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From "Pradeep Kamath (JIRA)" <j...@apache.org>
Subject [jira] Updated: (PIG-578) join ... outer, ... outer semantics are a no-ops, should produce corresponding null values
Date Thu, 03 Sep 2009 23:24:57 GMT

     [ https://issues.apache.org/jira/browse/PIG-578?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Pradeep Kamath updated PIG-578:
-------------------------------

    Attachment: PIG-578-2.patch

Addressed the javadoc warning and 4 of the findbugs. There will still be 1 findbugs relating
to uppercase methodname in Queryparser - this is because currently all methods in QueryParser
are in Upper case and I am just following the convention in that file. At some point we should
rename all filenames to be lowercase.

The two junit failures are because the hudson QA process is unable to get "javac" from path
for tests unrelated to this patch and hence are not an issue.

> join ... outer, ... outer semantics are a no-ops, should produce corresponding null values
> ------------------------------------------------------------------------------------------
>
>                 Key: PIG-578
>                 URL: https://issues.apache.org/jira/browse/PIG-578
>             Project: Pig
>          Issue Type: Improvement
>          Components: impl
>    Affects Versions: 0.2.0
>            Reporter: David Ciemiewicz
>            Assignee: Pradeep Kamath
>             Fix For: 0.4.0
>
>         Attachments: PIG-578-2.patch, PIG-578.patch
>
>
> Currently using the "OUTER" modifier in the JOIN statement is a no-op.  The resuls of
JOIN are always an INNER join.  Now that the Pig types branch supports null values proper,
the semantics of JOIN ... OUTER, ... OUTER should be corrected to do proper outer joins and
populating the corresponding empty values with nulls.
> Here's the example:
> A = load 'a.txt' using PigStorage() as ( comment, value );
> B = load 'b.txt' using PigStorage() as ( comment, value );
> --
> -- OUTER clause is ignored in JOIN statement and does not populat tuple with
> -- null values as it should. Otherwise OUTER is a meaningless no-op modifier.
> --
> ABOuterJoin = join A by ( comment ) outer, B by ( comment ) outer;
> describe ABOuterJoin;
> dump ABOuterJoin;
> The file a contains:
> a-only  1
> ab-both 2
> The file b contains:
> ab-both 2
> b-only  3
> When you execute the script today, the dump results are:
> (ab-both,2,ab-both,2)
> The expected dump results should be:
> (a-only,1,,)
> (ab-both,2,ab-both,2)
> (,,b-only,3)

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