From 6c1444c45f30b7a1a13ca3e9aaa60e1a696a2c4b Mon Sep 17 00:00:00 2001
From: Mikhail Kot <mikhail@spiraldb.com>
Date: Wed, 3 Jun 2026 12:09:31 +0100
Subject: [PATCH] initial

Signed-off-by: Mikhail Kot <mikhail@spiraldb.com>
---
 vortex-layout/src/layouts/chunked/mod.rs    | 12 +++++-------
 vortex-layout/src/layouts/chunked/reader.rs | 19 ++++++-------------
 2 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/vortex-layout/src/layouts/chunked/mod.rs b/vortex-layout/src/layouts/chunked/mod.rs
index 82fcb650607..59f41394168 100644
--- a/vortex-layout/src/layouts/chunked/mod.rs
+++ b/vortex-layout/src/layouts/chunked/mod.rs
@@ -103,10 +103,9 @@ impl VTable for Chunked {
         let new_children = OwnedLayoutChildren::layout_children(children);
 
         // Recalculate chunk offsets based on new children
-        let mut chunk_offsets = Vec::with_capacity(new_children.nchildren() + 1);
-        chunk_offsets.push(0);
+        let mut chunk_offsets = vec![0; new_children.nchildren() + 1];
         for i in 0..new_children.nchildren() {
-            chunk_offsets.push(chunk_offsets[i] + new_children.child_row_count(i));
+            chunk_offsets[i + 1] = chunk_offsets[i] + new_children.child_row_count(i);
         }
 
         layout.children = new_children;
@@ -132,12 +131,11 @@ pub struct ChunkedLayout {
 
 impl ChunkedLayout {
     pub fn new(row_count: u64, dtype: DType, children: Arc<dyn LayoutChildren>) -> Self {
-        let mut chunk_offsets = Vec::with_capacity(children.nchildren() + 1);
-
-        chunk_offsets.push(0);
+        let mut chunk_offsets = vec![0; children.nchildren() + 1];
         for i in 0..children.nchildren() {
-            chunk_offsets.push(chunk_offsets[i] + children.child_row_count(i));
+            chunk_offsets[i + 1] = chunk_offsets[i] + children.child_row_count(i);
         }
+
         assert_eq!(
             chunk_offsets[children.nchildren()],
             row_count,
diff --git a/vortex-layout/src/layouts/chunked/reader.rs b/vortex-layout/src/layouts/chunked/reader.rs
index 39bd8b27b7c..769441e3bc2 100644
--- a/vortex-layout/src/layouts/chunked/reader.rs
+++ b/vortex-layout/src/layouts/chunked/reader.rs
@@ -39,8 +39,6 @@ pub struct ChunkedReader {
     layout: ChunkedLayout,
     name: Arc<str>,
     lazy_children: LazyReaderChildren,
-    /// Row offset for each chunk
-    chunk_offsets: Vec<u64>,
 }
 
 static UNKNOWN: LazyLock<Arc<str>> = LazyLock::new(|| Arc::from("chunked-child"));
@@ -53,13 +51,6 @@ impl ChunkedReader {
         session: &VortexSession,
     ) -> Self {
         let nchildren = layout.nchildren();
-
-        let mut chunk_offsets = vec![0; nchildren + 1];
-        for i in 1..nchildren {
-            chunk_offsets[i] = chunk_offsets[i - 1] + layout.children.child_row_count(i - 1);
-        }
-        chunk_offsets[nchildren] = layout.row_count();
-
         let dtypes = vec![layout.dtype.clone(); nchildren];
 
         // format!() has non-marginal overhead for short queries like random
@@ -84,7 +75,6 @@ impl ChunkedReader {
             layout,
             name,
             lazy_children,
-            chunk_offsets,
         }
     }
 
@@ -94,22 +84,25 @@ impl ChunkedReader {
     }
 
     fn chunk_offset(&self, idx: usize) -> u64 {
-        self.chunk_offsets.get(idx).copied().unwrap_or_else(|| {
+        if idx >= self.layout.chunk_offsets.len() {
             vortex_panic!(
                 "Internal error: Chunk offset {idx} out of bounds (num_children: {}, num_offsets: {}). \
                 This indicates a bug in ChunkedReader initialization or chunk_range calculation.",
                 self.layout.nchildren(),
-                self.chunk_offsets.len()
+                self.layout.chunk_offsets.len()
             )
-        })
+        }
+        self.layout.chunk_offsets[idx]
     }
 
     fn chunk_range(&self, row_range: &Range<u64>) -> Range<usize> {
         let start_chunk = self
+            .layout
             .chunk_offsets
             .binary_search(&row_range.start)
             .unwrap_or_else(|x| x.saturating_sub(1));
         let end_chunk = self
+            .layout
             .chunk_offsets
             .binary_search(&row_range.end)
             .unwrap_or_else(|x| x);