Fix concat for sliced ListArrays
#7037
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alamb
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ListArraysconcat for sliced ListArrays
arrow-select/src/concat.rs
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| let offsets = x.offsets(); | ||
| let start_offset = offsets[0].as_usize(); | ||
| let end_offset = offsets[offsets.len() - 1].as_usize(); | ||
| x.values().slice(start_offset, end_offset - start_offset) |
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The issue is that the values of sliced ListArrays do not necessairly start at zero
For the test in this PR, the offsets are:
concat_lists offsets: OffsetBuffer(ScalarBuffer([5, 5, 5]))
concat_lists offsets: OffsetBuffer(ScalarBuffer([0, 0, 3, 4]))
| .collect::<Vec<_>>(); | ||
| // If any of the lists have slices, we need to slice the values | ||
| // to ensure that the offsets are correct | ||
| let mut sliced_values; |
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While I was futzing with this, I figured I would avoid slice on the values unless it was necessary.
I can make this code simpler if we always slice but that will always make an ArrayRef clone
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Is slice really expensive? Isn't it zero copy as the actual values (everything that is using Buffer) are behind arc?
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I don't think they are very expensive (they are several Arc::clone)
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Given this isn't a hot loop, it is invoked once per input array, I suspect the overheads of slice would likely be irrelevant, but this is also fine
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| Some(vec![Some(10)]), | ||
| ]; | ||
| let list1_array = ListArray::from_iter_primitive::<Int64Type, _, _>(list1.clone()); | ||
| let list1_array = list1_array.slice(1, 2); |
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I would add assertion here that the offsets really don't start from 0 to make sure we actually cover that case
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Good idea. Thank you for the suggestion. done in e22760e 👍
| .collect::<Vec<_>>(); | ||
| // If any of the lists have slices, we need to slice the values | ||
| // to ensure that the offsets are correct | ||
| let mut sliced_values; |
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Given this isn't a hot loop, it is invoked once per input array, I suspect the overheads of slice would likely be irrelevant, but this is also fine
Co-authored-by: Raz Luvaton <[email protected]>
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I plan to merge this tomorrow morning and make a 54.1.0 release candidate |
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Merging and will make a release candidate shortly |
Which issue does this PR close?
ListArrays is broken #7034Rationale for this change
Fixes a regression introduced in
concatkernel will merge dictionary values for list of dictionaries #6893What changes are included in this PR?
I also tested that this fixes the issue I found downstream in
54.1.0datafusion#14328Are there any user-facing changes?
Fix a bug