Skip to content

[WIP] fix: read Dict(FixedSizeBinary) from parquet without dict encoding #10232

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
Jefffrey wants to merge 1 commit into
base: main
Choose a base branch
from
+17 −13
Draft

[WIP] fix: read Dict(FixedSizeBinary) from parquet without dict encoding #10232

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 6 additions & 12 deletions parquet/src/arrow/arrow_writer/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2933,16 +2933,6 @@ mod tests {
K::Native: FromPrimitive + ToPrimitive + TryFrom<u8>,
<<K as arrow_array::ArrowPrimitiveType>::Native as TryFrom<u8>>::Error: std::fmt::Debug,
{
let field = Field::new(
"a",
DataType::Dictionary(
Box::new(K::DATA_TYPE),
Box::new(DataType::FixedSizeBinary(4)),
),
false,
);
let schema = Schema::new(vec![field]);

let keys: Vec<K::Native> = vec![
K::Native::try_from(0u8).unwrap(),
K::Native::try_from(0u8).unwrap(),
Expand All @@ -2954,8 +2944,12 @@ mod tests {
)
.unwrap();

let data = DictionaryArray::<K>::new(keys, Arc::new(values));
let batch = RecordBatch::try_new(Arc::new(schema), vec![Arc::new(data)]).unwrap();
let data = Arc::new(DictionaryArray::<K>::new(keys, Arc::new(values))) as ArrayRef;
one_column_roundtrip(Arc::clone(&data), true);

@Jefffrey Jefffrey Jun 29, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

From the reproduction, added one_column_roundtrip() usage here to test roundtrip where one of the cases is disabling dictionary encoding entirely

Rest of test changes is just restructuring


let field = Field::new("a", data.data_type().clone(), false);
let schema = Schema::new(vec![field]);
let batch = RecordBatch::try_new(Arc::new(schema), vec![data]).unwrap();
roundtrip(batch, None);
}

Expand Down
12 changes: 11 additions & 1 deletion parquet/src/arrow/buffer/dictionary_buffer.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -185,8 +185,18 @@ impl<K: ArrowNativeType + Ord, V: OffsetSizeTrait> DictionaryBuffer<K, V> {
ArrowType::Dictionary(k, v) => (k, v.as_ref().clone()),
_ => unreachable!(),
};
let array = if let ArrowType::FixedSizeBinary(size) = value_type {

@Jefffrey Jefffrey Jun 29, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Matching what was done above in the Self::Dict path:

arrow-rs/parquet/src/arrow/buffer/dictionary_buffer.rs

Lines 159 to 168 in 7616e10

let values = if let ArrowType::FixedSizeBinary(size) = **value_type {
let binary = values.as_binary::<i32>();
Arc::new(FixedSizeBinaryArray::new(
size,
binary.values().clone(),
binary.nulls().cloned(),
)) as _
} else {
values
};

This is because values.into_array() assumed a generic byte offset array:

arrow-rs/parquet/src/arrow/buffer/offset_buffer.rs

Lines 132 to 146 in 7616e10

/// Converts this into an [`ArrayRef`] with the provided `data_type` and `null_buffer`
pub fn into_array(self, null_buffer: Option<Buffer>, data_type: ArrowType) -> ArrayRef {
let array_data_builder = ArrayDataBuilder::new(data_type)
.len(self.len())
.add_buffer(Buffer::from_vec(self.offsets))
.add_buffer(Buffer::from_vec(self.values))
.null_bit_buffer(null_buffer);
let data = match cfg!(debug_assertions) {
true => array_data_builder.build().unwrap(),
false => unsafe { array_data_builder.build_unchecked() },
};
make_array(data)
}

Which is the wrong structure for a fixedsizebinary array (we don't have offsets buffer, etc.)

let array = values.into_array(null_buffer, ArrowType::Binary);
let array = array.as_binary::<i32>();
Arc::new(FixedSizeBinaryArray::new(
size,
array.values().clone(),
array.nulls().cloned(),
)) as _
} else {
values.into_array(null_buffer, value_type)
};

let array = values.into_array(null_buffer, value_type);
pack_values(key_type, &array)
}
}
Expand Down
Loading