alamb commented on code in PR #7905:
URL: https://github.com/apache/arrow-rs/pull/7905#discussion_r2202839050
##########
parquet-variant-compute/src/from_json.rs:
##########
@@ -135,43 +68,38 @@ mod test {
None,
]);
let array_ref: ArrayRef = Arc::new(input);
- let output = batch_json_string_to_variant(&array_ref).unwrap();
+ let variant_array = batch_json_string_to_variant(&array_ref).unwrap();
- let struct_array = &output;
- let metadata_array = struct_array
- .column(0)
- .as_any()
- .downcast_ref::<BinaryArray>()
- .unwrap();
- let value_array = struct_array
- .column(1)
- .as_any()
- .downcast_ref::<BinaryArray>()
- .unwrap();
+ let metadata_array = variant_array.metadata_field().as_binary_view();
+ let value_array = variant_array.value_field().as_binary_view();
- assert!(!struct_array.is_null(0));
- assert!(struct_array.is_null(1));
- assert!(!struct_array.is_null(2));
- assert!(!struct_array.is_null(3));
- assert!(struct_array.is_null(4));
+ // Compare row 0
+ assert!(!variant_array.is_null(0));
+ assert_eq!(variant_array.value(0), Variant::Int8(1));
Review Comment:
I haven't fully worked out in my head how this will work for shredded
Variants -- specifically how to avoid copying stuff around when accessing a
shredded variant. We'll have to figure that out in follow on PRs
##########
parquet-variant-compute/src/from_json.rs:
##########
@@ -18,109 +18,42 @@
//! Module for transforming a batch of JSON strings into a batch of Variants
represented as
//! STRUCT<metadata: BINARY, value: BINARY>
-use std::sync::Arc;
-
-use arrow::array::{Array, ArrayRef, BinaryArray, BooleanBufferBuilder,
StringArray, StructArray};
-use arrow::buffer::{Buffer, NullBuffer, OffsetBuffer, ScalarBuffer};
-use arrow::datatypes::{DataType, Field};
+use crate::{VariantArray, VariantArrayBuilder};
+use arrow::array::{Array, ArrayRef, StringArray};
use arrow_schema::ArrowError;
use parquet_variant::VariantBuilder;
use parquet_variant_json::json_to_variant;
-fn variant_arrow_repr() -> DataType {
- // The subfields are expected to be non-nullable according to the parquet
variant spec.
- let metadata_field = Field::new("metadata", DataType::Binary, false);
- let value_field = Field::new("value", DataType::Binary, false);
- let fields = vec![metadata_field, value_field];
- DataType::Struct(fields.into())
-}
-
/// Parse a batch of JSON strings into a batch of Variants represented as
/// STRUCT<metadata: BINARY, value: BINARY> where nulls are preserved. The
JSON strings in the input
/// must be valid.
-pub fn batch_json_string_to_variant(input: &ArrayRef) -> Result<StructArray,
ArrowError> {
+pub fn batch_json_string_to_variant(input: &ArrayRef) -> Result<VariantArray,
ArrowError> {
let input_string_array = match
input.as_any().downcast_ref::<StringArray>() {
Some(string_array) => Ok(string_array),
None => Err(ArrowError::CastError(
"Expected reference to StringArray as input".into(),
)),
}?;
- // Zero-copy builders
- let mut metadata_buffer: Vec<u8> = Vec::with_capacity(input.len() * 128);
- let mut metadata_offsets: Vec<i32> = Vec::with_capacity(input.len() + 1);
- let mut metadata_validity = BooleanBufferBuilder::new(input.len());
- let mut metadata_current_offset: i32 = 0;
- metadata_offsets.push(metadata_current_offset);
-
- let mut value_buffer: Vec<u8> = Vec::with_capacity(input.len() * 128);
- let mut value_offsets: Vec<i32> = Vec::with_capacity(input.len() + 1);
- let mut value_validity = BooleanBufferBuilder::new(input.len());
- let mut value_current_offset: i32 = 0;
- value_offsets.push(value_current_offset);
-
- let mut validity = BooleanBufferBuilder::new(input.len());
+ let mut variant_array_builder =
VariantArrayBuilder::new(input_string_array.len());
for i in 0..input.len() {
if input.is_null(i) {
// The subfields are expected to be non-nullable according to the
parquet variant spec.
- metadata_validity.append(true);
- value_validity.append(true);
- metadata_offsets.push(metadata_current_offset);
- value_offsets.push(value_current_offset);
- validity.append(false);
+ variant_array_builder.append_null();
} else {
let mut vb = VariantBuilder::new();
json_to_variant(input_string_array.value(i), &mut vb)?;
let (metadata, value) = vb.finish();
- validity.append(true);
-
- metadata_current_offset += metadata.len() as i32;
- metadata_buffer.extend(metadata);
- metadata_offsets.push(metadata_current_offset);
- metadata_validity.append(true);
-
- value_current_offset += value.len() as i32;
- value_buffer.extend(value);
- value_offsets.push(value_current_offset);
- value_validity.append(true);
+ variant_array_builder.append_variant_buffers(&metadata, &value);
Review Comment:
This is what I came up with
- https://github.com/apache/arrow-rs/pull/7911
##########
parquet-variant-compute/src/variant_array.rs:
##########
@@ -0,0 +1,227 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! [`VariantArray`] implementation
+
+use arrow::array::{Array, ArrayData, ArrayRef, AsArray, StructArray};
+use arrow::buffer::NullBuffer;
+use arrow_schema::{ArrowError, DataType};
+use parquet_variant::Variant;
+use std::any::Any;
+use std::sync::Arc;
+
+/// An array of Parquet [`Variant`] values
+///
+/// A [`VariantArray`] wraps an Arrow [`StructArray`] that stores the
underlying
+/// `metadata` and `value` fields, and adds convenience methods to access
+/// the `Variant`s
+///
+/// See [`VariantArrayBuilder`] for constructing a `VariantArray`.
+///
+/// [`VariantArrayBuilder`]: crate::VariantArrayBuilder
+///
+/// # Specification
+/// 1. This code follows the conventions for storing variants in Arrow Struct
Array
+/// defined by [Extension Type for Parquet Variant arrow] and this
[document].
+/// At the time of this writing, this is not yet a standardized Arrow
extension type.
+///
+/// [Extension Type for Parquet Variant arrow]:
https://github.com/apache/arrow/issues/46908
+/// [document]:
https://docs.google.com/document/d/1pw0AWoMQY3SjD7R4LgbPvMjG_xSCtXp3rZHkVp9jpZ4/edit?usp=sharing
+#[derive(Debug)]
+pub struct VariantArray {
+ /// StructArray or up to three fields:
+ /// 1. A required field named metadata which is binary, large_binary, or
binary_view
+ /// 2. An optional field named value that is binary, large_binary, or
binary_view
+ /// 3. An optional field named typed_value which can be any primitive type
or be a list, large_list, list_view or struct
+ ///
+ /// If typed_value is a nested type, its elements must be required and must
+ /// be a struct containing only one of the following:
+ ///
+ /// 1. A single required field, of type binary, large_binary, or
binary_view named value
+ ///
+ /// 2. An optional field named value of type binary, large_binary, or
+ /// binary_view AND an optional field named typed_value which follows
these
+ /// same rules
Review Comment:
I agree -- I think I did not read the proposal correctly. I will correct the
wording
https://docs.google.com/document/d/1pw0AWoMQY3SjD7R4LgbPvMjG_xSCtXp3rZHkVp9jpZ4/edit?tab=t.0#heading=h.ru2zdn2szuc4
##########
parquet-variant-compute/src/variant_array.rs:
##########
@@ -0,0 +1,227 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! [`VariantArray`] implementation
+
+use arrow::array::{Array, ArrayData, ArrayRef, AsArray, StructArray};
+use arrow::buffer::NullBuffer;
+use arrow_schema::{ArrowError, DataType};
+use parquet_variant::Variant;
+use std::any::Any;
+use std::sync::Arc;
+
+/// An array of Parquet [`Variant`] values
+///
+/// A [`VariantArray`] wraps an Arrow [`StructArray`] that stores the
underlying
+/// `metadata` and `value` fields, and adds convenience methods to access
+/// the `Variant`s
+///
+/// See [`VariantArrayBuilder`] for constructing a `VariantArray`.
+///
+/// [`VariantArrayBuilder`]: crate::VariantArrayBuilder
+///
+/// # Specification
+/// 1. This code follows the conventions for storing variants in Arrow Struct
Array
+/// defined by [Extension Type for Parquet Variant arrow] and this
[document].
+/// At the time of this writing, this is not yet a standardized Arrow
extension type.
+///
+/// [Extension Type for Parquet Variant arrow]:
https://github.com/apache/arrow/issues/46908
+/// [document]:
https://docs.google.com/document/d/1pw0AWoMQY3SjD7R4LgbPvMjG_xSCtXp3rZHkVp9jpZ4/edit?usp=sharing
+#[derive(Debug)]
+pub struct VariantArray {
+ /// StructArray or up to three fields:
+ /// 1. A required field named metadata which is binary, large_binary, or
binary_view
+ /// 2. An optional field named value that is binary, large_binary, or
binary_view
+ /// 3. An optional field named typed_value which can be any primitive type
or be a list, large_list, list_view or struct
+ ///
+ /// If typed_value is a nested type, its elements must be required and must
+ /// be a struct containing only one of the following:
+ ///
+ /// 1. A single required field, of type binary, large_binary, or
binary_view named value
+ ///
+ /// 2. An optional field named value of type binary, large_binary, or
+ /// binary_view AND an optional field named typed_value which follows
these
+ /// same rules
+ ///
+ /// NOTE: It is also permissible for the metadata field to be
+ /// Dictionary-Encoded, preferably (but not required) with an index type of
+ /// int8.
+ inner: StructArray,
Review Comment:
I filed a ticket to track
- https://github.com/apache/arrow-rs/issues/7920
##########
parquet-variant-compute/src/variant_array.rs:
##########
@@ -0,0 +1,227 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+//! [`VariantArray`] implementation
+
+use arrow::array::{Array, ArrayData, ArrayRef, AsArray, StructArray};
+use arrow::buffer::NullBuffer;
+use arrow_schema::{ArrowError, DataType};
+use parquet_variant::Variant;
+use std::any::Any;
+use std::sync::Arc;
+
+/// An array of Parquet [`Variant`] values
+///
+/// A [`VariantArray`] wraps an Arrow [`StructArray`] that stores the
underlying
+/// `metadata` and `value` fields, and adds convenience methods to access
+/// the `Variant`s
+///
+/// See [`VariantArrayBuilder`] for constructing a `VariantArray`.
+///
+/// [`VariantArrayBuilder`]: crate::VariantArrayBuilder
+///
+/// # Specification
+/// 1. This code follows the conventions for storing variants in Arrow Struct
Array
+/// defined by [Extension Type for Parquet Variant arrow] and this
[document].
+/// At the time of this writing, this is not yet a standardized Arrow
extension type.
+///
+/// [Extension Type for Parquet Variant arrow]:
https://github.com/apache/arrow/issues/46908
+/// [document]:
https://docs.google.com/document/d/1pw0AWoMQY3SjD7R4LgbPvMjG_xSCtXp3rZHkVp9jpZ4/edit?usp=sharing
+#[derive(Debug)]
+pub struct VariantArray {
+ /// StructArray or up to three fields:
+ /// 1. A required field named metadata which is binary, large_binary, or
binary_view
+ /// 2. An optional field named value that is binary, large_binary, or
binary_view
+ /// 3. An optional field named typed_value which can be any primitive type
or be a list, large_list, list_view or struct
+ ///
+ /// If typed_value is a nested type, its elements must be required and must
+ /// be a struct containing only one of the following:
+ ///
+ /// 1. A single required field, of type binary, large_binary, or
binary_view named value
+ ///
+ /// 2. An optional field named value of type binary, large_binary, or
+ /// binary_view AND an optional field named typed_value which follows
these
+ /// same rules
+ ///
+ /// NOTE: It is also permissible for the metadata field to be
+ /// Dictionary-Encoded, preferably (but not required) with an index type of
+ /// int8.
+ inner: StructArray,
+}
+
+impl VariantArray {
+ /// Creates a new `VariantArray` from a [`StructArray`].
+ ///
+ /// # Arguments
+ /// - `inner` - The underlying [`StructArray`] that contains the variant
data.
+ ///
+ /// # Returns
+ /// - A new instance of `VariantArray`.
+ ///
+ /// # Errors:
+ /// If the `StructArray` does not contain the required fields
+ pub fn try_new(inner: ArrayRef) -> Result<Self, ArrowError> {
+ let Some(inner) = inner.as_struct_opt() else {
+ return Err(ArrowError::InvalidArgumentError(
+ "Invalid VariantArray: requires StructArray as
input".to_string(),
+ ));
+ };
+ // Ensure the StructArray has the expected fields
+ if !inner.fields().iter().any(|f| f.name() == "metadata") {
+ return Err(ArrowError::InvalidArgumentError(
+ "Invalid VariantArray: StructArray must contain a 'metadata'
field".to_string(),
+ ));
+ }
+ if !inner.fields().iter().any(|f| f.name() == "value") {
+ return Err(ArrowError::InvalidArgumentError(
+ "Invalid VariantArray: StructArray must contain a 'value'
field".to_string(),
+ ));
+ }
Review Comment:
I don't know either
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