You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@hive.apache.org by "Harish Butani (JIRA)" <ji...@apache.org> on 2014/05/31 19:41:01 UTC
[jira] [Created] (HIVE-7159) For inner joins push a 'is not null
predicate' to the join sources for every non nullSafe join condition
Harish Butani created HIVE-7159:
-----------------------------------
Summary: 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
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.
--
This message was sent by Atlassian JIRA
(v6.2#6252)