Details
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Bug
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Status: Resolved
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Major
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Resolution: Fixed
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None
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None
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None
Description
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.
Attachments
Attachments
Issue Links
- is depended upon by
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HIVE-7148 Use murmur hash to create bucketed tables
- Open
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HIVE-7158 Use Tez auto-parallelism in Hive
- Closed
- is related to
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HIVE-7074 The reducer parallelism should be a prime number for better stride protection
- Resolved
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HIVE-6924 MapJoinKeyBytes::hashCode() should use Murmur hash
- Closed
- supercedes
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HIVE-7074 The reducer parallelism should be a prime number for better stride protection
- Resolved
- links to