From 077168a525b14abe03a049535f7b7aff02e666d7 Mon Sep 17 00:00:00 2001
From: Benjamin Kietzman <bengilgit@gmail.com>
Date: Thu, 15 Jun 2023 17:04:48 -0400
Subject: [PATCH] Update cpp/src/arrow/array/data.cc

---
 cpp/src/arrow/array/data.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cpp/src/arrow/array/data.cc b/cpp/src/arrow/array/data.cc
index 34a336303d894..7b1b9e6c9f62d 100644
--- a/cpp/src/arrow/array/data.cc
+++ b/cpp/src/arrow/array/data.cc
@@ -384,7 +384,7 @@ void ArraySpan::FillFromScalar(const Scalar& value) {
     // Dense union needs scratch space to store both offsets and a type code
     struct UnionScratchSpace {
       uint8_t type_code;
-      alignas(int32_t) uint8_t offsets[sizeof(int32_t) * 2];
+      alignas(int64_t) uint8_t offsets[sizeof(int32_t) * 2];
     };
     auto* union_scratch_space = new (scratch_space) UnionScratchSpace{};