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https://issues.apache.org/jira/browse/KAFKA-13936?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17558339#comment-17558339
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Prashanth Joseph Babu commented on KAFKA-13936:
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[~mjsax] I looked into the doc section and thought of adding a NOTE under `The 
maximum lag in terms of number of records for any partition in this window` . 
However if i look for this text in the repository , I see it in the file 
FetcherMetricsRegistry.java . Is this where the change is supposed to happen ( 
and it gets auto generated to html somewhere else ) ? . I don't see a html file 
or any markdown document which has this text.

> Invalid consumer lag when monitoring from a kafka streams application
> ---------------------------------------------------------------------
>
>                 Key: KAFKA-13936
>                 URL: https://issues.apache.org/jira/browse/KAFKA-13936
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>            Reporter: Prashanth Joseph Babu
>            Priority: Major
>
> I have a kafka streams application and I'm trying to monitor the consumer lag 
> via stream metrics.
> Here's some code snippet
> {code:java}
> metrics = streams.metrics();
>             lag = 0;
>             for (Metric m : metrics.values()) {
>                 tags = m.metricName().tags();
>                 if ( m.metricName().name().equals(MONITOR_CONSUMER_LAG) && 
> tags.containsKey(MONTOR_TAG_TOPIC) && 
>                     tags.get(MONTOR_TAG_TOPIC).equals(inputTopic) ) {
>                     partitionLag = 
> Float.valueOf(m.metricValue().toString()).floatValue();
>                     if ( !partitionLag.isNaN() ) {
>                         lag += partitionLag;
>                     }
>                 }
>             }
> {code}
> Here MONITOR_CONSUMER_LAG is {{{}records-lag-max{}}}.
> However these numbers dont match with the consumer lag we see in the kafka UI 
> . is records-lag-max the right metric to track for a kafka streams 
> application when the objective is to get consumer lag?



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