delta-io/delta

[Kernel][Defaults] Support `COALESCE` for all data types in the `DefaultExpressionHandler`

Open

#2,416 opened on Dec 28, 2023

View on GitHub
 (2 comments) (0 reactions) (0 assignees)Scala (8,807 stars) (2,100 forks)batch import
enhancementgood first issuekernel

Description

Feature request

Which Delta project/connector is this regarding?

  • Spark
  • Standalone
  • Flink
  • Kernel
  • Other (fill in here)

Overview

#2415 adds support for COALESCE for boolean type expressions. We should support all data types.

Further details

#2415 already adds the needed changes. To support more data types we just need to add tests and remove the check that allows only boolean type in DefaultExpressionEvaluator.

Contributor guide

Tech stack
scala
Domain
database
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Familiarity with Delta KernelUnderstanding of PR #2415
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Examine the changes in PR #2415 that added COALESCE support for boolean types. Identify the check in DefaultExpressionEvaluator that restricts COALESCE to boolean types. Add tests for other data types (e.g., integer, string) and remove the boolean only check. Refer to the existing test patterns in the Kernel module.
[Kernel][Defaults] Support `COALESCE` for all data types in the `DefaultExpressionHandler` · delta-io/delta#2416 | Good First Issue