0
> Reporter: Jungtaek Lim
> Attachments: AMBARI-16946.patch
>
>
> There's a mismatch between TimelineMetricsCache and Storm metrics unit, while
> TimelineMetricsCache considers "metric name + timestamp" to be unique but
> Storm is not.
> For example, assume that bolt B has task T1, T2 and B has registered metrics
> M1. It's possible for metrics sink to receive (T1, M1) and (T2, M1) with same
> timestamp TS1 (in TaskInfo, not current time), and received later will be
> discarded from TimelineMetricsCache.
> If we want to have unique metric point of Storm, we should use "topology name
> + component name + task id + metric name" to metric name so that "metric name
> + timestamp" will be unique.
> There're other issues I would like to address, too.
> - Currently, hostname is written to hostname of the machine which runs
> metrics sink. Since TaskInfo has hostname of the machine which runs task,
> we're better to use this.
> - Unit of timestamp of TaskInfo is second, while Storm Metrics Sink uses this
> as millisecond, resulting in timestamp flaw, and malfunction of cache
> eviction. It should be multiplied by 1000.
> - 'component name' is not unique across the cluster, so it's not fit for app
> id. 'topology name' is unique so proper value of app id is topology name.
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