If you want the gauge to only represent recent activity then you will
need to use a timer of sorts to reset the gauge after N time (something
larger than the reporter interval) unless it was changed in the meantime
(e.g., by also recording a timestamp within SimpleGauge)
On 1/13/2021 9:33 AM, Manish G wrote:
This approach has an issue. Even for those periods when there is no
activity, still the latest gauge value is used for calculations and
this generates graphs which are not correct representation of the
situation.
On Tue, Jan 12, 2021 at 7:01 PM Manish G <manish.c.ghildi...@gmail.com
<mailto:manish.c.ghildi...@gmail.com>> wrote:
Prometheus provides avg_over_time for a range vector. That seems
to be better suited for this usecase.
On Tue, Jan 12, 2021 at 6:53 PM Chesnay Schepler
<ches...@apache.org <mailto:ches...@apache.org>> wrote:
The cumulative time probably isn't that useful to detect
changes in the behavior of the application.
On 1/12/2021 12:30 PM, Chesnay Schepler wrote:
I mean the difference itself, not cumulative.
On 1/12/2021 12:08 PM, Manish G wrote:
Can you elaborate the second approach more?
Currently I am exposing the difference itself. OR do you
mean the cumulative difference?ie I maintain a member
variable, say timeSoFar, and update it with time consumed by
each method call and then expose it. Something like this:
timeSoFar += timeConsumedByCurrentInvocation
this.simpleGaug.setValue( timeSoFar );
On Tue, Jan 12, 2021 at 4:24 PM Chesnay Schepler
<ches...@apache.org <mailto:ches...@apache.org>> wrote:
That approach will generally not work for jobs that run
for a long time, because it will be nigh impossible for
anomalies to affect the average. You want to look into
exponential moving averages.
Alternatively, just expose the diff as an absolute value
and calculate the average in prometheus.
On 1/12/2021 11:50 AM, Manish G wrote:
OK, got it.
So I would need to accumulate the time value over the
calls as well as number of times it is called...and
then calculate average(accumulated time/ number of
times called) and then set calculated value into gauge
as above.
On Tue, Jan 12, 2021 at 4:12 PM Chesnay Schepler
<ches...@apache.org <mailto:ches...@apache.org>> wrote:
A gauge just returns a value, and Flink exposes it
as is. As such you need to calculate the average
over time yourself, taking 2 time measurements
(before and after the processing of each).
On 1/12/2021 11:31 AM, Manish G wrote:
startTime is set at start of function:
long startTime = System.currentTimeMillis();
On Tue, Jan 12, 2021 at 3:59 PM Manish G
<manish.c.ghildi...@gmail.com
<mailto:manish.c.ghildi...@gmail.com>> wrote:
My code is:
|public class SimpleGauge<T> implements
Gauge<T> { private T mValue; @Override public
T getValue() { return mValue; } public void
setValue(T value){ mValue = value; } }|
And in flatmap function:
|float endTime = (System.currentTimeMillis() -
startTime) / 1000F;
this.simplegauge.setValue(endTime); |
|So does it mean when flink calls my getValue
function to accumulate the value, and not to
take it as snapshot? |
On Tue, Jan 12, 2021 at 3:53 PM Chesnay
Schepler <ches...@apache.org
<mailto:ches...@apache.org>> wrote:
Sure, that might work. Be aware though
that time measurements are,
compared to the logic within a function,
usually rather expensive and
may impact performance.
On 1/12/2021 10:57 AM, Manish G wrote:
> Hi All,
>
> I have implemented a flatmap function
and I want to collect metrics
> for average time for this function which
I plan to monitor via prometheus.
>
> What would be good approach for it? I
have added a gauge to the
> method(extending Gauge interface from
flink API). Would it work for my
> needs?
>
>
