[IMPALA-10281] Implement count(distinct) function (DataSketches/CPC)

• Type: Epic
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Component/s: Backend
• Epic Name: DataSketches CPC support
• Epic Color: ghx-label-10
• Assignee: Fucun Chu
• Reporter: Fucun Chu
• Created: 24/Oct/20 01:47
• Updated: 12/Jul/21 01:51

Description

Implement the count(distinct) function from the DataSketches library for CPC in C++.

General info about the sketch:
http://datasketches.apache.org/docs/CPC/CPC.html

C++ implementation to wrap:
https://github.com/apache/incubator-datasketches-cpp/tree/master/cpc