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https://issues.apache.org/jira/browse/NUTCH-2328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15588681#comment-15588681
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Arthur B commented on NUTCH-2328:
---------------------------------
Just making one last case for using a global job counter (with the caveat that
I am not that as familiar with the internals of Nutch as you):
* you are already incrementing this counter, so I am wondering how much more
overhead would be a read?; and
* what I noticed from tests that I ran is that you will actually will be losing
more than {{topN mod mapred.reduce.tasks}} due to reducer starvation (I think)
- roughly 60-70% of topN was achieved in my tests.
Just a thought.
> GeneratorJob does not generate anything on second run
> -----------------------------------------------------
>
> Key: NUTCH-2328
> URL: https://issues.apache.org/jira/browse/NUTCH-2328
> Project: Nutch
> Issue Type: Bug
> Components: generator
> Affects Versions: 2.2, 2.3, 2.2.1, 2.3.1
> Environment: Ubuntu 16.04 / Hadoop 2.7.1
> Reporter: Arthur B
> Labels: fails, generator, subsequent
> Fix For: 2.4
>
> Attachments: generator-issue-static-count.patch
>
> Original Estimate: 24h
> Remaining Estimate: 24h
>
> Given a topN parameter (ie 10) the GeneratorJob will fail to generate
> anything new on the subsequent runs within the same process space.
> To reproduce the issue submit the GeneratorJob twice one after another to the
> M/R framework. Second time will say it generated 0 URLs.
> This issue is due to the usage of the static count field
> (org.apache.nutch.crawl.GeneratorReducer#count) to determine if the topN
> value has been reached.
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