tustvold commented on code in PR #1682: URL: https://github.com/apache/arrow-rs/pull/1682#discussion_r872203199
########## parquet/src/arrow/schema/primitive.rs: ########## @@ -0,0 +1,266 @@ +// 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. + +use crate::basic::{ + ConvertedType, LogicalType, TimeUnit as ParquetTimeUnit, Type as PhysicalType, +}; +use crate::errors::{ParquetError, Result}; +use crate::schema::types::{BasicTypeInfo, Type}; +use arrow::datatypes::{DataType, IntervalUnit, TimeUnit}; + +/// Converts [`Type`] to [`DataType`] with an optional `arrow_type_hint` +/// provided by the arrow schema +/// +/// Note: the values embedded in the schema are advisory, +pub fn convert_primitive( + parquet_type: &Type, + arrow_type_hint: Option<DataType>, +) -> Result<DataType> { + let physical_type = from_parquet(parquet_type)?; + Ok(match arrow_type_hint { + Some(hint) => apply_hint(physical_type, hint), + None => physical_type, + }) +} + +/// Uses an type hint from the embedded arrow schema to aid in faithfully +/// reproducing the data as it was written into parquet +fn apply_hint(parquet: DataType, hint: DataType) -> DataType { + match (&parquet, &hint) { + // Not all time units can be represented as LogicalType / ConvertedType + (DataType::Int32 | DataType::Int64, DataType::Timestamp(_, _)) => hint, + (DataType::Int32, DataType::Time32(_)) => hint, + (DataType::Int64, DataType::Time64(_)) => hint, + + // Date64 doesn't have a corresponding LogicalType / ConvertedType + (DataType::Int64, DataType::Date64) => hint, + + // Coerce Date32 back to Date64 (#1666) + (DataType::Date32, DataType::Date64) => hint, + + // Determine timezone + (DataType::Timestamp(p, None), DataType::Timestamp(h, Some(_))) if p == h => hint, + + // Determine offset size + (DataType::Utf8, DataType::LargeUtf8) => hint, + (DataType::Binary, DataType::LargeBinary) => hint, + + // Determine interval time unit (#1666) + (DataType::Interval(_), DataType::Interval(_)) => hint, + + // Potentially preserve dictionary encoding + (_, DataType::Dictionary(_, value)) => { + // Apply hint to inner type + let hinted = apply_hint(parquet, value.as_ref().clone()); + + // If matches dictionary value - preserve dictionary + // otherwise use hinted inner type + match &hinted == value.as_ref() { + true => hint, + false => hinted, + } + } + _ => parquet, + } +} + +fn from_parquet(parquet_type: &Type) -> Result<DataType> { + match parquet_type { + Type::PrimitiveType { + physical_type, + basic_info, + type_length, + scale, + precision, + .. + } => match physical_type { + PhysicalType::BOOLEAN => Ok(DataType::Boolean), + PhysicalType::INT32 => from_int32(basic_info, *scale, *precision), + PhysicalType::INT64 => from_int64(basic_info, *scale, *precision), + PhysicalType::INT96 => Ok(DataType::Timestamp(TimeUnit::Nanosecond, None)), + PhysicalType::FLOAT => Ok(DataType::Float32), + PhysicalType::DOUBLE => Ok(DataType::Float64), + PhysicalType::BYTE_ARRAY => from_byte_array(basic_info), + PhysicalType::FIXED_LEN_BYTE_ARRAY => { + from_fixed_len_byte_array(basic_info, *scale, *precision, *type_length) + } + }, + Type::GroupType { .. } => unreachable!(), + } +} + +fn decimal_type(scale: i32, precision: i32) -> Result<DataType> { + let scale = scale + .try_into() + .map_err(|_| arrow_err!("scale cannot be negative: {}", scale))?; + + let precision = precision + .try_into() + .map_err(|_| arrow_err!("precision cannot be negative: {}", precision))?; + + Ok(DataType::Decimal(precision, scale)) +} + +fn from_int32(info: &BasicTypeInfo, scale: i32, precision: i32) -> Result<DataType> { + match (info.logical_type(), info.converted_type()) { + (None, ConvertedType::NONE) => Ok(DataType::Int32), + ( + Some( + ref t @ LogicalType::Integer { + bit_width, + is_signed, + }, + ), + _, + ) => match (bit_width, is_signed) { + (8, true) => Ok(DataType::Int8), + (16, true) => Ok(DataType::Int16), + (32, true) => Ok(DataType::Int32), + (8, false) => Ok(DataType::UInt8), + (16, false) => Ok(DataType::UInt16), + (32, false) => Ok(DataType::UInt32), + _ => Err(arrow_err!("Cannot create INT32 physical type from {:?}", t)), + }, + (Some(LogicalType::Decimal { scale, precision }), _) => { + decimal_type(scale, precision) + } + (Some(LogicalType::Date), _) => Ok(DataType::Date32), + (Some(LogicalType::Time { unit, .. }), _) => match unit { + ParquetTimeUnit::MILLIS(_) => Ok(DataType::Time32(TimeUnit::Millisecond)), + _ => Err(arrow_err!( + "Cannot create INT32 physical type from {:?}", + unit + )), + }, + // https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#unknown-always-null + (Some(LogicalType::Unknown), _) => Ok(DataType::Null), + (None, ConvertedType::UINT_8) => Ok(DataType::UInt8), + (None, ConvertedType::UINT_16) => Ok(DataType::UInt16), + (None, ConvertedType::UINT_32) => Ok(DataType::UInt32), + (None, ConvertedType::INT_8) => Ok(DataType::Int8), + (None, ConvertedType::INT_16) => Ok(DataType::Int16), + (None, ConvertedType::INT_32) => Ok(DataType::Int32), + (None, ConvertedType::DATE) => Ok(DataType::Date32), + (None, ConvertedType::TIME_MILLIS) => Ok(DataType::Time32(TimeUnit::Millisecond)), + (None, ConvertedType::DECIMAL) => decimal_type(scale, precision), + (logical, converted) => Err(arrow_err!( + "Unable to convert parquet INT32 logical type {:?} or converted type {}", + logical, + converted + )), + } +} + +fn from_int64(info: &BasicTypeInfo, scale: i32, precision: i32) -> Result<DataType> { + match (info.logical_type(), info.converted_type()) { + (None, ConvertedType::NONE) => Ok(DataType::Int64), + ( + Some(LogicalType::Integer { + bit_width, + is_signed, + }), + _, + ) if bit_width == 64 => match is_signed { + true => Ok(DataType::Int64), + false => Ok(DataType::UInt64), + }, + (Some(LogicalType::Time { unit, .. }), _) => match unit { + ParquetTimeUnit::MILLIS(_) => { + Err(arrow_err!("Cannot create INT64 from MILLIS time unit",)) + } + ParquetTimeUnit::MICROS(_) => Ok(DataType::Time64(TimeUnit::Microsecond)), + ParquetTimeUnit::NANOS(_) => Ok(DataType::Time64(TimeUnit::Nanosecond)), + }, + ( + Some(LogicalType::Timestamp { + is_adjusted_to_u_t_c, + unit, + }), + _, + ) => Ok(DataType::Timestamp( + match unit { + ParquetTimeUnit::MILLIS(_) => TimeUnit::Millisecond, + ParquetTimeUnit::MICROS(_) => TimeUnit::Microsecond, + ParquetTimeUnit::NANOS(_) => TimeUnit::Nanosecond, + }, + if is_adjusted_to_u_t_c { + Some("UTC".to_string()) + } else { + None + }, + )), + (None, ConvertedType::INT_64) => Ok(DataType::Int64), + (None, ConvertedType::UINT_64) => Ok(DataType::UInt64), + (None, ConvertedType::TIME_MICROS) => Ok(DataType::Time64(TimeUnit::Microsecond)), + (None, ConvertedType::TIMESTAMP_MILLIS) => { + Ok(DataType::Timestamp(TimeUnit::Millisecond, None)) + } + (None, ConvertedType::TIMESTAMP_MICROS) => { + Ok(DataType::Timestamp(TimeUnit::Microsecond, None)) + } + (Some(LogicalType::Decimal { scale, precision }), _) => { + decimal_type(scale, precision) + } + (None, ConvertedType::DECIMAL) => decimal_type(scale, precision), + (logical, converted) => Err(arrow_err!( + "Unable to convert parquet INT64 logical type {:?} or converted type {}", + logical, + converted + )), + } +} + +fn from_byte_array(info: &BasicTypeInfo) -> Result<DataType> { + match (info.logical_type(), info.converted_type()) { + (Some(LogicalType::String), _) => Ok(DataType::Utf8), + (Some(LogicalType::Json), _) => Ok(DataType::Binary), + (Some(LogicalType::Bson), _) => Ok(DataType::Binary), + (Some(LogicalType::Enum), _) => Ok(DataType::Binary), + (None, ConvertedType::NONE) => Ok(DataType::Binary), + (None, ConvertedType::JSON) => Ok(DataType::Binary), + (None, ConvertedType::BSON) => Ok(DataType::Binary), + (None, ConvertedType::ENUM) => Ok(DataType::Binary), + (None, ConvertedType::UTF8) => Ok(DataType::Utf8), + (logical, converted) => Err(arrow_err!( + "Unable to convert parquet BYTE_ARRAY logical type {:?} or converted type {}", + logical, + converted + )), + } +} + +fn from_fixed_len_byte_array( + info: &BasicTypeInfo, + scale: i32, + precision: i32, + type_length: i32, +) -> Result<DataType> { + // TODO: This should check the type length for the decimal and interval types + match (info.logical_type(), info.converted_type()) { + (Some(LogicalType::Decimal { scale, precision }), _) => { + decimal_type(scale, precision) + } + (None, ConvertedType::DECIMAL) => decimal_type(scale, precision), + (None, ConvertedType::INTERVAL) => { + // There is currently no reliable way of determining which IntervalUnit + // to return. Thus without the original Arrow schema, the results + // would be incorrect if all 12 bytes of the interval are populated + Ok(DataType::Interval(IntervalUnit::DayTime)) + } + _ => Ok(DataType::FixedSizeBinary(type_length)), + } +} Review Comment: These type conversions are very well covered by the unit tests in schema.rs -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
