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https://issues.apache.org/jira/browse/FLINK-31977?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17719221#comment-17719221
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Gyula Fora edited comment on FLINK-31977 at 5/4/23 8:55 AM:
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The problem here is that you need to call the detection logic before you
trigger the event. The event should only be sent if ineffective scaling is
detected.
>From this perspective I think the current logic is correct
was (Author: gyfora):
The problem here is that you need to call the detection logic before you
trigger the event. The event should only be sent if ineffective scaling is
detected.
> If scaling.effectiveness.detection.enabled is false, the call to the
> detectIneffectiveScaleUp() function is unnecessary
> -----------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-31977
> URL: https://issues.apache.org/jira/browse/FLINK-31977
> Project: Flink
> Issue Type: Improvement
> Components: Autoscaler
> Affects Versions: 1.17.0
> Reporter: Tan Kim
> Priority: Minor
>
> The code below is a function to detect inefficient scaleups.
> It returns a result if the value of SCALING_EFFECTIVENESS_DETECTION_ENABLED
> (scaling.effectiveness.detection.enabled) is true after all the necessary
> computations for detection, but this is an unnecessary computation.
> {code:java}
> JobVertexScaler.java #175
> private boolean detectIneffectiveScaleUp(
> AbstractFlinkResource<?, ?> resource,
> JobVertexID vertex,
> Configuration conf,
> Map<ScalingMetric, EvaluatedScalingMetric> evaluatedMetrics,
> ScalingSummary lastSummary) {
> double lastProcRate =
> lastSummary.getMetrics().get(TRUE_PROCESSING_RATE).getAverage(); //
> 22569.315633422066
> double lastExpectedProcRate =
>
> lastSummary.getMetrics().get(EXPECTED_PROCESSING_RATE).getCurrent(); //
> 37340.0
> var currentProcRate =
> evaluatedMetrics.get(TRUE_PROCESSING_RATE).getAverage();
> // To judge the effectiveness of the scale up operation we compute how
> much of the expected
> // increase actually happened. For example if we expect a 100 increase in
> proc rate and only
> // got an increase of 10 we only accomplished 10% of the desired
> increase. If this number is
> // below the threshold, we mark the scaling ineffective.
> double expectedIncrease = lastExpectedProcRate - lastProcRate;
> double actualIncrease = currentProcRate - lastProcRate;
> boolean withinEffectiveThreshold =
> (actualIncrease / expectedIncrease)
> >=
> conf.get(AutoScalerOptions.SCALING_EFFECTIVENESS_THRESHOLD);
> if (withinEffectiveThreshold) {
> return false;
> }
> var message = String.format(INNEFFECTIVE_MESSAGE_FORMAT, vertex);
> eventRecorder.triggerEvent(
> resource,
> EventRecorder.Type.Normal,
> EventRecorder.Reason.IneffectiveScaling,
> EventRecorder.Component.Operator,
> message);
> if (conf.get(AutoScalerOptions.SCALING_EFFECTIVENESS_DETECTION_ENABLED)) {
> LOG.info(message);
> return true;
> } else {
> return false;
> }
> } {code}
> In the call to the detectIneffectiveScaleUp function, I would suggest
> checking SCALING_EFFECTIVENESS_DETECTION_ENABLED first, as follows.
> {code:java}
> JobVertexScaler.java #150
> if (currentParallelism == lastSummary.getNewParallelism() &&
> lastSummary.isScaledUp()) {
> if (scaledUp) {
>
> if(conf.get(AutoScalerOptions.SCALING_EFFECTIVENESS_DETECTION_ENABLED)) {
> return detectIneffectiveScaleUp(resource, vertex, conf,
> evaluatedMetrics, lastSummary);
> } else {
> return true;
> }
> } else {
> return detectImmediateScaleDownAfterScaleUp(vertex, conf,
> lastScalingTs);
> }
> }{code}
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