fields are never queried, why?

[github-actions]

fields are never queried, why?

https://github.com/apache/incubator-wayang/blob/3fa657bcc8c86198b9532aa06bf27964c3f771be/wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/rel/WayangTableScan.java#L35

import org.apache.calcite.rel.hint.RelHint;
import org.apache.calcite.schema.Table;
import org.apache.wayang.api.sql.calcite.convention.WayangConvention;

import java.util.List;

public class WayangTableScan extends TableScan implements WayangRel {

    //TODO: fields are never queried, why?
    private final int[] fields;

    public WayangTableScan(RelOptCluster cluster,

90ce836ef2aa36c822e4f7f1f1de6f543ddb4e50

[AjayBoddeda4]

Hi, I am Ajay Boddeda, a GSoC 2026 applicant working on the DataFrames API proposal for Wayang.
I came across this issue while studying the codebase. This is directly related to the select() operation I am planning to implement in the DataFrame API — where users specify which columns they need and only those should be queried.
My understanding is that the fields array in WayangTableScan stores the projected column indices, but these are never passed down to the actual query execution. This means even when a user does df.select('name', 'age'), all columns are fetched which is inefficient.
I would love to investigate this further and potentially contribute a fix. Could anyone guide me on where the fields array should be used in the execution flow?