From 8af989e2e52aa6ecb2ed65b60923949d355c88e9 Mon Sep 17 00:00:00 2001
From: Raz Luvaton <16746759+rluvaton@users.noreply.github.com>
Date: Wed, 5 Nov 2025 00:35:01 +0200
Subject: [PATCH 1/2] perf: override `ArrayIter` default impl for `nth`,
 `nth_back`, `last` and `count`

---
 arrow-array/src/iterator.rs | 49 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/arrow-array/src/iterator.rs b/arrow-array/src/iterator.rs
index e72b259ef049..05e0d410aa96 100644
--- a/arrow-array/src/iterator.rs
+++ b/arrow-array/src/iterator.rs
@@ -56,7 +56,7 @@ impl<T: ArrayAccessor> ArrayIter<T> {
     /// create a new iterator
     pub fn new(array: T) -> Self {
         let len = array.len();
-        let logical_nulls = array.logical_nulls();
+        let logical_nulls = array.logical_nulls().filter(|x| x.null_count() > 0);
         ArrayIter {
             array,
             logical_nulls,
@@ -102,6 +102,35 @@ impl<T: ArrayAccessor> Iterator for ArrayIter<T> {
             Some(self.current_end - self.current),
         )
     }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        // Check if we can advance to the desired offset
+        match self.current.checked_add(n) {
+            // Yes, and still within bounds
+            Some(new_current) if new_current < self.current_end => {
+                self.current = new_current;
+            }
+
+            // Either overflow or would exceed current_end
+            _ => {
+                self.current = self.current_end;
+                return None;
+            }
+        }
+
+        self.next()
+    }
+
+    fn last(mut self) -> Option<Self::Item> {
+        self.next_back()
+    }
+
+    fn count(self) -> usize
+    where
+        Self: Sized,
+    {
+        self.len()
+    }
 }
 
 impl<T: ArrayAccessor> DoubleEndedIterator for ArrayIter<T> {
@@ -122,6 +151,24 @@ impl<T: ArrayAccessor> DoubleEndedIterator for ArrayIter<T> {
             })
         }
     }
+
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
+        // Check if we advance to the one before the desired offset
+        match self.current_end.checked_sub(n) {
+            // Yes, and still within bounds
+            Some(new_offset) if self.current < new_offset => {
+                self.current_end = new_offset;
+            }
+
+            // Either underflow or would exceed current
+            _ => {
+                self.current = self.current_end;
+                return None;
+            }
+        }
+
+        self.next_back()
+    }
 }
 
 /// all arrays have known size.

From 565fd1f6c5e3667d730dd9eb3592a07425bbc012 Mon Sep 17 00:00:00 2001
From: Raz Luvaton <16746759+rluvaton@users.noreply.github.com>
Date: Wed, 5 Nov 2025 00:48:45 +0200
Subject: [PATCH 2/2] add inline to match rust impl

---
 arrow-array/src/iterator.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arrow-array/src/iterator.rs b/arrow-array/src/iterator.rs
index 05e0d410aa96..c281231a2e79 100644
--- a/arrow-array/src/iterator.rs
+++ b/arrow-array/src/iterator.rs
@@ -103,6 +103,7 @@ impl<T: ArrayAccessor> Iterator for ArrayIter<T> {
         )
     }
 
+    #[inline]
     fn nth(&mut self, n: usize) -> Option<Self::Item> {
         // Check if we can advance to the desired offset
         match self.current.checked_add(n) {
@@ -121,10 +122,12 @@ impl<T: ArrayAccessor> Iterator for ArrayIter<T> {
         self.next()
     }
 
+    #[inline]
     fn last(mut self) -> Option<Self::Item> {
         self.next_back()
     }
 
+    #[inline]
     fn count(self) -> usize
     where
         Self: Sized,
@@ -152,6 +155,7 @@ impl<T: ArrayAccessor> DoubleEndedIterator for ArrayIter<T> {
         }
     }
 
+    #[inline]
     fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
         // Check if we advance to the one before the desired offset
         match self.current_end.checked_sub(n) {