alamb commented on a change in pull request #8303:
URL: https://github.com/apache/arrow/pull/8303#discussion_r497405581
##########
File path: rust/arrow/src/compute/kernels/filter.rs
##########
@@ -353,15 +353,19 @@ impl FilterContext {
// foreach bit in batch:
if (filter_batch & self.filter_mask[j]) != 0 {
let data_index = (i * 64) + j;
- values.push(input_array.value(data_index));
+ if input_array.is_null(data_index) {
+ values.push(None)
+ } else {
+
values.push(Some(input_array.value(data_index)))
+ }
}
}
}
Ok(Arc::new(BinaryArray::from(values)))
}
DataType::Utf8 => {
let input_array =
array.as_any().downcast_ref::<StringArray>().unwrap();
- let mut values: Vec<&str> =
Vec::with_capacity(self.filtered_count);
+ let mut values: Vec<Option<&str>> =
Vec::with_capacity(self.filtered_count);
Review comment:
> Doesn't an Option of a reference leverages null pointer optimization
(on which None is represented by the null pointer, e.g. rust-lang/rust#9378)?
Yes, I believe you are correct.
This program:
```
fn main() {
println!("The size of a &str is {}", std::mem::size_of::<&str>());
println!("The size of an Option<&str> is {}",
std::mem::size_of::<Option<&str>>());
}
```
Produces the following on my machine:
```
The size of a &str is 16
The size of an Option<&str> is 16
```
##########
File path: rust/arrow/src/array/array.rs
##########
@@ -1267,6 +1267,36 @@ impl<OffsetSize: OffsetSizeTrait>
GenericBinaryArray<OffsetSize> {
GenericBinaryArray::<OffsetSize>::from(array_data)
}
+ fn from_opt_vec(v: Vec<Option<&[u8]>>, data_type: DataType) -> Self {
Review comment:
It is tested (indirectly) in
https://github.com/apache/arrow/pull/8303/files#diff-d7b0b7cde1850e8744ceda458c6dea81R700
-- but I think a more specific test would be valuable. I will add one.
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