[jira] [Closed] (NUTCH-1366) speed up indexing by eliminating the indexreducer

["Ferdy Galema (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/NUTCH-1366?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ferdy Galema closed NUTCH-1366.
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    Resolution: Fixed

committed
                
> speed up indexing by eliminating the indexreducer
> -------------------------------------------------
>
>                 Key: NUTCH-1366
>                 URL: https://issues.apache.org/jira/browse/NUTCH-1366
>             Project: Nutch
>          Issue Type: Improvement
>          Components: indexer
>            Reporter: Ferdy Galema
>             Fix For: nutchgora
>
>         Attachments: NUTCH-1366.patch
>
>
> Currently the indexer in Nutchgora consists of both mappers and reduces. But the reduce code does not actually iterate over any (grouped/sorted) values. It simply indexes individual key/value (String/Webpage) pairs. Therefore by moving this indexing code to the mapper we can eliminate the reduce step therefore making the indexing job much faster. (No more unnecessary spilling to disk/network and no cpu wasted to sorting).
> Note this is not (directly) applicable to trunk because trunk uses a quite different approach. Different types of input are combined to a single value in the reducer. Although I think it is possible to implement a similar optimization I am not sure how to do this. So if anyone wants this for trunk too feel free to implement a similar patch.

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