[GitHub] [arrow] nevi-me commented on a change in pull request #8116: ARROW-9919: [Rust][DataFusion] Speedup math operations by 15%+

[GitBox <gi...@apache.org>]

nevi-me commented on a change in pull request #8116:
URL: https://github.com/apache/arrow/pull/8116#discussion_r483954060



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File path: rust/datafusion/src/physical_plan/math_expressions.rs
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@@ -19,23 +19,25 @@
 
 use crate::error::{ExecutionError, Result};
 
-use arrow::array::{Array, ArrayRef, Float32Array, Float64Array, Float64Builder};
+use arrow::array::{Array, ArrayRef, Float32Array, Float64Array};
 
 use arrow::datatypes::DataType;
 
 use std::sync::Arc;
 
 macro_rules! compute_op {
     ($ARRAY:expr, $FUNC:ident, $TYPE:ident) => {{
-        let mut builder = Float64Builder::new($ARRAY.len());
-        for i in 0..$ARRAY.len() {
-            if $ARRAY.is_null(i) {
-                builder.append_null()?;
-            } else {
-                builder.append_value($ARRAY.value(i).$FUNC() as f64)?;
-            }
-        }
-        Ok(Arc::new(builder.finish()))
+        let result: Float64Array = (0..$ARRAY.len())
+            .map(|i| {

Review comment:
       You could likely improve performance further by computing without checking nullity of array, and then building the array using the input bitmask.
   
   I'm away from home, so I don't have a PC to check with; but look at the pattern that most of the compute functions follow.
   
   Removing the if/else allows the compiler to vectorise the loop.




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