trinodb/trino

Return execution metrics while running the `OPTIMIZE` command in Delta Lake

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#28,999 opened on Apr 6, 2026

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 (3 comments) (1 reaction) (0 assignees)Java (2,678 forks)batch import
delta-lakegood first issue

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Description

We can return metrics such as rewritten data files, removed deletion vectors, added data files in Delta Lake OPTIMIZE procedure.

https://github.com/trinodb/trino/blob/11bf3c068037352ed9ee6fb8293154c7b9416452/plugin/trino-delta-lake/src/main/java/io/trino/plugin/deltalake/DeltaLakeMetadata.java#L2940-L2950

Contributor guide

Research direction
Study the OPTIMIZE method in DeltaLakeMetadata.java and the referenced PR #28992 to implement returning execution metrics.
Tech stack
java
Domain
backend
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.
1-2 days
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
GitJava
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65