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Convert list array and non-list array to scalars #7862

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3472b51
list/non-list conversion
jayzhan211 Dec 9, 2023
d704c83
fix offset trait
jayzhan211 Dec 9, 2023
aee4eff
fmt
jayzhan211 Dec 9, 2023
b92d535
fmt
jayzhan211 Dec 13, 2023
3b6b53e
ci fix
jayzhan211 Dec 13, 2023
c69f874
add largetlist
jayzhan211 Dec 13, 2023
f7b6ac0
improve doc
jayzhan211 Dec 17, 2023
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139 changes: 115 additions & 24 deletions datafusion/common/src/scalar.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2039,7 +2039,11 @@ impl ScalarValue {
}
}

/// Retrieve ScalarValue for each row in `array`
/// Retrieve `ScalarValue` for each row in `array`
///
Comment on lines +2042 to +2043
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@alamb alamb Dec 16, 2023

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This seems left over

Suggested change
/// Retrieve `ScalarValue` for each row in `array`
///

/// Convert `ListArray` to `Vec<Vec<ScalarValue>>`, first `Vec` is for rows, second `Vec` is for elements in the list
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@alamb alamb Dec 16, 2023

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👍 It might also help to explain why we need two different signatures. It took me a while to grok things too

Suggested change
/// Convert `ListArray` to `Vec<Vec<ScalarValue>>`, first `Vec` is for rows, second `Vec` is for elements in the list
/// Convert `ListArray` into a 2 dimensional to `Vec<Vec<ScalarValue>>`, first `Vec` is for rows,
/// second `Vec` is for elements in the list.
///
/// See [`Self::convert_non_list_array_to_scalars`] for converting non Lists
///
/// This method is an optimization to unwrap nested ListArrays to nested Rust structures without
/// converting them twice

///
/// Return `Err` if `array` is not `ListArray`
///
/// Example
/// ```
Expand All @@ -2053,7 +2057,7 @@ impl ScalarValue {
/// Some(vec![Some(4), Some(5)])
/// ]);
///
/// let scalar_vec = ScalarValue::convert_array_to_scalar_vec(&list_arr).unwrap();
/// let scalar_vec = ScalarValue::convert_list_array_to_scalar_vec(&list_arr).unwrap();
///
/// let expected = vec![
/// vec![
Expand All @@ -2067,30 +2071,78 @@ impl ScalarValue {
///
/// assert_eq!(scalar_vec, expected);
/// ```
pub fn convert_array_to_scalar_vec(array: &dyn Array) -> Result<Vec<Vec<Self>>> {
let mut scalars = Vec::with_capacity(array.len());
pub fn convert_list_array_to_scalar_vec<O: OffsetSizeTrait>(
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@alamb alamb Dec 16, 2023

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I think this would be easier to use if it didn't mix generic and non generic code

Maybe something like

Suggested change
pub fn convert_list_array_to_scalar_vec<O: OffsetSizeTrait>(
pub fn convert_list_array_to_scalar_vec(
array: &dyn Array,
) -> Result<Vec<Vec<Self>>> {
if let Some(arr) = array.as_list_opt::<i32> {
Self::convert_list_array_to_scalar_vec_internal(arr)
} else if let Some(arr) = array.as_list_opt::<64> {
Self::convert_list_array_to_scalar_vec_internal(arr)
} else {
_internal_err!("Expected GenericListArray but found: {array:?}")
}
}

And then internally pass in the cast Array by changing

    fn convert_list_array_to_scalar_vec_internal<O: OffsetSizeTrait>(
        array: &dyn Array,
    ) -> Result<Vec<Vec<Self>>> {

to

    fn convert_list_array_to_scalar_vec_internal<O: OffsetSizeTrait>(
        array: &GenericListArray<O>,
    ) -> Result<Vec<Vec<Self>>> {

array: &dyn Array,
) -> Result<Vec<Vec<Self>>> {
if array.as_list_opt::<O>().is_some() {
Self::convert_list_array_to_scalar_vec_internal::<O>(array)
} else {
_internal_err!("Expected GenericListArray but found: {array:?}")
}
}

for index in 0..array.len() {
let scalar_values = match array.data_type() {
DataType::List(_) => {
let list_array = as_list_array(array);
match list_array.is_null(index) {
true => Vec::new(),
false => {
let nested_array = list_array.value(index);
ScalarValue::convert_array_to_scalar_vec(&nested_array)?
.into_iter()
.flatten()
.collect()
}
fn convert_list_array_to_scalar_vec_internal<O: OffsetSizeTrait>(
array: &dyn Array,
) -> Result<Vec<Vec<Self>>> {
let mut scalars_vec = Vec::with_capacity(array.len());

if let Some(list_arr) = array.as_list_opt::<O>() {
for index in 0..list_arr.len() {
let scalars = match list_arr.is_null(index) {
true => Vec::new(),
false => {
let nested_array = list_arr.value(index);
Self::convert_list_array_to_scalar_vec_internal::<O>(
&nested_array,
)?
.into_iter()
.flatten()
.collect()
}
}
_ => {
let scalar = ScalarValue::try_from_array(array, index)?;
vec![scalar]
}
};
scalars.push(scalar_values);
};
scalars_vec.push(scalars);
}
} else {
let scalars = ScalarValue::convert_non_list_array_to_scalars(array)?;
scalars_vec.push(scalars);
}

Ok(scalars_vec)
}

/// Convert non-ListArray to `Vec<ScalarValue>`
///
/// Return Err if `array` is ListArray
///
/// Example
/// ```
/// use datafusion_common::ScalarValue;
/// use arrow::array::Int32Array;
///
/// let list_arr = Int32Array::from(vec![Some(1), Some(2), Some(3), None, Some(4), Some(5)]);
///
/// let scalar_vec = ScalarValue::convert_non_list_array_to_scalars(&list_arr).unwrap();
///
/// let expected = vec![
/// ScalarValue::Int32(Some(1)),
/// ScalarValue::Int32(Some(2)),
/// ScalarValue::Int32(Some(3)),
/// ScalarValue::Int32(None),
/// ScalarValue::Int32(Some(4)),
/// ScalarValue::Int32(Some(5)),
/// ];
///
/// assert_eq!(scalar_vec, expected);
/// ```
pub fn convert_non_list_array_to_scalars(array: &dyn Array) -> Result<Vec<Self>> {
if array.as_list_opt::<i32>().is_some() || array.as_list_opt::<i64>().is_some() {
return _internal_err!("Expected non ListArray but found: {array:?}");
}

let mut scalars = Vec::with_capacity(array.len());
for index in 0..array.len() {
let scalar = ScalarValue::try_from_array(array, index)?;
scalars.push(scalar);
}
Ok(scalars)
}
Expand Down Expand Up @@ -3129,6 +3181,44 @@ mod tests {
use arrow_array::ArrowNumericType;

use crate::cast::{as_string_array, as_uint32_array, as_uint64_array};
use crate::utils::arrays_into_list_array;

#[test]
fn convert_list_array_to_scalar_vec_nested() {
let l1 = ListArray::from_iter_primitive::<Int32Type, _, _>(vec![
Some(vec![Some(1), Some(2), Some(3)]),
Some(vec![Some(4), Some(5)]),
]);

let l2 = ListArray::from_iter_primitive::<Int32Type, _, _>(vec![Some(vec![
Some(6),
Some(7),
Some(8),
])]);

let l1 = Arc::new(l1) as ArrayRef;
let l2 = Arc::new(l2) as ArrayRef;

let l12 = arrays_into_list_array([l1, l2]).unwrap();
let arr = Arc::new(l12) as ArrayRef;

let actual = ScalarValue::convert_list_array_to_scalar_vec::<i32>(&arr).unwrap();
let expected = vec![
vec![
ScalarValue::Int32(Some(1)),
ScalarValue::Int32(Some(2)),
ScalarValue::Int32(Some(3)),
ScalarValue::Int32(Some(4)),
ScalarValue::Int32(Some(5)),
],
vec![
ScalarValue::Int32(Some(6)),
ScalarValue::Int32(Some(7)),
ScalarValue::Int32(Some(8)),
],
];
assert_eq!(actual, expected);
}

#[test]
fn test_to_array_of_size_for_list() {
Expand Down Expand Up @@ -3188,6 +3278,7 @@ mod tests {
"arrow",
"data-fusion",
])));

let result = as_list_array(&array);
assert_eq!(result, &expected);
}
Expand Down
8 changes: 6 additions & 2 deletions datafusion/core/tests/sql/aggregates.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -45,13 +45,17 @@ async fn csv_query_array_agg_distinct() -> Result<()> {
let column = actual[0].column(0);
assert_eq!(column.len(), 1);

let scalar_vec = ScalarValue::convert_array_to_scalar_vec(&column)?;
let mut scalars = scalar_vec[0].clone();
// 1 row
let scalar_vec = ScalarValue::convert_list_array_to_scalar_vec::<i32>(&column)?;
let mut scalars = scalar_vec.first().unwrap().to_owned();

// workaround lack of Ord of ScalarValue
let cmp = |a: &ScalarValue, b: &ScalarValue| {
a.partial_cmp(b).expect("Can compare ScalarValues")
};

scalars.sort_by(cmp);

assert_eq!(
scalars,
vec![
Expand Down
28 changes: 13 additions & 15 deletions datafusion/physical-expr/src/aggregate/array_agg_distinct.rs
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Expand Up @@ -137,9 +137,18 @@ impl Accumulator for DistinctArrayAggAccumulator {
assert_eq!(values.len(), 1, "batch input should only include 1 column!");

let array = &values[0];
let scalars = ScalarValue::convert_array_to_scalar_vec(array)?;
for scalar in scalars {
self.values.extend(scalar)
match array.data_type() {
DataType::List(_) => {
let scalar_vec =
ScalarValue::convert_list_array_to_scalar_vec::<i32>(array)?;
for scalars in scalar_vec {
self.values.extend(scalars);
}
}
_ => {
let scalars = ScalarValue::convert_non_list_array_to_scalars(array)?;
self.values.extend(scalars);
}
}
Ok(())
}
Expand All @@ -149,18 +158,7 @@ impl Accumulator for DistinctArrayAggAccumulator {
return Ok(());
}

assert_eq!(
states.len(),
1,
"array_agg_distinct states must contain single array"
);

let scalar_vec = ScalarValue::convert_array_to_scalar_vec(&states[0])?;
for scalars in scalar_vec {
self.values.extend(scalars)
}

Ok(())
self.update_batch(states)
}

fn evaluate(&self) -> Result<ScalarValue> {
Expand Down
5 changes: 3 additions & 2 deletions datafusion/physical-expr/src/aggregate/array_agg_ordered.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -225,13 +225,14 @@ impl Accumulator for OrderSensitiveArrayAggAccumulator {
partition_ordering_values.push(self.ordering_values.clone());

let array_agg_res =
ScalarValue::convert_array_to_scalar_vec(array_agg_values)?;
ScalarValue::convert_list_array_to_scalar_vec::<i32>(array_agg_values)?;

for v in array_agg_res.into_iter() {
partition_values.push(v);
}

let orderings = ScalarValue::convert_array_to_scalar_vec(agg_orderings)?;
let orderings =
ScalarValue::convert_list_array_to_scalar_vec::<i32>(agg_orderings)?;

for partition_ordering_rows in orderings.into_iter() {
// Extract value from struct to ordering_rows for each group/partition
Expand Down
3 changes: 2 additions & 1 deletion datafusion/physical-expr/src/aggregate/count_distinct.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,8 @@ impl Accumulator for DistinctCountAccumulator {
return Ok(());
}
assert_eq!(states.len(), 1, "array_agg states must be singleton!");
let scalar_vec = ScalarValue::convert_array_to_scalar_vec(&states[0])?;
let scalar_vec =
ScalarValue::convert_list_array_to_scalar_vec::<i32>(&states[0])?;
for scalars in scalar_vec.into_iter() {
self.values.extend(scalars)
}
Expand Down