diff --git a/Cargo.toml b/Cargo.toml
index 35179561e14..c0862456e0b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -367,7 +367,8 @@ use_debug = "deny"
 
 [profile.release]
 codegen-units = 1
-# Turn LTO off, as it breaks when vortex-duckdb-ext is linked.
+# Our general performance should not be dependent on LTO since crates that use
+# Vortex may choose not to have LTO.
 lto = "off"
 
 [profile.release_debug]
diff --git a/vortex-duckdb/build.rs b/vortex-duckdb/build.rs
index 340651027a1..c3ab196a8ce 100644
--- a/vortex-duckdb/build.rs
+++ b/vortex-duckdb/build.rs
@@ -328,10 +328,14 @@ fn c2rust(crate_dir: &Path, duckdb_include_dir: &Path) {
     }
 }
 
-fn cpp(duckdb_include_dir: &Path) {
+fn cpp(duckdb_include_dir: &Path, build_type: &str) {
+    let mut flags = vec!["-Wall", "-Wextra", "-Wpedantic", "-Werror"];
+    if build_type == "release" {
+        flags.extend_from_slice(&["-flto=auto"]);
+    }
     cc::Build::new()
         .std("c++20")
-        .flags(["-Wall", "-Wextra", "-Wpedantic"])
+        .flags(flags)
         .cpp(true)
         .include(duckdb_include_dir)
         .include("cpp/include")
@@ -392,8 +396,12 @@ fn main() {
 
     let crate_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
     let duckdb_dir = crate_dir.join("duckdb");
-    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-    let library_dir = out_dir.join(format!("duckdb-lib-{version}"));
+    // Cargo has changed OUT_DIR behaviour so for every branch and build we have
+    // a different directory e.g.
+    // ~/vortex/target/release/build/vortex-duckdb-b6bc1fb73230910e/out/duckdb-lib-v1.5.2
+    // We don't want this since artifacts are the same.
+    // We can't use CARGO_TARGET_DIR since it's out of tree.
+    let library_dir = duckdb_dir.join(format!("duckdb-lib-{version}"));
 
     let library_dir_str = library_dir.display();
     println!("cargo:rustc-link-search=native={library_dir_str}");
@@ -414,7 +422,7 @@ fn main() {
     // Alternatively, set LD_LIBRARY_PATH (Linux) or DYLD_LIBRARY_PATH (macOS) at runtime.
     println!("cargo:lib_dir={library_dir_str}");
 
-    let source_dir = out_dir.join(format!("duckdb-source-{version}"));
+    let source_dir = duckdb_dir.join(format!("duckdb-source-{version}"));
     let source_archive_url = match &version {
         DuckDBVersion::Release(v) => format!("{DUCKDB_SOURCE_RELEASE_URL}/v{v}.zip"),
         DuckDBVersion::Commit(c) => format!("{DUCKDB_SOURCE_COMMIT_URL}/{c}.zip"),
@@ -429,10 +437,6 @@ fn main() {
         extract(&source_archive_path, &source_dir);
     }
 
-    drop(fs::remove_file(&duckdb_dir));
-    drop(fs::remove_dir_all(&duckdb_dir));
-    std::os::unix::fs::symlink(&source_dir, &duckdb_dir).unwrap();
-
     let has_debug_env =
         env::var("VX_DUCKDB_DEBUG").is_ok_and(|v| matches!(v.as_str(), "1" | "true"));
     let build_type = match has_debug_env {
@@ -449,6 +453,6 @@ fn main() {
 
     let duckdb_include_dir = inner_dir.join("src").join("include");
     c2rust(&crate_dir, &duckdb_include_dir);
-    cpp(&duckdb_include_dir);
+    cpp(&duckdb_include_dir, build_type);
     rust2c(&crate_dir);
 }
diff --git a/vortex-duckdb/cpp/CMakeLists.txt b/vortex-duckdb/cpp/CMakeLists.txt
index 9671d93dd6d..ae1ffdfb0cd 100644
--- a/vortex-duckdb/cpp/CMakeLists.txt
+++ b/vortex-duckdb/cpp/CMakeLists.txt
@@ -3,9 +3,8 @@
 
 # This CMake project is only used for IDE support (CLion, etc.).
 # See build.rs for the actual build definition.
-#
 # Prerequisites: Run `cargo build -p vortex-duckdb` first to download DuckDB
-# source and create the symlink at ../duckdb.
+# source
 #
 # If your editor relies on a compilation database to enable LSP functionality,
 # you can generate it by running `cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON` or
@@ -23,11 +22,11 @@ if (NOT CMAKE_BUILD_TYPE)
 endif()
 
 # Enable compiler warnings (matching build.rs flags).
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wpedantic")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wpedantic -Werror")
+set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -Wall -Wextra -Wpedantic -Werror -O3")
 
-# Find DuckDB include directory via the symlink created by build.rs.
-# The symlink points to target/duckdb-source-vX.Y.Z which contains duckdb-X.Y.Z/
-file(GLOB DUCKDB_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/../duckdb/duckdb-*")
+# Find DuckDB include directory containing duckdb-source-vX.Y.Z which contains duckdb-X.Y.Z/
+file(GLOB DUCKDB_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/../duckdb/duckdb-source-*/duckdb-*/")
 if(DUCKDB_DIRS)
     list(GET DUCKDB_DIRS 0 DUCKDB_DIR)
     set(DUCKDB_INCLUDE "${DUCKDB_DIR}/src/include")
@@ -35,7 +34,7 @@ if(DUCKDB_DIRS)
 else()
     message(FATAL_ERROR
         "DuckDB source not found at ../duckdb/duckdb-*\n"
-        "Run 'cargo build -p vortex-duckdb' first to download DuckDB and create the symlink."
+        "Run 'cargo build -p vortex-duckdb' first to download DuckDB"
     )
 endif()