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https://issues.apache.org/jira/browse/HIVE-7121?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14013292#comment-14013292
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Gunther Hagleitner commented on HIVE-7121:
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Patch looks good. This doesn't affect bucketed tables, but we should still open
another jira to handle that case too.
+1 assuming tests pass.
> Use murmur hash to distribute HiveKey
> -------------------------------------
>
> Key: HIVE-7121
> URL: https://issues.apache.org/jira/browse/HIVE-7121
> Project: Hive
> Issue Type: Bug
> Components: Query Processor
> Reporter: Gopal V
> Assignee: Gopal V
> Attachments: HIVE-7121.1.patch, HIVE-7121.2.patch, HIVE-7121.3.patch,
> HIVE-7121.WIP.patch
>
>
> The current hashCode implementation produces poor parallelism when dealing
> with single integers or doubles.
> And for partitioned inserts into a 1 bucket table, there is a significant
> hotspot on Reducer #31.
> Removing the magic number 31 and using a more normal hash algorithm would
> help fix these hotspots.
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