diff --git a/src/timely-util/src/containers.rs b/src/timely-util/src/containers.rs
index e7d61b827f2c3..7bcf8b04a96fd 100644
--- a/src/timely-util/src/containers.rs
+++ b/src/timely-util/src/containers.rs
@@ -63,7 +63,7 @@ mod alloc {
 mod container {
     use columnar::Columnar;
     use columnar::Container as _;
-    use columnar::bytes::{EncodeDecode, Sequence};
+    use columnar::bytes::{EncodeDecode, Indexed};
     use columnar::common::IterOwn;
     use columnar::{Clear, FromBytes, Index, Len};
     use mz_ore::region::Region;
@@ -97,12 +97,12 @@ mod container {
                 Column::Typed(t) => t.borrow(),
                 Column::Bytes(b) => {
                     <<C::Container as columnar::Container>::Borrowed<'_>>::from_bytes(
-                        &mut Sequence::decode(bytemuck::cast_slice(b)),
+                        &mut Indexed::decode(bytemuck::cast_slice(b)),
                     )
                 }
                 Column::Align(a) => {
                     <<C::Container as columnar::Container>::Borrowed<'_>>::from_bytes(
-                        &mut Sequence::decode(a),
+                        &mut Indexed::decode(a),
                     )
                 }
             }
@@ -214,7 +214,7 @@ mod container {
         #[inline]
         fn length_in_bytes(&self) -> usize {
             match self {
-                Column::Typed(t) => Sequence::length_in_bytes(&t.borrow()),
+                Column::Typed(t) => Indexed::length_in_bytes(&t.borrow()),
                 Column::Bytes(b) => b.len(),
                 Column::Align(a) => 8 * a.len(),
             }
@@ -223,7 +223,7 @@ mod container {
         #[inline]
         fn into_bytes<W: ::std::io::Write>(&self, writer: &mut W) {
             match self {
-                Column::Typed(t) => Sequence::write(writer, &t.borrow()).unwrap(),
+                Column::Typed(t) => Indexed::write(writer, &t.borrow()).unwrap(),
                 Column::Bytes(b) => writer.write_all(b).unwrap(),
                 Column::Align(a) => writer.write_all(bytemuck::cast_slice(a)).unwrap(),
             }
@@ -234,7 +234,7 @@ mod container {
 mod builder {
     use std::collections::VecDeque;
 
-    use columnar::bytes::{EncodeDecode, Sequence};
+    use columnar::bytes::{EncodeDecode, Indexed};
     use columnar::{Clear, Columnar, Len, Push};
     use timely::container::PushInto;
     use timely::container::{ContainerBuilder, LengthPreservingContainerBuilder};
@@ -263,7 +263,7 @@ mod builder {
             self.current.push(item);
             // If there is less than 10% slop with 2MB backing allocations, mint a container.
             use columnar::Container;
-            let words = Sequence::length_in_words(&self.current.borrow());
+            let words = Indexed::length_in_words(&self.current.borrow());
             let round = (words + ((1 << 18) - 1)) & !((1 << 18) - 1);
             if round - words < round / 10 {
                 /// Move the contents from `current` to an aligned allocation, and push it to `pending`.
@@ -278,7 +278,7 @@ mod builder {
                 {
                     let mut alloc = super::alloc_aligned_zeroed(round);
                     let writer = std::io::Cursor::new(bytemuck::cast_slice_mut(&mut alloc[..]));
-                    Sequence::write(writer, &current.borrow()).unwrap();
+                    Indexed::write(writer, &current.borrow()).unwrap();
                     pending.push_back(Column::Align(alloc));
                     current.clear();
                 }
@@ -491,6 +491,7 @@ mod tests {
     use mz_ore::region::Region;
     use timely::Container;
     use timely::bytes::arc::BytesMut;
+    use timely::container::PushInto;
     use timely::dataflow::channels::ContainerBytes;
 
     use super::*;
@@ -498,7 +499,8 @@ mod tests {
     /// Produce some bytes that are in columnar format.
     fn raw_columnar_bytes() -> Vec<u8> {
         let mut raw = Vec::new();
-        raw.extend(12_u64.to_le_bytes()); // length
+        raw.extend(16_u64.to_le_bytes()); // offsets
+        raw.extend(28_u64.to_le_bytes()); // length
         raw.extend(1_i32.to_le_bytes());
         raw.extend(2_i32.to_le_bytes());
         raw.extend(3_i32.to_le_bytes());
@@ -530,6 +532,19 @@ mod tests {
         assert_eq!(column_align2.iter().collect::<Vec<_>>(), vec![&1, &2, &3]);
     }
 
+    /// Assert the desired contents of raw_columnar_bytes so that diagnosing test failures is
+    /// easier.
+    #[mz_ore::test]
+    fn test_column_known_bytes() {
+        let mut column: Column<i32> = Default::default();
+        column.push_into(1);
+        column.push_into(2);
+        column.push_into(3);
+        let mut data = Vec::new();
+        column.into_bytes(&mut std::io::Cursor::new(&mut data));
+        assert_eq!(data, raw_columnar_bytes());
+    }
+
     #[mz_ore::test]
     fn test_column_from_bytes() {
         let raw = raw_columnar_bytes();