[SPARK-18000] Aggregation function for computing bins (distinct value, count) pairs for equi-width histograms

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.1.0
• Component/s: SQL
• Assignee: Unassigned
• Reporter: Zhenhua Wang
• Created: 19/Oct/16 02:53
• Updated: 18/Nov/16 22:26
• Resolved: 18/Nov/16 22:26

Description

This function computes the count for each distinct non-null value of a column.
It returns:
1. null if the table is empty or all values of the column are null.
2. (distinct non-null value, frequency) pairs if the number of distinct non-null values is less than or equal to the specified threshold.
3. an empty result if the number of distinct non-null values exceeds that threshold.

Issue Links

• is part of: SPARK-17074 generate equi-height histogram for column
• links to: [Github] Pull Request #15637 (wzhfy)