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From "Gabriel Reid (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CRUNCH-278) Improvements to MapsideJoin code
Date Fri, 11 Oct 2013 08:22:42 GMT

    [ https://issues.apache.org/jira/browse/CRUNCH-278?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13792451#comment-13792451
] 

Gabriel Reid commented on CRUNCH-278:
-------------------------------------

Ok, got it. 

The biggest trade-off I see with using ReadableSourceBundle vs something that implements PCollection
for the in-memory thing is that using ReadableSourceBundle will prevent the issue with invalid
write calls, but also prevent using library functions like the stuff in o.a.c.lib.*, such
as Distinct. 

I'm sure that there are some ways we could get around the Pipeline#write issue, but there's
a good chance that some/all of them would come at the cost of being confusing for users.

> Improvements to MapsideJoin code
> --------------------------------
>
>                 Key: CRUNCH-278
>                 URL: https://issues.apache.org/jira/browse/CRUNCH-278
>             Project: Crunch
>          Issue Type: Bug
>          Components: Core, MapReduce Patterns
>            Reporter: Josh Wills
>            Assignee: Josh Wills
>         Attachments: CRUNCH-278.patch
>
>
> The fact that we have special-case code in the MapsideJoinStrategy for the in-memory
and MR-based Pipeline instances has always bugged me, so I set out to eliminate the distinction
between the two impls by creating a new interface, ReadableSourceBundle<T>, that encapsulates
the MR and in-memory specific logic for doing mapside joins in order to remove the special-case
code in MapsideJoinStrategy and hopefully make other implementations that use our mapside-join
patterns much easier to test.



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