implement benchmark

Timer precision: 41 ns
listview_rebuild  fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ rebuild_naive  109.5 µs      │ 192.2 µs      │ 121.1 µs      │ 122 µs        │ 100     │ 100

Signed-off-by: Andrew Duffy <[email protected]>

Author: a10y

Cargo.lock

@@ -30,5 +30,11 @@ vortex-vector = { workspace = true }
 zstd = { workspace = true }
 
 [dev-dependencies]
+divan = { workspace = true }
 rstest = { workspace = true }
 vortex-array = { workspace = true, features = ["test-harness"] }
+
+[[bench]]
+name = "listview_rebuild"
+path = "benches/listiew_rebuild.rs"
+harness = false

encodings/zstd/Cargo.toml

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright the Vortex contributors
+
+use divan::Bencher;
+use vortex_array::IntoArray;
+use vortex_array::arrays::{ListViewArray, ListViewRebuildMode, VarBinViewArray};
+use vortex_array::validity::Validity;
+use vortex_buffer::Buffer;
+use vortex_zstd::ZstdArray;
+
+#[divan::bench]
+fn rebuild_naive(bencher: Bencher) {
+    let dudes = VarBinViewArray::from_iter_str(["Washington", "Adams", "Jefferson", "Madison"])
+        .into_array();
+    let dudes = ZstdArray::from_array(dudes, 9, 1024).unwrap().into_array();
+
+    let offsets = std::iter::repeat_n(0u32, 1024)
+        .collect::<Buffer<u32>>()
+        .into_array();
+    let sizes = [0u64, 1, 2, 3, 4]
+        .into_iter()
+        .cycle()
+        .take(1024)
+        .collect::<Buffer<u64>>()
+        .into_array();
+
+    let list_view = ListViewArray::new(dudes, offsets, sizes, Validity::NonNullable);
+
+    bencher.bench_local(|| list_view.rebuild(ListViewRebuildMode::MakeZeroCopyToList))
+}
+
+fn main() {
+    divan::main()
+}

encodings/zstd/benches/listiew_rebuild.rs

@@ -8,7 +8,6 @@ use vortex_error::VortexExpect;
 use vortex_scalar::Scalar;
 
 use crate::arrays::{ChunkedArray, ListViewArray};
-use crate::builders::ArrayBuilder;
 use crate::vtable::ValidityHelper;
 use crate::{Array, IntoArray, ToCanonical, compute};
 
@@ -92,7 +91,7 @@ impl ListViewArray {
         // slicing with them.
         let elements_canonical = self.elements().to_canonical().into_array();
         let offsets_canonical = self.offsets().to_primitive();
-        let sizes_canonical = self.offsets().to_primitive();
+        let sizes_canonical = self.sizes().to_primitive();
 
         let offsets_canonical = offsets_canonical.as_slice::<O>();
         let sizes_canonical = sizes_canonical.as_slice::<S>();