diff --git a/codecz/src/utils.rs b/codecz/src/utils.rs
index 771b2d6c4a..30a4a0e87f 100644
--- a/codecz/src/utils.rs
+++ b/codecz/src/utils.rs
@@ -14,22 +14,24 @@
 
 extern crate alloc;
 
-use crate::{AlignedVec, ALIGNED_ALLOCATOR};
 use alloc::sync::Arc;
-use arrow_buffer::{BooleanBuffer, Buffer};
 use core::ptr::NonNull;
 
-pub fn into_u32_vec(bb: &BooleanBuffer, cardinality: usize) -> AlignedVec<u32> {
-    let mut vec: AlignedVec<u32> = AlignedVec::with_capacity_in(cardinality, ALIGNED_ALLOCATOR);
+use arrow_buffer::{BooleanBuffer, Buffer};
+
+use crate::{AlignedVec, ALIGNED_ALLOCATOR};
+
+pub fn into_u64_vec(bb: &BooleanBuffer, cardinality: usize) -> AlignedVec<u64> {
+    let mut vec: AlignedVec<u64> = AlignedVec::with_capacity_in(cardinality, ALIGNED_ALLOCATOR);
     if cardinality > 0 {
         for idx in bb.set_indices() {
-            vec.push(idx as u32);
+            vec.push(idx as u64);
         }
     }
     vec
 }
 
-pub fn gather_patches<T: Copy + Sized>(data: &[T], indices: &[u32]) -> AlignedVec<T> {
+pub fn gather_patches<T: Copy + Sized>(data: &[T], indices: &[u64]) -> AlignedVec<T> {
     let mut vec: AlignedVec<T> = AlignedVec::with_capacity_in(indices.len(), ALIGNED_ALLOCATOR);
     for idx in indices {
         vec.push(data[*idx as usize]);
diff --git a/vortex-alp/src/compress.rs b/vortex-alp/src/compress.rs
index d44a5a55d2..da428c719f 100644
--- a/vortex-alp/src/compress.rs
+++ b/vortex-alp/src/compress.rs
@@ -129,7 +129,7 @@ where
     let patches = if num_exceptions == 0 {
         None
     } else {
-        let patch_indices = codecz::utils::into_u32_vec(&exceptions_idx, num_exceptions);
+        let patch_indices = codecz::utils::into_u64_vec(&exceptions_idx, num_exceptions);
         let patch_values = codecz::utils::gather_patches(
             values.buffer().typed_data::<T>(),
             patch_indices.as_slice(),
diff --git a/vortex-ffor/src/compress.rs b/vortex-ffor/src/compress.rs
index 3e1ed8d0c1..1ec08b2aed 100644
--- a/vortex-ffor/src/compress.rs
+++ b/vortex-ffor/src/compress.rs
@@ -14,7 +14,6 @@
 
 use log::debug;
 
-use crate::downcast::DowncastFFOR;
 use codecz::ffor;
 use codecz::ffor::{FforEncoded, SupportsFFoR};
 use vortex::array::downcast::DowncastArrayBuiltin;
@@ -27,6 +26,7 @@ use vortex::ptype::NativePType;
 use vortex::scalar::{ListScalarVec, NullableScalar, Scalar};
 use vortex::stats::Stat;
 
+use crate::downcast::DowncastFFOR;
 use crate::ffor::{FFORArray, FFoREncoding};
 
 impl EncodingCompression for FFoREncoding {
@@ -145,7 +145,7 @@ where
     } else {
         let (patch_values, patch_indices) =
             ffor::collect_exceptions(values, num_bits, min_val, num_exceptions).unwrap();
-        let patch_indices = codecz::utils::into_u32_vec(&patch_indices, num_exceptions);
+        let patch_indices = codecz::utils::into_u64_vec(&patch_indices, num_exceptions);
         Some(
             SparseArray::new(
                 PrimitiveArray::from_vec_in(patch_indices).boxed(),