Hi Felipe,

I checked the code path, and the metric of outPoolUsage is under the following layer: TaskMetricGroup -> TaskIOMetricGroup -> "buffers" group -> "outPoolUsage".
It seems that you missed the `TaskIOMetricGroup` from below samples. You can get it from TaskMetricGroup.

Hope it solve your problem.

Best,
Zhijiang

------------------------------------------------------------------
From:Felipe Gutierrez <felipe.o.gutierrez@gmail.com>
Send Time:2020 Mar. 17 (Tue.) 17:50
To:user <user@flink.apache.org>
Subject:Re: How do I get the outPoolUsage value inside my own stream operator?

Hi,

just for the record. I am collecting the values of outPoolUsage using
the piece of code below inside my stream operator

OperatorMetricGroup operatorMetricGroup = (OperatorMetricGroup)
this.getMetricGroup();
TaskMetricGroup taskMetricGroup = operatorMetricGroup.parent();
MetricGroup metricGroup = taskMetricGroup.getGroup("buffers");
Gauge<Float> gauge = (Gauge<Float>) metricGroup.getMetric("outPoolUsage");
if (gauge != null && gauge.getValue() != null) {
   float outPoolUsage = gauge.getValue().floatValue();
   this.outPoolUsageHistogram.update((long) (outPoolUsage * 100));
}


--
-- Felipe Gutierrez
-- skype: felipe.o.gutierrez
-- https://felipeogutierrez.blogspot.com

On Mon, Mar 16, 2020 at 5:17 PM Felipe Gutierrez
<felipe.o.gutierrez@gmail.com> wrote:
>
> Hi community,
>
> I have built my own operator (not a UDF) and I want to collect the
> metrics of "outPoolUsage" inside it. How do I do it assuming that I
> have to do some modifications in the source code?
>
> I know that the Gouge comes from
> flink-runtime/org.apache.flink.runtime.io.network.metrics.OutputBufferPoolUsageGauge.java.
> Inside of my operator MyAbstractUdfStreamOperator I can get the
> "MetricGroup metricGroup = this.getMetricGroup()".
> Then I implemented the "Gauge<Float> gauge = (Gauge<Float>)
> metricGroup.getMetric("outPoolUsage");" but it returns null all the
> time. Even when I click on the Backpressure UI Interface.
>
> Thanks,
> Felipe
> --
> -- Felipe Gutierrez
> -- skype: felipe.o.gutierrez
> -- https://felipeogutierrez.blogspot.com