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From "Roger Dunk (JIRA)" <j...@apache.org>
Subject [jira] Commented: (NUTCH-721) Fetcher2 Slow
Date Fri, 03 Apr 2009 08:53:12 GMT

    [ https://issues.apache.org/jira/browse/NUTCH-721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12695298#action_12695298
] 

Roger Dunk commented on NUTCH-721:
----------------------------------

I did a -"topN 5000", so only a subset of the attached, but still only 1 URL per host. The
following is with 20 threads and also no parsing.

[root@server1 trunk]# time bin/nutch org.apache.nutch.fetcher.Fetcher newcrawl/segments/20090402130655
-threads 20 -noParsing

[...]

Aborting with 20 hung threads.
Fetcher: done

real    60m14.926s
user    0m38.671s
sys     0m6.134s

> Fetcher2 Slow
> -------------
>
>                 Key: NUTCH-721
>                 URL: https://issues.apache.org/jira/browse/NUTCH-721
>             Project: Nutch
>          Issue Type: Bug
>          Components: fetcher
>    Affects Versions: 1.0.0
>         Environment: Fedora Core r6, Kernel 2.6.22-14,  jdk1.6.0_12
>            Reporter: Roger Dunk
>         Attachments: crawl_generate.tar.gz, nutch-site.xml
>
>
> Fetcher2 fetches far more slowly than Fetcher1.
> Config options:
> fetcher.threads.fetch = 80
> fetcher.threads.per.host = 80
> fetcher.server.delay = 0
> generate.max.per.host = 1
> With a queue size of ~40,000, the result is:
> activeThreads=80, spinWaiting=79, fetchQueues.totalSize=0
> with maybe a download of 1 page per second.
> Runing with -noParse makes little difference.
> CPU load average is around 0.2. With Fetcher1 CPU load is around 2.0 - 3.0
> Hosts already cached by local caching NS appear to download quickly upon a re-fetch,
so possible issue relating to NS lookups, however all things being equal Fetcher1 runs fast
without pre-caching hosts.

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