apache/pinot

Multiple argument support for DISTINCTCOUNTHLL/DISTINCTCOUNTTHETASKETCH

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#8,225 opened on Feb 18, 2022

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help wanted

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Description

Currently pinot only supports a single argument for distinct count hll and thetasketch functions. For some use cases like ours where we needed distinct count by two columns and id and a date it is very useful.

https://docs.pinot.apache.org/users/user-guide-query/how-to-handle-unique-counting

Contributor guide

Research direction
Investigate how Pinot implements DISTINCTCOUNTHLL and DISTINCTCOUNTTHETASKETCH aggregation functions. Look at the source code for these functions, identify the signature and single argument handling. Then, design a modification to accept multiple arguments by either concatenating columns or using composite keys. Start by finding the relevant files in the Pinot query engine.
Tech stack
java
Domain
database
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Java
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70