Field pruning in nested struct scan#7327
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brancz wants to merge 2 commits into
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connortsui20
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Apr 7, 2026
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| let can_fast_path = match target_fields { | ||
| None => true, | ||
| Some(fields) => fields.len() >= n_struct_fields, | ||
| }; | ||
| if can_fast_path { |
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you can use is_none_or here
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This PR has been marked as stale because it has been open for 14 days with no activity. Please comment or remove the stale label if you wish to keep it active, otherwise it will be closed in 7 days |
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This PR was closed because it has been inactive for 7 days since being marked as stale. |
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Summary
I'm trying to have scans read only a subset of a nested struct. It's of the shape:
List<Struct<a: Utf8, b: Int64>, so I can't use regular projections in DataFusion, since those only support indices. This is my best attempt, combined with an optimizer rule that modifies the table schema to the subset under certain circumstances.Testing
Added a unit test that fails without the second commit.
Notes
Happy to think through other approaches to this, this was just the first thing that I came up with.