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https://issues.apache.org/jira/browse/NUTCH-2328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15585585#comment-15585585
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Sebastian Nagel commented on NUTCH-2328:
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Thanks, [~arthur-evozon]. Good catch!
In which environment was the problem observed? E.g.,
- running Nutch via bin/crawl or via Nutch server ?
- in local / pseudo-distributed / fully distributed Hadoop environment ?
The variable {{count}} should not be static, that's definitely a problem when
running multiple Generator jobs from a long-running Nutch server in local mode
where all tasks are run in the same JVM.
The variable {{limit}} is a per-task limit (see how it's initialized in
{{setup(context)}}), comparing it with a global counter seems wrong, also
retrieving the counter in every call of the reduce function may be too
expensive. Why not make {{count}} an instance variable?
> 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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