[HIVE-20873] Use Murmur hash for VectorHashKeyWrapperTwoLong to reduce hash collision

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-alpha-1
• Labels: pull-request-available
• Assignee: Teddy Choi Assign to me
• Reporter: Teddy Choi
• Created: 06/Nov/18 17:59
• Updated: 17/Nov/22 08:54
• Resolved: 27/Nov/18 11:09

Description

VectorHashKeyWrapperTwoLong is implemented with few bit shift operators and XOR operators for short computation time, but more hash collision. Group by operations become very slow on large data sets. It needs Murmur hash or a better hash function for less hash collision.

Issue Links

• links to: GitHub Pull Request #485
• links to: GitHub Pull Request #485

Sub-Tasks

• Benchmark XXhash for 64 bit hashing function instead of Murmum hash: Open