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From "Ferdy Galema (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (NUTCH-1457) Nutch2 Refactor the update process so that fetched items are only processed once
Date Thu, 08 Nov 2012 22:30:12 GMT

    [ https://issues.apache.org/jira/browse/NUTCH-1457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13493565#comment-13493565
] 

Ferdy Galema commented on NUTCH-1457:
-------------------------------------

There is a limited description of the Nutch2 DbUpdater here:
http://wiki.apache.org/nutch/Nutch2Crawling#DbUpdate

Basically all outlinks of the table are needed (they are outputted in the Mapper), so that
they will be available as inlinks in the Reducer. They are needed to correctly update the
Score for each row. This may or may not be important in some cases, but for a correct calculation
of Score all rows+outlinks are needed.

My suggestion for this issue is to move some of the processing of the DbUpdater job to the
Fetcher. Namely the updating of the fetchstatus and fetchtime. Then it is possible to run
the DpUpdater job many times without pushing fetchtime far into the future. Slighly related,
there should be an extra field to distinct between "when was this item fetched" and "when
should it be fetched". Now both this information is stored in the single field "fetchtime".
                
> Nutch2 Refactor the update process so that fetched items are only processed once
> --------------------------------------------------------------------------------
>
>                 Key: NUTCH-1457
>                 URL: https://issues.apache.org/jira/browse/NUTCH-1457
>             Project: Nutch
>          Issue Type: Improvement
>            Reporter: Ferdy Galema
>


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