martin-g commented on code in PR #3619: URL: https://github.com/apache/datafusion-comet/pull/3619#discussion_r2889422328
########## native/spark-expr/src/math_funcs/internal/decimal_rescale_check.rs: ########## @@ -0,0 +1,431 @@ +// 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. + +//! Fused decimal rescale + overflow check expression. +//! +//! Replaces the pattern `CheckOverflow(Cast(expr, Decimal128(p2,s2)), Decimal128(p2,s2))` +//! with a single expression that rescales and validates precision in one pass. + +use arrow::array::{as_primitive_array, Array, ArrayRef, Decimal128Array}; +use arrow::datatypes::{DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::{DataFusionError, ScalarValue}; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::hash::Hash; +use std::{ + any::Any, + fmt::{Display, Formatter}, + sync::Arc, +}; + +/// A fused expression that rescales a Decimal128 value (changing scale) and checks +/// for precision overflow in a single pass. Replaces the two-step +/// `CheckOverflow(Cast(expr, Decimal128(p,s)))` pattern. +#[derive(Debug, Eq)] +pub struct DecimalRescaleCheckOverflow { + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, +} + +impl Hash for DecimalRescaleCheckOverflow { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.child.hash(state); + self.input_scale.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.fail_on_error.hash(state); + } +} + +impl PartialEq for DecimalRescaleCheckOverflow { + fn eq(&self, other: &Self) -> bool { + self.child.eq(&other.child) + && self.input_scale == other.input_scale + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.fail_on_error == other.fail_on_error + } +} + +impl DecimalRescaleCheckOverflow { + pub fn new( + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, + ) -> Self { + Self { + child, + input_scale, + output_precision, + output_scale, + fail_on_error, + } + } +} + +impl Display for DecimalRescaleCheckOverflow { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "DecimalRescaleCheckOverflow [child: {}, input_scale: {}, output: Decimal128({}, {}), fail_on_error: {}]", + self.child, self.input_scale, self.output_precision, self.output_scale, self.fail_on_error + ) + } +} + +/// Maximum absolute value for a given decimal precision: 10^p - 1. +#[inline] +fn precision_bound(precision: u8) -> i128 { + 10i128.pow(precision as u32) - 1 Review Comment: maybe add some validation that `precision` is <=38 ? or use checked_pow() and return a Result ########## native/spark-expr/src/math_funcs/wide_decimal_binary_expr.rs: ########## @@ -0,0 +1,502 @@ +// 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. + +//! Fused wide-decimal binary expression for Decimal128 add/sub/mul that may overflow. +//! +//! Instead of building a 4-node expression tree (Cast→BinaryExpr→Cast→Cast), this performs +//! i256 intermediate arithmetic in a single expression, producing only one output array. + +use crate::math_funcs::utils::get_precision_scale; +use crate::EvalMode; +use arrow::array::{Array, ArrayRef, AsArray, Decimal128Array}; +use arrow::datatypes::{i256, DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::Result; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::fmt::{Display, Formatter}; +use std::hash::Hash; +use std::{any::Any, sync::Arc}; + +/// The arithmetic operation to perform. +#[derive(Debug, Hash, PartialEq, Eq, Clone, Copy)] +pub enum WideDecimalOp { + Add, + Subtract, + Multiply, +} + +impl Display for WideDecimalOp { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + match self { + WideDecimalOp::Add => write!(f, "+"), + WideDecimalOp::Subtract => write!(f, "-"), + WideDecimalOp::Multiply => write!(f, "*"), + } + } +} + +/// A fused expression that evaluates Decimal128 add/sub/mul using i256 intermediate arithmetic, +/// applies scale adjustment with HALF_UP rounding, checks precision bounds, and outputs +/// a single Decimal128 array. +#[derive(Debug, Eq)] +pub struct WideDecimalBinaryExpr { + left: Arc<dyn PhysicalExpr>, + right: Arc<dyn PhysicalExpr>, + op: WideDecimalOp, + output_precision: u8, + output_scale: i8, + eval_mode: EvalMode, +} + +impl Hash for WideDecimalBinaryExpr { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.left.hash(state); + self.right.hash(state); + self.op.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.eval_mode.hash(state); + } +} + +impl PartialEq for WideDecimalBinaryExpr { + fn eq(&self, other: &Self) -> bool { + self.left.eq(&other.left) + && self.right.eq(&other.right) + && self.op == other.op + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.eval_mode == other.eval_mode + } +} + +impl WideDecimalBinaryExpr { + pub fn new( + left: Arc<dyn PhysicalExpr>, + right: Arc<dyn PhysicalExpr>, + op: WideDecimalOp, + output_precision: u8, + output_scale: i8, + eval_mode: EvalMode, + ) -> Self { + Self { + left, + right, + op, + output_precision, + output_scale, + eval_mode, + } + } +} + +impl Display for WideDecimalBinaryExpr { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "WideDecimalBinaryExpr [{} {} {}, output: Decimal128({}, {})]", + self.left, self.op, self.right, self.output_precision, self.output_scale + ) + } +} + +/// Compute `value / divisor` with HALF_UP rounding. +#[inline] +fn div_round_half_up(value: i256, divisor: i256) -> i256 { + let (quot, rem) = (value / divisor, value % divisor); + // HALF_UP: if |remainder| * 2 >= |divisor|, round away from zero + let abs_rem_x2 = if rem < i256::ZERO { + rem.wrapping_neg() + } else { + rem + } + .wrapping_mul(i256::from_i128(2)); + let abs_divisor = if divisor < i256::ZERO { + divisor.wrapping_neg() + } else { + divisor + }; + if abs_rem_x2 >= abs_divisor { + if (value < i256::ZERO) != (divisor < i256::ZERO) { + quot.wrapping_sub(i256::ONE) + } else { + quot.wrapping_add(i256::ONE) + } + } else { + quot + } +} + +/// i256 constant for 10. +const I256_TEN: i256 = i256::from_i128(10); + +/// Compute 10^exp as i256. +#[inline] +fn i256_pow10(exp: u32) -> i256 { + let mut result = i256::ONE; + for _ in 0..exp { + result = result.wrapping_mul(I256_TEN); + } + result +} + +/// Maximum i128 value for a given decimal precision (1-indexed). +/// precision p allows values in [-10^p + 1, 10^p - 1]. +#[inline] +fn max_for_precision(precision: u8) -> i256 { + i256_pow10(precision as u32).wrapping_sub(i256::ONE) +} + +impl PhysicalExpr for WideDecimalBinaryExpr { + fn as_any(&self) -> &dyn Any { + self + } + + fn data_type(&self, _input_schema: &Schema) -> Result<DataType> { + Ok(DataType::Decimal128( + self.output_precision, + self.output_scale, + )) + } + + fn nullable(&self, _input_schema: &Schema) -> Result<bool> { + Ok(true) + } + + fn evaluate(&self, batch: &RecordBatch) -> Result<ColumnarValue> { + let left_val = self.left.evaluate(batch)?; + let right_val = self.right.evaluate(batch)?; + + let (left_arr, right_arr): (ArrayRef, ArrayRef) = match (&left_val, &right_val) { + (ColumnarValue::Array(l), ColumnarValue::Array(r)) => (Arc::clone(l), Arc::clone(r)), + (ColumnarValue::Scalar(l), ColumnarValue::Array(r)) => { + (l.to_array_of_size(r.len())?, Arc::clone(r)) + } + (ColumnarValue::Array(l), ColumnarValue::Scalar(r)) => { + (Arc::clone(l), r.to_array_of_size(l.len())?) + } + (ColumnarValue::Scalar(l), ColumnarValue::Scalar(r)) => (l.to_array()?, r.to_array()?), + }; + + let left = left_arr.as_primitive::<Decimal128Type>(); + let right = right_arr.as_primitive::<Decimal128Type>(); + let (_p1, s1) = get_precision_scale(left.data_type()); + let (_p2, s2) = get_precision_scale(right.data_type()); + + let p_out = self.output_precision; + let s_out = self.output_scale; + let op = self.op; + let eval_mode = self.eval_mode; + + let bound = max_for_precision(p_out); + let neg_bound = i256::ZERO.wrapping_sub(bound); + + let result: Decimal128Array = match op { + WideDecimalOp::Add | WideDecimalOp::Subtract => { + let max_scale = std::cmp::max(s1, s2); + let l_scale_up = i256_pow10((max_scale - s1) as u32); + let r_scale_up = i256_pow10((max_scale - s2) as u32); + let need_rescale = s_out < max_scale; + let rescale_divisor = if need_rescale { + i256_pow10((max_scale - s_out) as u32) + } else { + i256::ONE + }; + + arrow::compute::kernels::arity::try_binary(left, right, |l, r| { + let l256 = i256::from_i128(l).wrapping_mul(l_scale_up); + let r256 = i256::from_i128(r).wrapping_mul(r_scale_up); + let raw = match op { + WideDecimalOp::Add => l256.wrapping_add(r256), + WideDecimalOp::Subtract => l256.wrapping_sub(r256), + _ => unreachable!(), + }; + let result = if need_rescale { + div_round_half_up(raw, rescale_divisor) + } else { + raw + }; + check_overflow_and_convert(result, bound, neg_bound, eval_mode) + })? + } + WideDecimalOp::Multiply => { + let natural_scale = s1 + s2; + let need_rescale = s_out < natural_scale; + let rescale_divisor = if need_rescale { + i256_pow10((natural_scale - s_out) as u32) + } else { + i256::ONE + }; + + arrow::compute::kernels::arity::try_binary(left, right, |l, r| { + let raw = i256::from_i128(l).wrapping_mul(i256::from_i128(r)); + let result = if need_rescale { + div_round_half_up(raw, rescale_divisor) + } else { + raw + }; + check_overflow_and_convert(result, bound, neg_bound, eval_mode) + })? + } + }; + + let result = if eval_mode != EvalMode::Ansi { + result.null_if_overflow_precision(p_out) + } else { + result + }; + let result = result.with_data_type(DataType::Decimal128(p_out, s_out)); + Ok(ColumnarValue::Array(Arc::new(result))) + } + + fn children(&self) -> Vec<&Arc<dyn PhysicalExpr>> { + vec![&self.left, &self.right] + } + + fn with_new_children( + self: Arc<Self>, + children: Vec<Arc<dyn PhysicalExpr>>, + ) -> Result<Arc<dyn PhysicalExpr>> { Review Comment: ```suggestion ) -> Result<Arc<dyn PhysicalExpr>> { if children.len() != 2 { return Err(DataFusionError::Internal(format!( "WideDecimalBinaryExpr expects 2 children, got {}", children.len() ))); } ``` ########## native/core/src/execution/planner.rs: ########## @@ -376,10 +377,37 @@ impl PhysicalPlanner { ))) } ExprStruct::CheckOverflow(expr) => { - let child = self.create_expr(expr.child.as_ref().unwrap(), input_schema)?; + let child = + self.create_expr(expr.child.as_ref().unwrap(), Arc::clone(&input_schema))?; let data_type = to_arrow_datatype(expr.datatype.as_ref().unwrap()); let fail_on_error = expr.fail_on_error; + // WideDecimalBinaryExpr already handles overflow — skip redundant check + if child + .as_any() + .downcast_ref::<WideDecimalBinaryExpr>() + .is_some() + { + return Ok(child); + } + + // Fuse Cast(Decimal128→Decimal128) + CheckOverflow into single rescale+check + if let Some(cast) = child.as_any().downcast_ref::<Cast>() { Review Comment: Should this also check that the Cast's precision/scale match the output's p/s before fusing ? ########## native/core/src/execution/planner.rs: ########## @@ -674,31 +702,31 @@ impl PhysicalPlanner { ) { ( DataFusionOperator::Plus | DataFusionOperator::Minus | DataFusionOperator::Multiply, - Ok(DataType::Decimal128(p1, s1)), - Ok(DataType::Decimal128(p2, s2)), + Ok(DataType::Decimal128(_p1, _s1)), Review Comment: What is the reason to use `_` prefix ? The variables are used ########## native/spark-expr/src/math_funcs/internal/decimal_rescale_check.rs: ########## @@ -0,0 +1,431 @@ +// 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. + +//! Fused decimal rescale + overflow check expression. +//! +//! Replaces the pattern `CheckOverflow(Cast(expr, Decimal128(p2,s2)), Decimal128(p2,s2))` +//! with a single expression that rescales and validates precision in one pass. + +use arrow::array::{as_primitive_array, Array, ArrayRef, Decimal128Array}; +use arrow::datatypes::{DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::{DataFusionError, ScalarValue}; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::hash::Hash; +use std::{ + any::Any, + fmt::{Display, Formatter}, + sync::Arc, +}; + +/// A fused expression that rescales a Decimal128 value (changing scale) and checks +/// for precision overflow in a single pass. Replaces the two-step +/// `CheckOverflow(Cast(expr, Decimal128(p,s)))` pattern. +#[derive(Debug, Eq)] +pub struct DecimalRescaleCheckOverflow { + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, +} + +impl Hash for DecimalRescaleCheckOverflow { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.child.hash(state); + self.input_scale.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.fail_on_error.hash(state); + } +} + +impl PartialEq for DecimalRescaleCheckOverflow { + fn eq(&self, other: &Self) -> bool { + self.child.eq(&other.child) + && self.input_scale == other.input_scale + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.fail_on_error == other.fail_on_error + } +} + +impl DecimalRescaleCheckOverflow { + pub fn new( + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, + ) -> Self { + Self { + child, + input_scale, + output_precision, + output_scale, + fail_on_error, + } + } +} + +impl Display for DecimalRescaleCheckOverflow { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "DecimalRescaleCheckOverflow [child: {}, input_scale: {}, output: Decimal128({}, {}), fail_on_error: {}]", + self.child, self.input_scale, self.output_precision, self.output_scale, self.fail_on_error + ) + } +} + +/// Maximum absolute value for a given decimal precision: 10^p - 1. +#[inline] +fn precision_bound(precision: u8) -> i128 { + 10i128.pow(precision as u32) - 1 +} + +/// Rescale a single i128 value by the given delta (output_scale - input_scale) +/// and check precision bounds. Returns `Ok(value)` or `Ok(i128::MAX)` as sentinel +/// for overflow in legacy mode, or `Err` in ANSI mode. +#[inline] +fn rescale_and_check( + value: i128, + delta: i8, + scale_factor: i128, + bound: i128, + fail_on_error: bool, +) -> Result<i128, ArrowError> { + let rescaled = if delta > 0 { + // Scale up: multiply. Check for overflow. + match value.checked_mul(scale_factor) { + Some(v) => v, + None => { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow during rescale".to_string(), + )); + } + return Ok(i128::MAX); // sentinel + } + } + } else if delta < 0 { + // Scale down with HALF_UP rounding + // divisor = 10^(-delta), half = divisor / 2 + let divisor = scale_factor; // already 10^abs(delta) + let half = divisor / 2; + let sign = if value < 0 { -1i128 } else { 1i128 }; + (value + sign * half) / divisor + } else { + value + }; + + // Precision check + if rescaled.abs() > bound { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow: value does not fit in precision".to_string(), + )); + } + Ok(i128::MAX) // sentinel for null_if_overflow_precision + } else { + Ok(rescaled) + } +} + +impl PhysicalExpr for DecimalRescaleCheckOverflow { + fn as_any(&self) -> &dyn Any { + self + } + + fn fmt_sql(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + Display::fmt(self, f) + } + + fn data_type(&self, _: &Schema) -> datafusion::common::Result<DataType> { + Ok(DataType::Decimal128( + self.output_precision, + self.output_scale, + )) + } + + fn nullable(&self, _: &Schema) -> datafusion::common::Result<bool> { + Ok(true) + } + + fn evaluate(&self, batch: &RecordBatch) -> datafusion::common::Result<ColumnarValue> { + let arg = self.child.evaluate(batch)?; + let delta = self.output_scale - self.input_scale; Review Comment: The scales could be negative. Let's say `output_scale=38` ( the maximum supported one) and `input_scale=-1`, the `delta=39`. This will lead to an error below at `10i128.pow(abs_delta as u32);` ########## native/spark-expr/src/math_funcs/wide_decimal_binary_expr.rs: ########## @@ -0,0 +1,502 @@ +// 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. + +//! Fused wide-decimal binary expression for Decimal128 add/sub/mul that may overflow. +//! +//! Instead of building a 4-node expression tree (Cast→BinaryExpr→Cast→Cast), this performs +//! i256 intermediate arithmetic in a single expression, producing only one output array. + +use crate::math_funcs::utils::get_precision_scale; +use crate::EvalMode; +use arrow::array::{Array, ArrayRef, AsArray, Decimal128Array}; +use arrow::datatypes::{i256, DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::Result; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::fmt::{Display, Formatter}; +use std::hash::Hash; +use std::{any::Any, sync::Arc}; + +/// The arithmetic operation to perform. +#[derive(Debug, Hash, PartialEq, Eq, Clone, Copy)] +pub enum WideDecimalOp { + Add, + Subtract, + Multiply, +} + +impl Display for WideDecimalOp { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + match self { + WideDecimalOp::Add => write!(f, "+"), + WideDecimalOp::Subtract => write!(f, "-"), + WideDecimalOp::Multiply => write!(f, "*"), + } + } +} + +/// A fused expression that evaluates Decimal128 add/sub/mul using i256 intermediate arithmetic, +/// applies scale adjustment with HALF_UP rounding, checks precision bounds, and outputs +/// a single Decimal128 array. +#[derive(Debug, Eq)] +pub struct WideDecimalBinaryExpr { + left: Arc<dyn PhysicalExpr>, + right: Arc<dyn PhysicalExpr>, + op: WideDecimalOp, + output_precision: u8, + output_scale: i8, + eval_mode: EvalMode, +} + +impl Hash for WideDecimalBinaryExpr { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.left.hash(state); + self.right.hash(state); + self.op.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.eval_mode.hash(state); + } +} + +impl PartialEq for WideDecimalBinaryExpr { + fn eq(&self, other: &Self) -> bool { + self.left.eq(&other.left) + && self.right.eq(&other.right) + && self.op == other.op + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.eval_mode == other.eval_mode + } +} + +impl WideDecimalBinaryExpr { + pub fn new( + left: Arc<dyn PhysicalExpr>, + right: Arc<dyn PhysicalExpr>, + op: WideDecimalOp, + output_precision: u8, + output_scale: i8, + eval_mode: EvalMode, + ) -> Self { + Self { + left, + right, + op, + output_precision, + output_scale, + eval_mode, + } + } +} + +impl Display for WideDecimalBinaryExpr { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "WideDecimalBinaryExpr [{} {} {}, output: Decimal128({}, {})]", + self.left, self.op, self.right, self.output_precision, self.output_scale + ) + } +} + +/// Compute `value / divisor` with HALF_UP rounding. +#[inline] +fn div_round_half_up(value: i256, divisor: i256) -> i256 { + let (quot, rem) = (value / divisor, value % divisor); + // HALF_UP: if |remainder| * 2 >= |divisor|, round away from zero + let abs_rem_x2 = if rem < i256::ZERO { + rem.wrapping_neg() + } else { + rem + } + .wrapping_mul(i256::from_i128(2)); + let abs_divisor = if divisor < i256::ZERO { + divisor.wrapping_neg() + } else { + divisor + }; + if abs_rem_x2 >= abs_divisor { + if (value < i256::ZERO) != (divisor < i256::ZERO) { + quot.wrapping_sub(i256::ONE) + } else { + quot.wrapping_add(i256::ONE) + } + } else { + quot + } +} + +/// i256 constant for 10. +const I256_TEN: i256 = i256::from_i128(10); + +/// Compute 10^exp as i256. +#[inline] +fn i256_pow10(exp: u32) -> i256 { Review Comment: extreme case: `exp>77` will overflow ########## native/spark-expr/src/math_funcs/internal/decimal_rescale_check.rs: ########## @@ -0,0 +1,431 @@ +// 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. + +//! Fused decimal rescale + overflow check expression. +//! +//! Replaces the pattern `CheckOverflow(Cast(expr, Decimal128(p2,s2)), Decimal128(p2,s2))` +//! with a single expression that rescales and validates precision in one pass. + +use arrow::array::{as_primitive_array, Array, ArrayRef, Decimal128Array}; +use arrow::datatypes::{DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::{DataFusionError, ScalarValue}; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::hash::Hash; +use std::{ + any::Any, + fmt::{Display, Formatter}, + sync::Arc, +}; + +/// A fused expression that rescales a Decimal128 value (changing scale) and checks +/// for precision overflow in a single pass. Replaces the two-step +/// `CheckOverflow(Cast(expr, Decimal128(p,s)))` pattern. +#[derive(Debug, Eq)] +pub struct DecimalRescaleCheckOverflow { + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, +} + +impl Hash for DecimalRescaleCheckOverflow { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.child.hash(state); + self.input_scale.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.fail_on_error.hash(state); + } +} + +impl PartialEq for DecimalRescaleCheckOverflow { + fn eq(&self, other: &Self) -> bool { + self.child.eq(&other.child) + && self.input_scale == other.input_scale + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.fail_on_error == other.fail_on_error + } +} + +impl DecimalRescaleCheckOverflow { + pub fn new( + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, + ) -> Self { + Self { + child, + input_scale, + output_precision, + output_scale, + fail_on_error, + } + } +} + +impl Display for DecimalRescaleCheckOverflow { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "DecimalRescaleCheckOverflow [child: {}, input_scale: {}, output: Decimal128({}, {}), fail_on_error: {}]", + self.child, self.input_scale, self.output_precision, self.output_scale, self.fail_on_error + ) + } +} + +/// Maximum absolute value for a given decimal precision: 10^p - 1. +#[inline] +fn precision_bound(precision: u8) -> i128 { + 10i128.pow(precision as u32) - 1 +} + +/// Rescale a single i128 value by the given delta (output_scale - input_scale) +/// and check precision bounds. Returns `Ok(value)` or `Ok(i128::MAX)` as sentinel +/// for overflow in legacy mode, or `Err` in ANSI mode. +#[inline] +fn rescale_and_check( + value: i128, + delta: i8, + scale_factor: i128, + bound: i128, + fail_on_error: bool, +) -> Result<i128, ArrowError> { + let rescaled = if delta > 0 { + // Scale up: multiply. Check for overflow. + match value.checked_mul(scale_factor) { + Some(v) => v, + None => { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow during rescale".to_string(), + )); + } + return Ok(i128::MAX); // sentinel + } + } + } else if delta < 0 { + // Scale down with HALF_UP rounding + // divisor = 10^(-delta), half = divisor / 2 + let divisor = scale_factor; // already 10^abs(delta) + let half = divisor / 2; + let sign = if value < 0 { -1i128 } else { 1i128 }; + (value + sign * half) / divisor + } else { + value + }; + + // Precision check + if rescaled.abs() > bound { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow: value does not fit in precision".to_string(), + )); + } + Ok(i128::MAX) // sentinel for null_if_overflow_precision + } else { + Ok(rescaled) + } +} + +impl PhysicalExpr for DecimalRescaleCheckOverflow { + fn as_any(&self) -> &dyn Any { + self + } + + fn fmt_sql(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + Display::fmt(self, f) + } + + fn data_type(&self, _: &Schema) -> datafusion::common::Result<DataType> { + Ok(DataType::Decimal128( + self.output_precision, + self.output_scale, + )) + } + + fn nullable(&self, _: &Schema) -> datafusion::common::Result<bool> { + Ok(true) + } + + fn evaluate(&self, batch: &RecordBatch) -> datafusion::common::Result<ColumnarValue> { + let arg = self.child.evaluate(batch)?; + let delta = self.output_scale - self.input_scale; + let abs_delta = delta.unsigned_abs(); + let scale_factor = 10i128.pow(abs_delta as u32); + let bound = precision_bound(self.output_precision); + let fail_on_error = self.fail_on_error; + let p_out = self.output_precision; + let s_out = self.output_scale; + + match arg { + ColumnarValue::Array(array) + if matches!(array.data_type(), DataType::Decimal128(_, _)) => + { + let decimal_array = as_primitive_array::<Decimal128Type>(&array); + + let result: Decimal128Array = + arrow::compute::kernels::arity::try_unary(decimal_array, |value| { + rescale_and_check(value, delta, scale_factor, bound, fail_on_error) + })?; + + let result = if !fail_on_error { + result.null_if_overflow_precision(p_out) + } else { + result + }; + + let result = result + .with_precision_and_scale(p_out, s_out) + .map(|a| Arc::new(a) as ArrayRef)?; + + Ok(ColumnarValue::Array(result)) + } + ColumnarValue::Scalar(ScalarValue::Decimal128(v, _precision, _scale)) => { + let new_v = v.and_then(|val| { + rescale_and_check(val, delta, scale_factor, bound, fail_on_error) + .ok() Review Comment: If `fail_on_error=true` then this `.ok()` will convert it to `None` and hide the error ########## native/spark-expr/src/math_funcs/internal/decimal_rescale_check.rs: ########## @@ -0,0 +1,431 @@ +// 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. + +//! Fused decimal rescale + overflow check expression. +//! +//! Replaces the pattern `CheckOverflow(Cast(expr, Decimal128(p2,s2)), Decimal128(p2,s2))` +//! with a single expression that rescales and validates precision in one pass. + +use arrow::array::{as_primitive_array, Array, ArrayRef, Decimal128Array}; +use arrow::datatypes::{DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::{DataFusionError, ScalarValue}; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::hash::Hash; +use std::{ + any::Any, + fmt::{Display, Formatter}, + sync::Arc, +}; + +/// A fused expression that rescales a Decimal128 value (changing scale) and checks +/// for precision overflow in a single pass. Replaces the two-step +/// `CheckOverflow(Cast(expr, Decimal128(p,s)))` pattern. +#[derive(Debug, Eq)] +pub struct DecimalRescaleCheckOverflow { + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, +} + +impl Hash for DecimalRescaleCheckOverflow { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.child.hash(state); + self.input_scale.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.fail_on_error.hash(state); + } +} + +impl PartialEq for DecimalRescaleCheckOverflow { + fn eq(&self, other: &Self) -> bool { + self.child.eq(&other.child) + && self.input_scale == other.input_scale + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.fail_on_error == other.fail_on_error + } +} + +impl DecimalRescaleCheckOverflow { + pub fn new( + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, + ) -> Self { + Self { + child, + input_scale, + output_precision, + output_scale, + fail_on_error, + } + } +} + +impl Display for DecimalRescaleCheckOverflow { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "DecimalRescaleCheckOverflow [child: {}, input_scale: {}, output: Decimal128({}, {}), fail_on_error: {}]", + self.child, self.input_scale, self.output_precision, self.output_scale, self.fail_on_error + ) + } +} + +/// Maximum absolute value for a given decimal precision: 10^p - 1. +#[inline] +fn precision_bound(precision: u8) -> i128 { + 10i128.pow(precision as u32) - 1 +} + +/// Rescale a single i128 value by the given delta (output_scale - input_scale) +/// and check precision bounds. Returns `Ok(value)` or `Ok(i128::MAX)` as sentinel +/// for overflow in legacy mode, or `Err` in ANSI mode. +#[inline] +fn rescale_and_check( + value: i128, + delta: i8, + scale_factor: i128, + bound: i128, + fail_on_error: bool, +) -> Result<i128, ArrowError> { + let rescaled = if delta > 0 { + // Scale up: multiply. Check for overflow. + match value.checked_mul(scale_factor) { + Some(v) => v, + None => { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow during rescale".to_string(), + )); + } + return Ok(i128::MAX); // sentinel + } + } + } else if delta < 0 { + // Scale down with HALF_UP rounding + // divisor = 10^(-delta), half = divisor / 2 + let divisor = scale_factor; // already 10^abs(delta) + let half = divisor / 2; + let sign = if value < 0 { -1i128 } else { 1i128 }; + (value + sign * half) / divisor + } else { + value + }; + + // Precision check + if rescaled.abs() > bound { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow: value does not fit in precision".to_string(), + )); + } + Ok(i128::MAX) // sentinel for null_if_overflow_precision + } else { + Ok(rescaled) + } +} + +impl PhysicalExpr for DecimalRescaleCheckOverflow { + fn as_any(&self) -> &dyn Any { + self + } + + fn fmt_sql(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + Display::fmt(self, f) + } + + fn data_type(&self, _: &Schema) -> datafusion::common::Result<DataType> { + Ok(DataType::Decimal128( + self.output_precision, + self.output_scale, + )) + } + + fn nullable(&self, _: &Schema) -> datafusion::common::Result<bool> { + Ok(true) + } + + fn evaluate(&self, batch: &RecordBatch) -> datafusion::common::Result<ColumnarValue> { + let arg = self.child.evaluate(batch)?; + let delta = self.output_scale - self.input_scale; + let abs_delta = delta.unsigned_abs(); + let scale_factor = 10i128.pow(abs_delta as u32); + let bound = precision_bound(self.output_precision); + let fail_on_error = self.fail_on_error; + let p_out = self.output_precision; + let s_out = self.output_scale; + + match arg { + ColumnarValue::Array(array) + if matches!(array.data_type(), DataType::Decimal128(_, _)) => + { + let decimal_array = as_primitive_array::<Decimal128Type>(&array); + + let result: Decimal128Array = + arrow::compute::kernels::arity::try_unary(decimal_array, |value| { + rescale_and_check(value, delta, scale_factor, bound, fail_on_error) + })?; + + let result = if !fail_on_error { + result.null_if_overflow_precision(p_out) + } else { + result + }; + + let result = result + .with_precision_and_scale(p_out, s_out) + .map(|a| Arc::new(a) as ArrayRef)?; + + Ok(ColumnarValue::Array(result)) + } + ColumnarValue::Scalar(ScalarValue::Decimal128(v, _precision, _scale)) => { + let new_v = v.and_then(|val| { + rescale_and_check(val, delta, scale_factor, bound, fail_on_error) + .ok() + .and_then(|r| if r == i128::MAX { None } else { Some(r) }) + }); + Ok(ColumnarValue::Scalar(ScalarValue::Decimal128( + new_v, p_out, s_out, + ))) + } + v => Err(DataFusionError::Execution(format!( + "DecimalRescaleCheckOverflow expects Decimal128, but found {v:?}" + ))), + } + } + + fn children(&self) -> Vec<&Arc<dyn PhysicalExpr>> { + vec![&self.child] + } + + fn with_new_children( + self: Arc<Self>, + children: Vec<Arc<dyn PhysicalExpr>>, + ) -> datafusion::common::Result<Arc<dyn PhysicalExpr>> { Review Comment: ```suggestion ) -> datafusion::common::Result<Arc<dyn PhysicalExpr>> { if children.len() != 1 { return Err(DataFusionError::Internal(format!( "DecimalRescaleCheckOverflow expects 1 child, got {}", children.len() ))); } ``` ########## native/spark-expr/src/math_funcs/internal/decimal_rescale_check.rs: ########## @@ -0,0 +1,431 @@ +// 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. + +//! Fused decimal rescale + overflow check expression. +//! +//! Replaces the pattern `CheckOverflow(Cast(expr, Decimal128(p2,s2)), Decimal128(p2,s2))` +//! with a single expression that rescales and validates precision in one pass. + +use arrow::array::{as_primitive_array, Array, ArrayRef, Decimal128Array}; +use arrow::datatypes::{DataType, Decimal128Type, Schema}; +use arrow::error::ArrowError; +use arrow::record_batch::RecordBatch; +use datafusion::common::{DataFusionError, ScalarValue}; +use datafusion::logical_expr::ColumnarValue; +use datafusion::physical_expr::PhysicalExpr; +use std::hash::Hash; +use std::{ + any::Any, + fmt::{Display, Formatter}, + sync::Arc, +}; + +/// A fused expression that rescales a Decimal128 value (changing scale) and checks +/// for precision overflow in a single pass. Replaces the two-step +/// `CheckOverflow(Cast(expr, Decimal128(p,s)))` pattern. +#[derive(Debug, Eq)] +pub struct DecimalRescaleCheckOverflow { + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, +} + +impl Hash for DecimalRescaleCheckOverflow { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + self.child.hash(state); + self.input_scale.hash(state); + self.output_precision.hash(state); + self.output_scale.hash(state); + self.fail_on_error.hash(state); + } +} + +impl PartialEq for DecimalRescaleCheckOverflow { + fn eq(&self, other: &Self) -> bool { + self.child.eq(&other.child) + && self.input_scale == other.input_scale + && self.output_precision == other.output_precision + && self.output_scale == other.output_scale + && self.fail_on_error == other.fail_on_error + } +} + +impl DecimalRescaleCheckOverflow { + pub fn new( + child: Arc<dyn PhysicalExpr>, + input_scale: i8, + output_precision: u8, + output_scale: i8, + fail_on_error: bool, + ) -> Self { + Self { + child, + input_scale, + output_precision, + output_scale, + fail_on_error, + } + } +} + +impl Display for DecimalRescaleCheckOverflow { + fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { + write!( + f, + "DecimalRescaleCheckOverflow [child: {}, input_scale: {}, output: Decimal128({}, {}), fail_on_error: {}]", + self.child, self.input_scale, self.output_precision, self.output_scale, self.fail_on_error + ) + } +} + +/// Maximum absolute value for a given decimal precision: 10^p - 1. +#[inline] +fn precision_bound(precision: u8) -> i128 { + 10i128.pow(precision as u32) - 1 +} + +/// Rescale a single i128 value by the given delta (output_scale - input_scale) +/// and check precision bounds. Returns `Ok(value)` or `Ok(i128::MAX)` as sentinel +/// for overflow in legacy mode, or `Err` in ANSI mode. +#[inline] +fn rescale_and_check( + value: i128, + delta: i8, + scale_factor: i128, + bound: i128, + fail_on_error: bool, +) -> Result<i128, ArrowError> { + let rescaled = if delta > 0 { + // Scale up: multiply. Check for overflow. + match value.checked_mul(scale_factor) { + Some(v) => v, + None => { + if fail_on_error { + return Err(ArrowError::ComputeError( + "Decimal overflow during rescale".to_string(), + )); + } + return Ok(i128::MAX); // sentinel + } + } + } else if delta < 0 { + // Scale down with HALF_UP rounding + // divisor = 10^(-delta), half = divisor / 2 + let divisor = scale_factor; // already 10^abs(delta) + let half = divisor / 2; + let sign = if value < 0 { -1i128 } else { 1i128 }; Review Comment: ```suggestion let sign = value.signum(); ``` -- This is an automated message from the Apache Git Service. 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