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https://issues.apache.org/jira/browse/HIVE-7159?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gunther Hagleitner updated HIVE-7159:
-------------------------------------
Attachment: HIVE-7159.6.patch
More golden file updates in 6.
There seems to be a couple of issues though that are either wrong with this
patch or might be exposing problems with the original code:
a) subquery transformation doesn't generate the nullsafe array (already
addressed in patch)
b) join pushdown does not seem to correctly populate the nullsafe array
(size(join condns) != size(nullsafe))
c) Somehow this patch seems to change ptf/windowing tests results (actual query
results, not just explain)
[~rhbutani] any thoughts?
> For inner joins push a 'is not null predicate' to the join sources for every
> non nullSafe join condition
> --------------------------------------------------------------------------------------------------------
>
> Key: HIVE-7159
> URL: https://issues.apache.org/jira/browse/HIVE-7159
> Project: Hive
> Issue Type: Bug
> Reporter: Harish Butani
> Assignee: Harish Butani
> Attachments: HIVE-7159.1.patch, HIVE-7159.2.patch, HIVE-7159.3.patch,
> HIVE-7159.4.patch, HIVE-7159.5.patch, HIVE-7159.6.patch
>
>
> A join B on A.x = B.y
> can be transformed to
> (A where x is not null) join (B where y is not null) on A.x = B.y
> Apart from avoiding shuffling null keyed rows it also avoids issues with
> reduce-side skew when there are a lot of null values in the data.
> Thanks to [~gopalv] for the analysis and coming up with the solution.
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