[GitHub] [arrow] jorgecarleitao commented on a change in pull request #8837: ARROW-10810: [Rust] Speed up comparison kernels

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

jorgecarleitao commented on a change in pull request #8837:
URL: https://github.com/apache/arrow/pull/8837#discussion_r536875918



##########
File path: rust/arrow/src/compute/kernels/comparison.rs
##########
@@ -68,9 +77,18 @@ macro_rules! compare_op {
 macro_rules! compare_op_scalar {
     ($left: expr, $right:expr, $op:expr) => {{
         let null_bit_buffer = $left.data().null_buffer().cloned();
-        let mut result = BooleanBufferBuilder::new($left.len());
+        let byte_capacity = bit_util::ceil($left.len(), 8);
+        let actual_capacity = bit_util::round_upto_multiple_of_64(byte_capacity);
+        let mut buffer = MutableBuffer::new(actual_capacity);
+        buffer.resize(byte_capacity);
+
+        let data = buffer.raw_data_mut();
         for i in 0..$left.len() {
-            result.append($op($left.value(i), $right))?;
+            if $op($left.value(i), $right) {
+                unsafe {
+                    bit_util::set_bit_raw(data, i);
+                }
+            }

Review comment:
       A side note: In general, if we are bypassing builders for speed, it can mean that builders are not a good abstraction, as they significantly impact performance.




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