[KYLIN-1677] Distribute source data by certain columns when creating flat table

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: v1.5.3
• Component/s: Job Engine
• Assignee: Shao Feng Shi
• Reporter: Shao Feng Shi
• Created: 11/May/16 07:06
• Updated: 28/Jul/16 06:48
• Resolved: 05/Jul/16 09:24

Description

Inspired by KYLIN-1656, Kylin can distribute the source data by certain columns when creating the flat hive table; Then the data assigned to a mapper will have more similarity, more aggregation can happen at mapper side, and then less shuffle and reduce is needed.

Columns can be used for the distribution includes: ultra high cardinality column, mandantory column, partition date/time column, etc.

Issue Links

• relates to: KYLIN-1656 Improve performance of MRv2 engine by making each mapper handles a configured number of records