You are viewing a plain text version of this content. The canonical link for it is here.
Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/04/06 18:18:23 UTC
[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #2171: minor: Avoid per cell evaluation in Coalesce, use zip in CaseWhen
alamb commented on code in PR #2171:
URL: https://github.com/apache/arrow-datafusion/pull/2171#discussion_r844248002
##########
datafusion/physical-expr/src/conditional_expressions.rs:
##########
@@ -35,36 +33,51 @@ pub fn coalesce(args: &[ColumnarValue]) -> Result<ColumnarValue> {
)));
}
- let size = match args[0] {
- ColumnarValue::Array(ref a) => a.len(),
- ColumnarValue::Scalar(ref _s) => 1,
- };
- let mut res = new_null_array(&args[0].data_type(), size);
+ let return_type = args[0].data_type();
+ let mut return_array = args.iter().filter_map(|x| match x {
+ ColumnarValue::Array(array) => Some(array.len()),
+ _ => None,
+ });
+
+ if let Some(size) = return_array.next() {
+ // start with nulls as default output
+ let mut current_value = new_null_array(&return_type, size);
+ let mut remainder = BooleanArray::from(vec![true; size]);
- for column_value in args {
- for i in 0..size {
- match column_value {
- ColumnarValue::Array(array_ref) => {
- let curr_null_mask = compute::is_null(res.as_ref())?;
- let arr_not_null_mask = compute::is_not_null(array_ref)?;
- let bool_mask = compute::and(&curr_null_mask, &arr_not_null_mask)?;
- res = zip(&bool_mask, array_ref, &res)?;
+ for arg in args {
+ match arg {
+ ColumnarValue::Array(ref array) => {
+ let to_apply = and(&remainder, &is_not_null(array.as_ref())?)?;
+ current_value = zip(&to_apply, array, current_value.as_ref())?;
Review Comment:
👍
##########
datafusion/physical-expr/src/conditional_expressions.rs:
##########
@@ -35,36 +33,51 @@ pub fn coalesce(args: &[ColumnarValue]) -> Result<ColumnarValue> {
)));
}
- let size = match args[0] {
- ColumnarValue::Array(ref a) => a.len(),
- ColumnarValue::Scalar(ref _s) => 1,
- };
- let mut res = new_null_array(&args[0].data_type(), size);
+ let return_type = args[0].data_type();
+ let mut return_array = args.iter().filter_map(|x| match x {
+ ColumnarValue::Array(array) => Some(array.len()),
+ _ => None,
+ });
+
+ if let Some(size) = return_array.next() {
+ // start with nulls as default output
+ let mut current_value = new_null_array(&return_type, size);
+ let mut remainder = BooleanArray::from(vec![true; size]);
- for column_value in args {
- for i in 0..size {
- match column_value {
- ColumnarValue::Array(array_ref) => {
- let curr_null_mask = compute::is_null(res.as_ref())?;
- let arr_not_null_mask = compute::is_not_null(array_ref)?;
- let bool_mask = compute::and(&curr_null_mask, &arr_not_null_mask)?;
- res = zip(&bool_mask, array_ref, &res)?;
+ for arg in args {
+ match arg {
+ ColumnarValue::Array(ref array) => {
+ let to_apply = and(&remainder, &is_not_null(array.as_ref())?)?;
+ current_value = zip(&to_apply, array, current_value.as_ref())?;
+ remainder = and(&remainder, &is_null(array)?)?;
}
- ColumnarValue::Scalar(scalar) => {
- if !scalar.is_null() && res.is_null(i) {
- let vec: Vec<bool> =
- (0..size).into_iter().map(|j| j == i).collect();
- let bool_arr = BooleanArray::from(vec);
- res =
- zip(&bool_arr, scalar.to_array_of_size(size).as_ref(), &res)?;
+ ColumnarValue::Scalar(value) => {
+ if value.is_null() {
continue;
+ } else {
+ let last_value = value.to_array_of_size(size);
+ current_value =
+ zip(&remainder, &last_value, current_value.as_ref())?;
+ break;
Review Comment:
👍 early return on constant
##########
datafusion/physical-expr/src/expressions/case.rs:
##########
@@ -19,7 +19,8 @@ use std::{any::Any, sync::Arc};
use crate::expressions::try_cast;
use crate::PhysicalExpr;
-use arrow::array::{self, *};
+use arrow::array::*;
+use arrow::compute::kernels::zip::zip;
Review Comment:
Today I Learned: https://docs.rs/arrow/11.1.0/arrow/compute/kernels/zip/fn.zip.html ✅
##########
datafusion/physical-expr/src/conditional_expressions.rs:
##########
@@ -35,36 +33,51 @@ pub fn coalesce(args: &[ColumnarValue]) -> Result<ColumnarValue> {
)));
}
- let size = match args[0] {
- ColumnarValue::Array(ref a) => a.len(),
- ColumnarValue::Scalar(ref _s) => 1,
- };
- let mut res = new_null_array(&args[0].data_type(), size);
+ let return_type = args[0].data_type();
+ let mut return_array = args.iter().filter_map(|x| match x {
+ ColumnarValue::Array(array) => Some(array.len()),
+ _ => None,
+ });
+
+ if let Some(size) = return_array.next() {
+ // start with nulls as default output
+ let mut current_value = new_null_array(&return_type, size);
+ let mut remainder = BooleanArray::from(vec![true; size]);
- for column_value in args {
- for i in 0..size {
- match column_value {
- ColumnarValue::Array(array_ref) => {
- let curr_null_mask = compute::is_null(res.as_ref())?;
- let arr_not_null_mask = compute::is_not_null(array_ref)?;
- let bool_mask = compute::and(&curr_null_mask, &arr_not_null_mask)?;
- res = zip(&bool_mask, array_ref, &res)?;
+ for arg in args {
+ match arg {
+ ColumnarValue::Array(ref array) => {
+ let to_apply = and(&remainder, &is_not_null(array.as_ref())?)?;
+ current_value = zip(&to_apply, array, current_value.as_ref())?;
+ remainder = and(&remainder, &is_null(array)?)?;
}
- ColumnarValue::Scalar(scalar) => {
- if !scalar.is_null() && res.is_null(i) {
- let vec: Vec<bool> =
- (0..size).into_iter().map(|j| j == i).collect();
- let bool_arr = BooleanArray::from(vec);
- res =
- zip(&bool_arr, scalar.to_array_of_size(size).as_ref(), &res)?;
+ ColumnarValue::Scalar(value) => {
+ if value.is_null() {
continue;
+ } else {
+ let last_value = value.to_array_of_size(size);
+ current_value =
+ zip(&remainder, &last_value, current_value.as_ref())?;
+ break;
}
}
}
+ if remainder.iter().all(|x| x == Some(false)) {
Review Comment:
There are fancier / more optimized ways in the guts of the arrow-rs implementation for testing if a bitmask is entirely false, but maybe we can expose them if more optimization is needed
--
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: github-unsubscribe@arrow.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org