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From Jason Kania <>
Subject Re: Question About Emitted, Transferred and Acked Bolts
Date Mon, 23 Feb 2015 19:14:26 GMT
I have two comments to add:
1) Is there any JIRA for invalid metrics values? I did not see one. I am running with bolts
having breakpoints and long before my bolts are every entered, the metrics indicate that these
bolts already have more than 100 emits. I have thought to raise a JIRA on this but I am not
sure what I would add for details. Would some specific debug output aid in resolving this?

2) For acks, is there any possibility of adding tracking for acks that happen after a timeout?
I can step into my bolt each time it is called and confirm that it is acking each request,
yet the acks do not match the emits (which should have a 1 to 1 ratio). I am guessing that
this is because the ack happened too late or it might be incorrect metrics total.

I use the STORM UI for processing tracking.

      From: Nathan Leung <>
 To: user <> 
 Sent: Monday, February 23, 2015 11:56 AM
 Subject: Re: Question About Emitted, Transferred and Acked Bolts
executed = # of times you called executedacked = # of executed tuples that you acked; ideally
this will match executedemitted = # of tuples that you emitted; if you call emit more than
once per execute call this can be higher than execute counttransferred = # of tuples transferred
downstream; if you have 2 bolts subscribing to your bolt, then this count can be higher than

On Mon, Feb 23, 2015 at 11:35 AM, Rahul Reddy <> wrote:


Can you guys help me understand difference between emitted, transferred and acked tuples.

In my case every tuple emitted by ablog-filter-bolt will be processed by ablog-flatten-xml-bolt
which will then be written by ablog-hdfs-bolt to hdfs. Ideally all metrics for executed/acked
should match after tuples are emitted from ablog-filter-bolt . I'm not sure why there is so
much discrepancy in emitted/transferredacked tuple count between these bolts although it dosent
show any failed tuples.

Any ideas what I can check and how to interpret metrics correctly?


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