perf: optimize array_remove for scalar needle #22390
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| Original file line number | Diff line number | Diff line change |
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@@ -18,16 +18,17 @@ | |
| //! [`ScalarUDFImpl`] definitions for array_remove, array_remove_n, array_remove_all functions. | ||
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| use crate::utils; | ||
| use arrow::array::{ | ||
| Array, ArrayRef, Capacities, GenericListArray, MutableArrayData, OffsetSizeTrait, | ||
| Scalar, cast::AsArray, make_array, | ||
| }; | ||
| use arrow::buffer::{NullBuffer, OffsetBuffer}; | ||
| use arrow::datatypes::{DataType, FieldRef}; | ||
| use datafusion_common::cast::as_int64_array; | ||
| use datafusion_common::utils::ListCoercion; | ||
| use datafusion_common::{ | ||
| Result, ScalarValue, exec_err, internal_err, utils::take_function_args, | ||
| }; | ||
| use datafusion_expr::{ | ||
| ArrayFunctionArgument, ArrayFunctionSignature, ColumnarValue, Documentation, | ||
| ScalarFunctionArgs, ScalarUDFImpl, Signature, TypeSignature, Volatility, | ||
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@@ -113,7 +114,21 @@ impl ScalarUDFImpl for ArrayRemove { | |
| } | ||
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| fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { | ||
| let [list_arg, element_arg] = take_function_args(self.name(), &args.args)?; | ||
| let num_rows = args.number_rows; | ||
| let list_array = list_arg.to_array(num_rows)?; | ||
| let arr_n = vec![1; num_rows]; | ||
| match element_arg { | ||
| ColumnarValue::Array(element_array) => { | ||
| let result = array_remove_internal(&list_array, element_array, &arr_n)?; | ||
| Ok(ColumnarValue::Array(result)) | ||
| } | ||
| ColumnarValue::Scalar(scalar_element) => { | ||
| let result = | ||
| remove_with_scalar_needle(&list_array, scalar_element, &arr_n)?; | ||
| Ok(ColumnarValue::Array(result)) | ||
| } | ||
| } | ||
| } | ||
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| fn aliases(&self) -> &[String] { | ||
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@@ -214,7 +229,23 @@ impl ScalarUDFImpl for ArrayRemoveN { | |
| } | ||
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| fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { | ||
| let [list_arg, element_arg, max_arg] = | ||
| take_function_args(self.name(), &args.args)?; | ||
| let num_rows = args.number_rows; | ||
| let list_array = list_arg.to_array(num_rows)?; | ||
| let max_array = max_arg.to_array(num_rows)?; | ||
| let arr_n = as_int64_array(&max_array)?.values().to_vec(); | ||
| match element_arg { | ||
| ColumnarValue::Array(element_array) => { | ||
| let result = array_remove_internal(&list_array, element_array, &arr_n)?; | ||
| Ok(ColumnarValue::Array(result)) | ||
| } | ||
| ColumnarValue::Scalar(scalar_element) => { | ||
| let result = | ||
| remove_with_scalar_needle(&list_array, scalar_element, &arr_n)?; | ||
| Ok(ColumnarValue::Array(result)) | ||
| } | ||
| } | ||
| } | ||
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| fn aliases(&self) -> &[String] { | ||
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@@ -304,7 +335,21 @@ impl ScalarUDFImpl for ArrayRemoveAll { | |
| } | ||
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| fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { | ||
| let [list_arg, element_arg] = take_function_args(self.name(), &args.args)?; | ||
| let num_rows = args.number_rows; | ||
| let list_array = list_arg.to_array(num_rows)?; | ||
| let arr_n = vec![i64::MAX; num_rows]; | ||
| match element_arg { | ||
| ColumnarValue::Array(element_array) => { | ||
| let result = array_remove_internal(&list_array, element_array, &arr_n)?; | ||
| Ok(ColumnarValue::Array(result)) | ||
| } | ||
| ColumnarValue::Scalar(scalar_element) => { | ||
| let result = | ||
| remove_with_scalar_needle(&list_array, scalar_element, &arr_n)?; | ||
| Ok(ColumnarValue::Array(result)) | ||
| } | ||
| } | ||
| } | ||
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| fn aliases(&self) -> &[String] { | ||
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@@ -316,27 +361,6 @@ impl ScalarUDFImpl for ArrayRemoveAll { | |
| } | ||
| } | ||
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| fn array_remove_internal( | ||
| array: &ArrayRef, | ||
| element_array: &ArrayRef, | ||
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@@ -357,6 +381,47 @@ fn array_remove_internal( | |
| } | ||
| } | ||
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| /// Dispatches scalar-needle array removal by list offset type. | ||
| /// | ||
| /// `needle` must be a length-1 array containing the scalar element to remove. | ||
| fn array_remove_dispatch_scalar( | ||
| array: &ArrayRef, | ||
| needle: &ArrayRef, | ||
| arr_n: &[i64], | ||
| ) -> Result<ArrayRef> { | ||
| match array.data_type() { | ||
| DataType::List(_) => { | ||
| let list_array = array.as_list::<i32>(); | ||
| general_remove_with_scalar::<i32>(list_array, needle, arr_n) | ||
| } | ||
| DataType::LargeList(_) => { | ||
| let list_array = array.as_list::<i64>(); | ||
| general_remove_with_scalar::<i64>(list_array, needle, arr_n) | ||
| } | ||
| array_type => exec_err!( | ||
| "array_remove/array_remove_n/array_remove_all does not support type '{array_type}'." | ||
| ), | ||
| } | ||
| } | ||
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| /// Removes elements matching a scalar needle from a list array. | ||
| /// | ||
| /// Uses a bulk `distinct` comparison for non-null, non-nested scalar elements, | ||
| /// falling back to the per-row `general_remove` path for null or nested types. | ||
| fn remove_with_scalar_needle( | ||
|
Contributor
There was a problem hiding this comment. I find this function a little confusing, since the code paths can then be like: Perhaps we can hoist this null/nested check earlier to remove need for this function? Or the benefits of centralizing the check outweighs it? |
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| list_array: &ArrayRef, | ||
| scalar_element: &ScalarValue, | ||
| arr_n: &[i64], | ||
| ) -> Result<ArrayRef> { | ||
| if !scalar_element.is_null() && !scalar_element.data_type().is_nested() { | ||
| let needle = scalar_element.to_array_of_size(1)?; | ||
| array_remove_dispatch_scalar(list_array, &needle, arr_n) | ||
| } else { | ||
| let needle_array = scalar_element.to_array_of_size(list_array.len())?; | ||
| array_remove_internal(list_array, &needle_array, arr_n) | ||
| } | ||
| } | ||
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| /// For each element of `list_array[i]`, removed up to `arr_n[i]` occurrences | ||
| /// of `element_array[i]`. | ||
| /// | ||
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@@ -468,6 +533,113 @@ fn general_remove<OffsetSize: OffsetSizeTrait>( | |
| )?)) | ||
| } | ||
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| /// For each element of `list_array[i]`, removed up to `arr_n[i]` occurrences | ||
| /// of `needle[0]` (scalar element broadcasted). | ||
| /// | ||
| /// This is a specialized version of `general_remove` for scalar elements that | ||
| /// uses bulk comparison for better performance. | ||
| fn general_remove_with_scalar<OffsetSize: OffsetSizeTrait>( | ||
| list_array: &GenericListArray<OffsetSize>, | ||
| needle: &ArrayRef, | ||
| arr_n: &[i64], | ||
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Comment on lines
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Contributor
There was a problem hiding this comment. Similar question to that of array_replace PR, in if we should just handle when needle & max are scalars only |
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| ) -> Result<ArrayRef> { | ||
| let list_field = match list_array.data_type() { | ||
| DataType::List(field) | DataType::LargeList(field) => field, | ||
| _ => { | ||
| return exec_err!( | ||
| "Expected List or LargeList data type, got {:?}", | ||
| list_array.data_type() | ||
| ); | ||
| } | ||
| }; | ||
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| let list_offsets = list_array.offsets(); | ||
| let first_offset = list_offsets[0].to_usize().unwrap(); | ||
| let last_offset = list_offsets[list_offsets.len() - 1].to_usize().unwrap(); | ||
| let values_range_len = last_offset - first_offset; | ||
| let values_slice = list_array.values().slice(first_offset, values_range_len); | ||
| let original_data = values_slice.to_data(); | ||
| let mut offsets = Vec::<OffsetSize>::with_capacity(list_array.len() + 1); | ||
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| offsets.push(OffsetSize::zero()); | ||
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| let mut mutable = MutableArrayData::with_capacities( | ||
|
Contributor
There was a problem hiding this comment. I wonder if an approach using |
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| vec![&original_data], | ||
| false, | ||
| Capacities::Array(original_data.len()), | ||
| ); | ||
| let nulls = list_array.nulls().cloned(); | ||
| let keep_mask = | ||
| arrow_ord::cmp::distinct(list_array.values(), &Scalar::new(Arc::clone(needle)))?; | ||
|
Contributor
There was a problem hiding this comment. This will call the distinct kernel on all the elements in the value buffer, not just the ones that are visible in a sliced array. |
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| let remove_bits = match keep_mask.nulls() { | ||
|
Contributor
There was a problem hiding this comment.
https://docs.rs/arrow/latest/arrow/compute/kernels/cmp/fn.distinct.html I don't think we should have handling around the null buffer of |
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| Some(validity) => !(&(keep_mask.values() & validity.inner())), | ||
| None => !keep_mask.values(), | ||
| }; | ||
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| for (row_index, offset_window) in list_offsets.windows(2).enumerate() { | ||
| if nulls.as_ref().is_some_and(|nulls| nulls.is_null(row_index)) { | ||
| offsets.push(offsets[row_index]); | ||
| continue; | ||
| } | ||
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| let start = offset_window[0].to_usize().unwrap() - first_offset; | ||
| let end = offset_window[1].to_usize().unwrap() - first_offset; | ||
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| let n = arr_n[row_index]; | ||
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| if n <= 0 { | ||
| mutable.extend(0, start, end); | ||
| offsets.push(offsets[row_index] + OffsetSize::usize_as(end - start)); | ||
| continue; | ||
| } | ||
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| let row_len = end - start; | ||
| let row_remove_bits = remove_bits.slice(first_offset + start, row_len); | ||
| let num_to_remove = row_remove_bits.count_set_bits(); | ||
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| if num_to_remove == 0 { | ||
| mutable.extend(0, start, end); | ||
| offsets.push(offsets[row_index] + OffsetSize::usize_as(row_len)); | ||
| continue; | ||
| } | ||
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| let max_removals = n.min(num_to_remove as i64) as usize; | ||
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| // Iterate only over the positions that need removal using set_indices, | ||
| // which is more efficient than scanning every bit. | ||
|
Contributor
There was a problem hiding this comment. Might be worth elaborating that the win here is mostly because we expect the # of values-to-remove is a lot smaller than the total array size, which it usually (but not always) will be. |
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| let mut removed = 0usize; | ||
| let mut copied = 0usize; | ||
| let mut prev_end = start; // end of last copied range (absolute index into values_slice) | ||
| for remove_pos in row_remove_bits.set_indices() { | ||
| let abs_pos = start + remove_pos; | ||
| // Copy the range before this removal position | ||
| if abs_pos > prev_end { | ||
| mutable.extend(0, prev_end, abs_pos); | ||
| copied += abs_pos - prev_end; | ||
| } | ||
| prev_end = abs_pos + 1; | ||
| removed += 1; | ||
| if removed == max_removals { | ||
| break; | ||
| } | ||
| } | ||
| // Copy the remaining tail after the last removal | ||
| if prev_end < end { | ||
| mutable.extend(0, prev_end, end); | ||
| copied += end - prev_end; | ||
| } | ||
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| offsets.push(offsets[row_index] + OffsetSize::usize_as(copied)); | ||
| } | ||
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| let new_values = make_array(mutable.freeze()); | ||
| Ok(Arc::new(GenericListArray::<OffsetSize>::try_new( | ||
| Arc::clone(list_field), | ||
| OffsetBuffer::new(offsets.into()), | ||
| new_values, | ||
| nulls, | ||
| )?)) | ||
| } | ||
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| #[cfg(test)] | ||
| mod tests { | ||
| use crate::remove::{ArrayRemove, ArrayRemoveAll, ArrayRemoveN}; | ||
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We're ignoring nulls in
max_arghere, though I think this may be an existing issue