primitive_array.rs

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// 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.

use crate::arrow::array_reader::{read_records, ArrayReader};
use crate::arrow::record_reader::buffer::ScalarValue;
use crate::arrow::record_reader::RecordReader;
use crate::arrow::schema::parquet_to_arrow_field;
use crate::basic::Type as PhysicalType;
use crate::column::page::PageIterator;
use crate::data_type::DataType;
use crate::errors::{ParquetError, Result};
use crate::schema::types::ColumnDescPtr;
use arrow::array::{
    ArrayDataBuilder, ArrayRef, BooleanArray, BooleanBufferBuilder, Decimal128Array,
    Float32Array, Float64Array, Int32Array, Int64Array,
};
use arrow::buffer::Buffer;
use arrow::datatypes::DataType as ArrowType;
use std::any::Any;
use std::sync::Arc;

/// Primitive array readers are leaves of array reader tree. They accept page iterator
/// and read them into primitive arrays.
pub struct PrimitiveArrayReader<T>
where
    T: DataType,
    T::T: ScalarValue,
{
    data_type: ArrowType,
    pages: Box<dyn PageIterator>,
    def_levels_buffer: Option<Buffer>,
    rep_levels_buffer: Option<Buffer>,
    column_desc: ColumnDescPtr,
    record_reader: RecordReader<T>,
}

impl<T> PrimitiveArrayReader<T>
where
    T: DataType,
    T::T: ScalarValue,
{
    /// Construct primitive array reader.
    pub fn new(
        pages: Box<dyn PageIterator>,
        column_desc: ColumnDescPtr,
        arrow_type: Option<ArrowType>,
    ) -> Result<Self> {
        // Check if Arrow type is specified, else create it from Parquet type
        let data_type = match arrow_type {
            Some(t) => t,
            None => parquet_to_arrow_field(column_desc.as_ref())?
                .data_type()
                .clone(),
        };

        let record_reader = RecordReader::<T>::new(column_desc.clone());

        Ok(Self {
            data_type,
            pages,
            def_levels_buffer: None,
            rep_levels_buffer: None,
            column_desc,
            record_reader,
        })
    }
}

/// Implementation of primitive array reader.
impl<T> ArrayReader for PrimitiveArrayReader<T>
where
    T: DataType,
    T::T: ScalarValue,
{
    fn as_any(&self) -> &dyn Any {
        self
    }

    /// Returns data type of primitive array.
    fn get_data_type(&self) -> &ArrowType {
        &self.data_type
    }

    /// Reads at most `batch_size` records into array.
    fn next_batch(&mut self, batch_size: usize) -> Result<ArrayRef> {
        read_records(&mut self.record_reader, self.pages.as_mut(), batch_size)?;

        let target_type = self.get_data_type().clone();
        let arrow_data_type = match T::get_physical_type() {
            PhysicalType::BOOLEAN => ArrowType::Boolean,
            PhysicalType::INT32 => {
                match target_type {
                    ArrowType::UInt32 => {
                        // follow C++ implementation and use overflow/reinterpret cast from  i32 to u32 which will map
                        // `i32::MIN..0` to `(i32::MAX as u32)..u32::MAX`
                        ArrowType::UInt32
                    }
                    _ => ArrowType::Int32,
                }
            }
            PhysicalType::INT64 => {
                match target_type {
                    ArrowType::UInt64 => {
                        // follow C++ implementation and use overflow/reinterpret cast from  i64 to u64 which will map
                        // `i64::MIN..0` to `(i64::MAX as u64)..u64::MAX`
                        ArrowType::UInt64
                    }
                    _ => ArrowType::Int64,
                }
            }
            PhysicalType::FLOAT => ArrowType::Float32,
            PhysicalType::DOUBLE => ArrowType::Float64,
            PhysicalType::INT96
            | PhysicalType::BYTE_ARRAY
            | PhysicalType::FIXED_LEN_BYTE_ARRAY => {
                unreachable!(
                    "PrimitiveArrayReaders don't support complex physical types"
                );
            }
        };

        // Convert to arrays by using the Parquet physical type.
        // The physical types are then cast to Arrow types if necessary

        let mut record_data = self.record_reader.consume_record_data();

        if T::get_physical_type() == PhysicalType::BOOLEAN {
            let mut boolean_buffer = BooleanBufferBuilder::new(record_data.len());

            for e in record_data.as_slice() {
                boolean_buffer.append(*e > 0);
            }
            record_data = boolean_buffer.finish();
        }

        let array_data = ArrayDataBuilder::new(arrow_data_type)
            .len(self.record_reader.num_values())
            .add_buffer(record_data)
            .null_bit_buffer(self.record_reader.consume_bitmap_buffer());

        let array_data = unsafe { array_data.build_unchecked() };
        let array = match T::get_physical_type() {
            PhysicalType::BOOLEAN => Arc::new(BooleanArray::from(array_data)) as ArrayRef,
            PhysicalType::INT32 => Arc::new(Int32Array::from(array_data)) as ArrayRef,
            PhysicalType::INT64 => Arc::new(Int64Array::from(array_data)) as ArrayRef,
            PhysicalType::FLOAT => Arc::new(Float32Array::from(array_data)) as ArrayRef,
            PhysicalType::DOUBLE => Arc::new(Float64Array::from(array_data)) as ArrayRef,
            PhysicalType::INT96
            | PhysicalType::BYTE_ARRAY
            | PhysicalType::FIXED_LEN_BYTE_ARRAY => {
                unreachable!(
                    "PrimitiveArrayReaders don't support complex physical types"
                );
            }
        };

        // cast to Arrow type
        // We make a strong assumption here that the casts should be infallible.
        // If the cast fails because of incompatible datatypes, then there might
        // be a bigger problem with how Arrow schemas are converted to Parquet.
        //
        // As there is not always a 1:1 mapping between Arrow and Parquet, there
        // are datatypes which we must convert explicitly.
        // These are:
        // - date64: we should cast int32 to date32, then date32 to date64.
        let array = match target_type {
            ArrowType::Date64 => {
                // this is cheap as it internally reinterprets the data
                let a = arrow::compute::cast(&array, &ArrowType::Date32)?;
                arrow::compute::cast(&a, &target_type)?
            }
            ArrowType::Decimal(p, s) => {
                let array = match array.data_type() {
                    ArrowType::Int32 => array
                        .as_any()
                        .downcast_ref::<Int32Array>()
                        .unwrap()
                        .iter()
                        .map(|v| v.map(|v| v.into()))
                        .collect::<Decimal128Array>(),

                    ArrowType::Int64 => array
                        .as_any()
                        .downcast_ref::<Int64Array>()
                        .unwrap()
                        .iter()
                        .map(|v| v.map(|v| v.into()))
                        .collect::<Decimal128Array>(),
                    _ => {
                        return Err(arrow_err!(
                            "Cannot convert {:?} to decimal",
                            array.data_type()
                        ))
                    }
                }
                .with_precision_and_scale(p, s)?;

                Arc::new(array) as ArrayRef
            }
            _ => arrow::compute::cast(&array, &target_type)?,
        };

        // save definition and repetition buffers
        self.def_levels_buffer = self.record_reader.consume_def_levels();
        self.rep_levels_buffer = self.record_reader.consume_rep_levels();
        self.record_reader.reset();
        Ok(array)
    }

    fn skip_records(&mut self, num_records: usize) -> Result<usize> {
        self.record_reader.skip_records(num_records)
    }

    fn get_def_levels(&self) -> Option<&[i16]> {
        self.def_levels_buffer.as_ref().map(|buf| buf.typed_data())
    }

    fn get_rep_levels(&self) -> Option<&[i16]> {
        self.rep_levels_buffer.as_ref().map(|buf| buf.typed_data())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::arrow::array_reader::test_util::EmptyPageIterator;
    use crate::basic::Encoding;
    use crate::column::page::Page;
    use crate::data_type::Int32Type;
    use crate::schema::parser::parse_message_type;
    use crate::schema::types::SchemaDescriptor;
    use crate::util::test_common::make_pages;
    use crate::util::InMemoryPageIterator;
    use arrow::array::PrimitiveArray;
    use arrow::datatypes::ArrowPrimitiveType;

    use rand::distributions::uniform::SampleUniform;
    use std::collections::VecDeque;

    fn make_column_chunks<T: DataType>(
        column_desc: ColumnDescPtr,
        encoding: Encoding,
        num_levels: usize,
        min_value: T::T,
        max_value: T::T,
        def_levels: &mut Vec<i16>,
        rep_levels: &mut Vec<i16>,
        values: &mut Vec<T::T>,
        page_lists: &mut Vec<Vec<Page>>,
        use_v2: bool,
        num_chunks: usize,
    ) where
        T::T: PartialOrd + SampleUniform + Copy,
    {
        for _i in 0..num_chunks {
            let mut pages = VecDeque::new();
            let mut data = Vec::new();
            let mut page_def_levels = Vec::new();
            let mut page_rep_levels = Vec::new();

            make_pages::<T>(
                column_desc.clone(),
                encoding,
                1,
                num_levels,
                min_value,
                max_value,
                &mut page_def_levels,
                &mut page_rep_levels,
                &mut data,
                &mut pages,
                use_v2,
            );

            def_levels.append(&mut page_def_levels);
            rep_levels.append(&mut page_rep_levels);
            values.append(&mut data);
            page_lists.push(Vec::from(pages));
        }
    }

    #[test]
    fn test_primitive_array_reader_empty_pages() {
        // Construct column schema
        let message_type = "
        message test_schema {
          REQUIRED INT32 leaf;
        }
        ";

        let schema = parse_message_type(message_type)
            .map(|t| Arc::new(SchemaDescriptor::new(Arc::new(t))))
            .unwrap();

        let column_desc = schema.column(0);
        let page_iterator = EmptyPageIterator::new(schema);

        let mut array_reader = PrimitiveArrayReader::<Int32Type>::new(
            Box::new(page_iterator),
            column_desc,
            None,
        )
        .unwrap();

        // expect no values to be read
        let array = array_reader.next_batch(50).unwrap();
        assert!(array.is_empty());
    }

    #[test]
    fn test_primitive_array_reader_data() {
        // Construct column schema
        let message_type = "
        message test_schema {
          REQUIRED INT32 leaf;
        }
        ";

        let schema = parse_message_type(message_type)
            .map(|t| Arc::new(SchemaDescriptor::new(Arc::new(t))))
            .unwrap();

        let column_desc = schema.column(0);

        // Construct page iterator
        {
            let mut data = Vec::new();
            let mut page_lists = Vec::new();
            make_column_chunks::<Int32Type>(
                column_desc.clone(),
                Encoding::PLAIN,
                100,
                1,
                200,
                &mut Vec::new(),
                &mut Vec::new(),
                &mut data,
                &mut page_lists,
                true,
                2,
            );
            let page_iterator =
                InMemoryPageIterator::new(schema, column_desc.clone(), page_lists);

            let mut array_reader = PrimitiveArrayReader::<Int32Type>::new(
                Box::new(page_iterator),
                column_desc,
                None,
            )
            .unwrap();

            // Read first 50 values, which are all from the first column chunk
            let array = array_reader.next_batch(50).unwrap();
            let array = array.as_any().downcast_ref::<Int32Array>().unwrap();

            assert_eq!(&Int32Array::from(data[0..50].to_vec()), array);

            // Read next 100 values, the first 50 ones are from the first column chunk,
            // and the last 50 ones are from the second column chunk
            let array = array_reader.next_batch(100).unwrap();
            let array = array.as_any().downcast_ref::<Int32Array>().unwrap();

            assert_eq!(&Int32Array::from(data[50..150].to_vec()), array);

            // Try to read 100 values, however there are only 50 values
            let array = array_reader.next_batch(100).unwrap();
            let array = array.as_any().downcast_ref::<Int32Array>().unwrap();

            assert_eq!(&Int32Array::from(data[150..200].to_vec()), array);
        }
    }

    macro_rules! test_primitive_array_reader_one_type {
        ($arrow_parquet_type:ty, $physical_type:expr, $converted_type_str:expr, $result_arrow_type:ty, $result_arrow_cast_type:ty, $result_primitive_type:ty) => {{
            let message_type = format!(
                "
            message test_schema {{
              REQUIRED {:?} leaf ({});
          }}
            ",
                $physical_type, $converted_type_str
            );
            let schema = parse_message_type(&message_type)
                .map(|t| Arc::new(SchemaDescriptor::new(Arc::new(t))))
                .unwrap();

            let column_desc = schema.column(0);

            // Construct page iterator
            {
                let mut data = Vec::new();
                let mut page_lists = Vec::new();
                make_column_chunks::<$arrow_parquet_type>(
                    column_desc.clone(),
                    Encoding::PLAIN,
                    100,
                    1,
                    200,
                    &mut Vec::new(),
                    &mut Vec::new(),
                    &mut data,
                    &mut page_lists,
                    true,
                    2,
                );
                let page_iterator = InMemoryPageIterator::new(
                    schema.clone(),
                    column_desc.clone(),
                    page_lists,
                );
                let mut array_reader = PrimitiveArrayReader::<$arrow_parquet_type>::new(
                    Box::new(page_iterator),
                    column_desc.clone(),
                    None,
                )
                .expect("Unable to get array reader");

                let array = array_reader
                    .next_batch(50)
                    .expect("Unable to get batch from reader");

                let result_data_type = <$result_arrow_type>::DATA_TYPE;
                let array = array
                    .as_any()
                    .downcast_ref::<PrimitiveArray<$result_arrow_type>>()
                    .expect(
                        format!(
                            "Unable to downcast {:?} to {:?}",
                            array.data_type(),
                            result_data_type
                        )
                        .as_str(),
                    );

                // create expected array as primitive, and cast to result type
                let expected = PrimitiveArray::<$result_arrow_cast_type>::from(
                    data[0..50]
                        .iter()
                        .map(|x| *x as $result_primitive_type)
                        .collect::<Vec<$result_primitive_type>>(),
                );
                let expected = Arc::new(expected) as ArrayRef;
                let expected = arrow::compute::cast(&expected, &result_data_type)
                    .expect("Unable to cast expected array");
                assert_eq!(expected.data_type(), &result_data_type);
                let expected = expected
                    .as_any()
                    .downcast_ref::<PrimitiveArray<$result_arrow_type>>()
                    .expect(
                        format!(
                            "Unable to downcast expected {:?} to {:?}",
                            expected.data_type(),
                            result_data_type
                        )
                        .as_str(),
                    );
                assert_eq!(expected, array);
            }
        }};
    }

    #[test]
    fn test_primitive_array_reader_temporal_types() {
        test_primitive_array_reader_one_type!(
            crate::data_type::Int32Type,
            PhysicalType::INT32,
            "DATE",
            arrow::datatypes::Date32Type,
            arrow::datatypes::Int32Type,
            i32
        );
        test_primitive_array_reader_one_type!(
            crate::data_type::Int32Type,
            PhysicalType::INT32,
            "TIME_MILLIS",
            arrow::datatypes::Time32MillisecondType,
            arrow::datatypes::Int32Type,
            i32
        );
        test_primitive_array_reader_one_type!(
            crate::data_type::Int64Type,
            PhysicalType::INT64,
            "TIME_MICROS",
            arrow::datatypes::Time64MicrosecondType,
            arrow::datatypes::Int64Type,
            i64
        );
        test_primitive_array_reader_one_type!(
            crate::data_type::Int64Type,
            PhysicalType::INT64,
            "TIMESTAMP_MILLIS",
            arrow::datatypes::TimestampMillisecondType,
            arrow::datatypes::Int64Type,
            i64
        );
        test_primitive_array_reader_one_type!(
            crate::data_type::Int64Type,
            PhysicalType::INT64,
            "TIMESTAMP_MICROS",
            arrow::datatypes::TimestampMicrosecondType,
            arrow::datatypes::Int64Type,
            i64
        );
    }

    #[test]
    fn test_primitive_array_reader_def_and_rep_levels() {
        // Construct column schema
        let message_type = "
        message test_schema {
            REPEATED Group test_mid {
                OPTIONAL INT32 leaf;
            }
        }
        ";

        let schema = parse_message_type(message_type)
            .map(|t| Arc::new(SchemaDescriptor::new(Arc::new(t))))
            .unwrap();

        let column_desc = schema.column(0);

        // Construct page iterator
        {
            let mut def_levels = Vec::new();
            let mut rep_levels = Vec::new();
            let mut page_lists = Vec::new();
            make_column_chunks::<Int32Type>(
                column_desc.clone(),
                Encoding::PLAIN,
                100,
                1,
                200,
                &mut def_levels,
                &mut rep_levels,
                &mut Vec::new(),
                &mut page_lists,
                true,
                2,
            );

            let page_iterator =
                InMemoryPageIterator::new(schema, column_desc.clone(), page_lists);

            let mut array_reader = PrimitiveArrayReader::<Int32Type>::new(
                Box::new(page_iterator),
                column_desc,
                None,
            )
            .unwrap();

            let mut accu_len: usize = 0;

            // Read first 50 values, which are all from the first column chunk
            let array = array_reader.next_batch(50).unwrap();
            assert_eq!(
                Some(&def_levels[accu_len..(accu_len + array.len())]),
                array_reader.get_def_levels()
            );
            assert_eq!(
                Some(&rep_levels[accu_len..(accu_len + array.len())]),
                array_reader.get_rep_levels()
            );
            accu_len += array.len();

            // Read next 100 values, the first 50 ones are from the first column chunk,
            // and the last 50 ones are from the second column chunk
            let array = array_reader.next_batch(100).unwrap();
            assert_eq!(
                Some(&def_levels[accu_len..(accu_len + array.len())]),
                array_reader.get_def_levels()
            );
            assert_eq!(
                Some(&rep_levels[accu_len..(accu_len + array.len())]),
                array_reader.get_rep_levels()
            );
            accu_len += array.len();

            // Try to read 100 values, however there are only 50 values
            let array = array_reader.next_batch(100).unwrap();
            assert_eq!(
                Some(&def_levels[accu_len..(accu_len + array.len())]),
                array_reader.get_def_levels()
            );
            assert_eq!(
                Some(&rep_levels[accu_len..(accu_len + array.len())]),
                array_reader.get_rep_levels()
            );
        }
    }
}