> On May 13, 2015, 11:50 p.m., Aditya Auradkar wrote:
> > clients/src/main/java/org/apache/kafka/common/metrics/stats/SampledStat.java,
> >  line 45
> > <https://reviews.apache.org/r/34170/diff/2/?file=958605#file958605line45>
> >
> >     I think this is a good catch.
> >     
> >     Just so I understand, this is adding new samples for blank intervals of 
> > time when record was not called. As an optimization, I think you should 
> > only add "MetricConfig.samples" number of samples. In the rare case, there 
> > is no activity for 10 mins (say), this will add 10sec*6*10 = 600 samples 
> > which will be purged immediately on the next record call.
> 
> Jay Kreps wrote:
>     This is a really good point. It is totally possible for a metric to track 
> activity on a topic that has no writes for a month, the first write would 
> then cause you to cycle through a month of samples. The logic around 
> correctly skipping these windows and calculating the correct window boundry 
> needs to be carefully worked out.

Actually maybe you can elaborate on why this is needed at all? In the current 
code if the current sample is complete we add a new sample. Your code adds lots 
of samples. But why do we need that? Isn't purging obsolete samples handled on 
measurement already? I think that is more elegant. You must see some issue 
there, maybe you can explain?


- Jay


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On May 13, 2015, 10:32 p.m., Dong Lin wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/34170/
> -----------------------------------------------------------
> 
> (Updated May 13, 2015, 10:32 p.m.)
> 
> 
> Review request for kafka.
> 
> 
> Bugs: KAFKA-2191
>     https://issues.apache.org/jira/browse/KAFKA-2191
> 
> 
> Repository: kafka
> 
> 
> Description
> -------
> 
> KAFKA-2191; Measured rate should not be infinite
> 
> 
> Diffs
> -----
> 
>   clients/src/main/java/org/apache/kafka/common/metrics/stats/Rate.java 
> 98429da34418f7f1deba1b5e44e2e6025212edb3 
>   
> clients/src/main/java/org/apache/kafka/common/metrics/stats/SampledStat.java 
> b341b7daaa10204906d78b812fb05fd27bc69373 
> 
> Diff: https://reviews.apache.org/r/34170/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Dong Lin
> 
>

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