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https://issues.apache.org/jira/browse/FLINK-34266?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17811913#comment-17811913
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Gyula Fora commented on FLINK-34266:
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cc [~mxm]
> Output ratios should be computed over the whole metric window instead of
> averaged
> ---------------------------------------------------------------------------------
>
> Key: FLINK-34266
> URL: https://issues.apache.org/jira/browse/FLINK-34266
> Project: Flink
> Issue Type: Improvement
> Components: Autoscaler
> Reporter: Gyula Fora
> Priority: Critical
>
> Currently Output ratios are computed during metric collection based on the
> current in/out metrics an stored as part of the collected metrics.
> During evaluation the output ratios previously computed are then averaged
> together in the metric window. This however leads to incorrect computation
> due to the nature of the computation and averaging.
> Example:
> Let's look at a window operator that simply sorts and re-emits events in
> windows. During the window collection phase, output ratio will be computed
> and stored as 0. During the window computation the output ratio will be
> last_input_rate / window_size. Depending on the last input rate observation
> this can be off when averaged into any direction.
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