[HIVE-16274] Support tuning of NDV of columns using lower/upper bounds

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.1.0
• Fix Version/s: 2.3.0
• Labels: TODOC2.3
• Assignee: Pengcheng Xiong
• Reporter: Pengcheng Xiong
• Created: 21/Mar/17 22:00
• Updated: 26/Mar/17 07:53
• Resolved: 26/Mar/17 00:29

Description

For partitioned tables, the distinct value (nDV) estimate for a column is by default set to the largest nDV value in any of the partitions being considered, which is a lower bound on the nDV estimate.
This provides a config setting to allow the estimate to a specified fraction (0.0 - 1.0) of the higher bound on the nDV estimate (the sum of all the nDVs in all partitions).

Issue Links

• links to: RB