[HBASE-10017] HRegionPartitioner, rows directed to last partition are wrongly mapped.

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Abandoned
• Affects Version/s: 0.94.6
• Component/s: mapreduce
• Assignee: Unassigned
• Reporter: Roman Nikitchenko
• Created: 21/Nov/13 14:57
• Updated: 17/Jun/22 15:27
• Resolved: 17/Jun/22 15:27

Description

Inside HRegionPartitioner class there is getPartition() method which should map first numPartitions regions to appropriate partitions 1:1. But based on condition last region is hashed which could lead to last reducer not having any data. This is considered serious issue.

I reproduced this only starting from 16 regions per table. Original defect was found in 0.94.6 but at least today's trunk and 0.91 branch head have the same HRegionPartitioner code in this part which means the same issue.