From 32344eff6ba6fe8106ad460f695e1fc5652aeec8 Mon Sep 17 00:00:00 2001
From: "Heres, Daniel" <danielheres@gmail.com>
Date: Sat, 5 Dec 2020 13:28:07 +0100
Subject: [PATCH 1/3] Comparison kernel speedup

---
 rust/arrow/src/compute/kernels/comparison.rs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/rust/arrow/src/compute/kernels/comparison.rs b/rust/arrow/src/compute/kernels/comparison.rs
index fd0bc7343f0..e8e529e9774 100644
--- a/rust/arrow/src/compute/kernels/comparison.rs
+++ b/rust/arrow/src/compute/kernels/comparison.rs
@@ -68,9 +68,14 @@ 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 mut result = MutableBuffer::new($left.len());
+        let data = result.raw_data_mut();
         for i in 0..$left.len() {
-            result.append($op($left.value(i), $right))?;
+            if $op($left.value(i), $right) {
+                unsafe {
+                    bit_util::set_bit_raw(data, i);
+                }
+            }
         }
 
         let data = ArrayData::new(
@@ -79,7 +84,7 @@ macro_rules! compare_op_scalar {
             None,
             null_bit_buffer,
             0,
-            vec![result.finish()],
+            vec![result.freeze()],
             vec![],
         );
         Ok(PrimitiveArray::<BooleanType>::from(Arc::new(data)))

From 55f382099749abf92c0767bd755b39c8f31f21e5 Mon Sep 17 00:00:00 2001
From: "Heres, Daniel" <danielheres@gmail.com>
Date: Sat, 5 Dec 2020 14:08:44 +0100
Subject: [PATCH 2/3] Make it hae same sizing as the bufferbuilder

---
 rust/arrow/src/compute/kernels/comparison.rs | 27 +++++++++++++++-----
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/rust/arrow/src/compute/kernels/comparison.rs b/rust/arrow/src/compute/kernels/comparison.rs
index e8e529e9774..f449e4ec700 100644
--- a/rust/arrow/src/compute/kernels/comparison.rs
+++ b/rust/arrow/src/compute/kernels/comparison.rs
@@ -47,9 +47,19 @@ macro_rules! compare_op {
         let null_bit_buffer =
             combine_option_bitmap($left.data_ref(), $right.data_ref(), $left.len())?;
 
-        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);
+        buffer.set_null_bits(0, actual_capacity);
+
+        let data = buffer.raw_data_mut();
         for i in 0..$left.len() {
-            result.append($op($left.value(i), $right.value(i)))?;
+            if $op($left.value(i), $right.value(i)) {
+                unsafe {
+                    bit_util::set_bit_raw(data, i);
+                }
+            }
         }
 
         let data = ArrayData::new(
@@ -58,7 +68,7 @@ macro_rules! compare_op {
             None,
             null_bit_buffer,
             0,
-            vec![result.finish()],
+            vec![buffer.freeze()],
             vec![],
         );
         Ok(PrimitiveArray::<BooleanType>::from(Arc::new(data)))
@@ -68,8 +78,13 @@ macro_rules! compare_op {
 macro_rules! compare_op_scalar {
     ($left: expr, $right:expr, $op:expr) => {{
         let null_bit_buffer = $left.data().null_buffer().cloned();
-        let mut result = MutableBuffer::new($left.len());
-        let data = result.raw_data_mut();
+        let byte_capacity = bit_util::ceil($left.len(), 8);
+        let actual_capacity = bit_util::round_upto_multiple_of_64(byte_capacity);
+        let mut buffer = MutableBuffer::new(actual_capacity);
+        buffer.resize(byte_capacity);
+
+        buffer.set_null_bits(0, actual_capacity);
+        let data = buffer.raw_data_mut();
         for i in 0..$left.len() {
             if $op($left.value(i), $right) {
                 unsafe {
@@ -84,7 +99,7 @@ macro_rules! compare_op_scalar {
             None,
             null_bit_buffer,
             0,
-            vec![result.freeze()],
+            vec![buffer.freeze()],
             vec![],
         );
         Ok(PrimitiveArray::<BooleanType>::from(Arc::new(data)))

From 62e71a2f1d9188160750056633a35c01a9c3579b Mon Sep 17 00:00:00 2001
From: "Heres, Daniel" <danielheres@gmail.com>
Date: Sat, 5 Dec 2020 14:20:45 +0100
Subject: [PATCH 3/3] Simplify

---
 rust/arrow/src/compute/kernels/comparison.rs | 2 --
 1 file changed, 2 deletions(-)

diff --git a/rust/arrow/src/compute/kernels/comparison.rs b/rust/arrow/src/compute/kernels/comparison.rs
index f449e4ec700..e708e12af35 100644
--- a/rust/arrow/src/compute/kernels/comparison.rs
+++ b/rust/arrow/src/compute/kernels/comparison.rs
@@ -51,7 +51,6 @@ macro_rules! compare_op {
         let actual_capacity = bit_util::round_upto_multiple_of_64(byte_capacity);
         let mut buffer = MutableBuffer::new(actual_capacity);
         buffer.resize(byte_capacity);
-        buffer.set_null_bits(0, actual_capacity);
 
         let data = buffer.raw_data_mut();
         for i in 0..$left.len() {
@@ -83,7 +82,6 @@ macro_rules! compare_op_scalar {
         let mut buffer = MutableBuffer::new(actual_capacity);
         buffer.resize(byte_capacity);
 
-        buffer.set_null_bits(0, actual_capacity);
         let data = buffer.raw_data_mut();
         for i in 0..$left.len() {
             if $op($left.value(i), $right) {