ClickHouse · Algunenano · May 15, 2026 · May 14, 2026 · May 14, 2026
diff --git a/.clang-format b/.clang-format
@@ -31,7 +31,7 @@ IndentCaseLabels: true
 SpaceAfterTemplateKeyword: true
 SpaceBeforeCpp11BracedList: false
 SortIncludes: true
-IndentPPDirectives: None
+IndentPPDirectives: AfterHash
 IncludeCategories:
   - Regex: '^<[a-z_]+>'
     Priority: 1

diff --git a/.claude/skills/perf-report/SKILL.md b/.claude/skills/perf-report/SKILL.md
@@ -44,12 +44,12 @@ Do NOT summarize, collapse, or hide entries. Do NOT dismiss anything as "noise"
 
 ### 3. Cross-reference with master history
 
-**This step is MANDATORY.** For every test that shows as slower or faster above 1.10x, check the public CI database to determine if this is a known flaky test or a genuine change introduced by the PR. Do NOT skip this step or use alternative approaches (like manually fetching perf reports from other PRs).
+For every test that shows as slower or faster above 1.10x, check the public CI database to determine if this is a known flaky test or a genuine change introduced by the PR.
 
-Query the `default.checks` table on `play.clickhouse.com` with `user=explorer`:
+Query the public CI database:
 
 ```bash
-clickhouse client --format PrettyCompactNoEscapes --host play.clickhouse.com --user explorer --secure --query "
+clickhouse client --host play.clickhouse.com --user explorer --secure -q "
 SELECT
     replaceRegexpOne(test_name, '::(new|old)$', '') AS test,
     countIf(test_status = 'slower') AS slower_count,
@@ -58,25 +58,22 @@ SELECT
     count() AS total_runs
 FROM default.checks
 WHERE pull_request_number = 0
-  AND check_name LIKE '%Performance%amd%'
+  AND check_name LIKE '%Performance%amd%'  -- or arm
   AND check_start_time >= now() - INTERVAL 30 DAY
   AND test_name IN (
-    'norm_distance #2::new',
-    'array_sort #0::new'
+    'test_name #N::new',
+    ...
   )
 GROUP BY test
 ORDER BY slower_count DESC, test
 "
 ```
 
-Run **one query per architecture** — use `'%Performance%amd%'` for x86 and `'%Performance%arm%'` for ARM.
-
-**Critical details:**
-- **Host:** `play.clickhouse.com`, **user:** `explorer` (NOT `play`)
-- **Table:** `default.checks` (NOT `perftest` or other tables)
-- `pull_request_number = 0` filters to master-only commits (no PR noise)
-- Test names in the DB have `::new` and `::old` suffixes — always query with `::new`
-- Include ALL changed tests in a single IN clause to minimize round-trips
+**Important:**
+- `pull_request_number = 0` means master commits
+- Test names in the DB have `::new` and `::old` suffixes — query with `::new`
+- Use `%amd%` for AMD results and `%arm%` for ARM results
+- Query both architectures separately
 
 ### 4. Classify each change
 

diff --git a/cmake/cpu_features.cmake b/cmake/cpu_features.cmake
@@ -85,42 +85,27 @@ elseif (ARCH_PPC64LE)
 
 elseif (ARCH_AMD64)
     # x86-64 microarchitecture levels (https://en.wikipedia.org/wiki/X86-64#Microarchitecture_levels):
-    #   1 - SSE2 baseline, maximum compatibility with older/embedded hardware
-    #   2 - SSE4.2, SSSE3, POPCNT (ClickHouse's historical baseline)
-    #   3 - AVX2, BMI1/2, FMA, F16C, LZCNT, MOVBE etc. (default)
-    #   4 - AVX-512F/BW/CD/DQ/VL
-    set (X86_ARCH_LEVEL "3" CACHE STRING "x86-64 microarchitecture level (1, 2, 3, 4)")
+    #   1 — SSE2 baseline, maximum compatibility with older/embedded hardware
+    #   2 — SSE4.2, SSSE3, POPCNT (default, matches ClickHouse's historical baseline)
+    #   3 — AVX2, BMI1/2, FMA, F16C etc.
+    #   4 — AVX-512F/BW/CD/DQ/VL
+    set (X86_ARCH_LEVEL "2" CACHE STRING "x86-64 microarchitecture level (1, 2, 3, 4)")
     set_property (CACHE X86_ARCH_LEVEL PROPERTY STRINGS "1" "2" "3" "4")
 
     if (NOT X86_ARCH_LEVEL MATCHES "^[1-4]$")
         message (FATAL_ERROR "X86_ARCH_LEVEL must be one of: 1, 2, 3, 4 (got '${X86_ARCH_LEVEL}')")
     endif ()
 
-    # Best-effort check: verify that the build host supports the requested microarchitecture level. Build-time tools
-    # (tablegen, code generators) are compiled with these flags and will crash with SIGILL otherwise.
+    # Same best-effort check for x86 as above for ARM.
     if (OS_LINUX AND CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "amd64|x86_64" AND X86_ARCH_LEVEL VERSION_GREATER_EQUAL 2)
-        # Test for a representative flag at each level. We intentionally keep this simple - no real CPU has avx2 without
-        # fma/bmi2, so checking the headline flag is enough while avoiding false positives from /proc/cpuinfo quirks
-        # (containers, nested virtualization, unusual flag naming).
-        set (X86_REPRESENTATIVE_FLAG "sse4_2")
-        if (X86_ARCH_LEVEL VERSION_GREATER_EQUAL 3)
-            set (X86_REPRESENTATIVE_FLAG "avx2")
-        endif ()
-        if (X86_ARCH_LEVEL VERSION_GREATER_EQUAL 4)
-            # `x86-64-v4` requires AVX-512 F/BW/CD/DQ/VL. Knights Landing has `avx512f` but lacks BW/DQ/VL, so check one
-            # of those instead - any CPU with `avx512vl` will also have F.
-            set (X86_REPRESENTATIVE_FLAG "avx512vl")
-        endif ()
+        # Test for flags in the default v2 profile.
         execute_process(
-            COMMAND grep -P "(?=.*${X86_REPRESENTATIVE_FLAG})" /proc/cpuinfo
+            COMMAND grep -P "^(?=.*ssse3)(?=.*sse4_1)(?=.*sse4_2)" /proc/cpuinfo
             OUTPUT_VARIABLE FLAGS)
         if (NOT FLAGS)
-            message (FATAL_ERROR
-                "The build machine does not support x86-64-v${X86_ARCH_LEVEL} "
-                "(${X86_REPRESENTATIVE_FLAG} not found in /proc/cpuinfo). "
-                "Run cmake with -DX86_ARCH_LEVEL=<level> to lower the requirement.")
-        endif ()
-    endif ()
+            MESSAGE(FATAL_ERROR "The build machine does not satisfy the minimum CPU requirements, try to run cmake with -DX86_ARCH_LEVEL=1")
+        endif()
+    endif()
 
     # ClickHouse can be cross-compiled (e.g. on an ARM host for x86) but it is also possible to build ClickHouse on x86 w/o AVX for x86 w/
     # AVX. We only assume that the compiler can emit certain SIMD instructions, we don't care if the host system is able to run the binary.
@@ -134,6 +119,7 @@ elseif (ARCH_AMD64)
         set (COMPILER_FLAGS "${COMPILER_FLAGS} -mpclmul")
         list (APPEND RUSTFLAGS_CPU "-C" "target-feature=+pclmulqdq")
     endif ()
+
 else ()
     # RISC-V + exotic platforms
 endif ()
diff --git a/cmake/linux/default_libs.cmake b/cmake/linux/default_libs.cmake
@@ -13,8 +13,21 @@ endif()
 
 if (ENABLE_LLVM_LIBC_MATH)
     link_directories("${CMAKE_BINARY_DIR}/contrib/libllvmlibc-cmake")
-    target_link_libraries(global-libs INTERFACE libllvmlibc)
-    set (DEFAULT_LIBS "${DEFAULT_LIBS} -llibllvmlibc")
+
+    if (ARCH_AMD64)
+        if (X86_ARCH_LEVEL VERSION_LESS 2)
+            # Compat mode: single library, no dispatch
+            target_link_libraries(global-libs INTERFACE libllvmlibc)
+            set (DEFAULT_LIBS "${DEFAULT_LIBS} -llibllvmlibc")
+        else()
+            # Dispatch mode: v2/v3 variants with runtime CPU detection
+            target_link_libraries(global-libs INTERFACE llvmlibc_dispatch libllvmlibc_x86_64_v2 libllvmlibc_x86_64_v3)
+            set (DEFAULT_LIBS "${DEFAULT_LIBS} -lllvmlibc_dispatch -llibllvmlibc_x86_64_v2 -llibllvmlibc_x86_64_v3")
+        endif()
+    elseif (ARCH_AARCH64)
+        target_link_libraries(global-libs INTERFACE libllvmlibc)
+        set (DEFAULT_LIBS "${DEFAULT_LIBS} -llibllvmlibc")
+    endif()
 endif()
 
 if (OS_ANDROID)

diff --git a/cmake/localize_rust_c_symbols.sh b/cmake/localize_rust_c_symbols.sh
diff --git a/contrib/corrosion-cmake/CMakeLists.txt b/contrib/corrosion-cmake/CMakeLists.txt
@@ -227,7 +227,6 @@ function(clickhouse_import_crate)
     enable_dummy_launchers_if_needed()
 endfunction()
 
-# Configure a Rust crate target with ClickHouse-specific flags.
 function(clickhouse_config_crate_flags target_name)
     corrosion_set_env_vars(${target_name} "CFLAGS=${RUST_CFLAGS}")
     corrosion_set_env_vars(${target_name} "CXXFLAGS=${RUST_CXXFLAGS}")
@@ -258,46 +257,4 @@ function(clickhouse_config_crate_flags target_name)
     # Refs: https://github.com/rust-lang/cargo/issues/15099#issuecomment-2732847355
     corrosion_set_env_vars(${target_name} "CARGO_NET_OFFLINE=true")
     corrosion_link_libraries(${target_name} cxx)
-
-    # Localize all C-namespace symbols from Rust static libraries so they
-    # don't shadow our own implementations (libllvmlibc, glibc-compat).
-    # Rust's compiler_builtins exports cbrt, fma, sin, etc. as global symbols;
-    # without this, they silently win at link time and bypass our -falign-functions=64
-    # and -march flags, causing performance regressions.
-    #
-    # For workspace crates the .a may land in a parent directory rather than
-    # CMAKE_CURRENT_BINARY_DIR.  Set IMPORTED_LOCATION on the target before
-    # calling this function if the default path is wrong (see wasmtime for an
-    # example).
-    get_target_property(_rust_lib_path ${target_name} IMPORTED_LOCATION)
-    if (NOT _rust_lib_path OR _rust_lib_path MATCHES "NOTFOUND")
-        set(_rust_lib_path "${CMAKE_CURRENT_BINARY_DIR}/lib${target_name}.a")
-    endif()
-
-    # Skip on Darwin (Mach-O), ppc64le (broken .eh_frame), and dummy builds.
-    if (CMAKE_OBJCOPY AND NOT OS_DARWIN
-        AND NOT CMAKE_SYSTEM_PROCESSOR STREQUAL "ppc64le"
-        AND NOT CMAKE_AR MATCHES "dummy_compiler_linker")
-        # Verify the library path looks plausible at configure time.  The file
-        # won't exist yet (cargo hasn't run), but the parent directory must exist
-        # and the filename must end in .a — otherwise someone forgot to set
-        # IMPORTED_LOCATION for a workspace subcrate.
-        get_filename_component(_rust_lib_dir "${_rust_lib_path}" DIRECTORY)
-        if (NOT IS_DIRECTORY "${_rust_lib_dir}")
-            message(FATAL_ERROR
-                "localize_rust_c_symbols: output directory '${_rust_lib_dir}' for "
-                "target '${target_name}' does not exist.  If this is a workspace "
-                "subcrate, set IMPORTED_LOCATION on the target before calling "
-                "clickhouse_config_crate_flags().  Expected library: ${_rust_lib_path}")
-        endif()
-
-        add_custom_target(localize_rust_c_${target_name}
-            COMMAND bash "${ClickHouse_SOURCE_DIR}/cmake/localize_rust_c_symbols.sh"
-                "${_rust_lib_path}" "${CMAKE_AR}" "${CMAKE_OBJCOPY}" "${NM_PATH}"
-            COMMENT "Localizing C-namespace symbols in ${target_name}"
-            VERBATIM
-        )
-        add_dependencies(localize_rust_c_${target_name} cargo-build_${target_name})
-        add_dependencies(${target_name} localize_rust_c_${target_name})
-    endif()
 endfunction()
diff --git a/contrib/fastops-cmake/CMakeLists.txt b/contrib/fastops-cmake/CMakeLists.txt
@@ -11,33 +11,27 @@ endif()
 
 set(LIBRARY_DIR "${ClickHouse_SOURCE_DIR}/contrib/fastops")
 
-set(SRCS
-    "${LIBRARY_DIR}/fastops/fastops.cpp"
-)
+set(SRCS "")
 
-if (ARCH_AMD64)
-    list(APPEND SRCS "${LIBRARY_DIR}/fastops/avx2/ops_avx2.cpp")
-endif()
-
-if (ARCH_AMD64 AND X86_ARCH_LEVEL VERSION_LESS 3)
-    # Below v3: need runtime dispatch with AVX-only and Plain fallbacks.
-    list(APPEND SRCS
-        "${LIBRARY_DIR}/fastops/avx/ops_avx.cpp"
-        "${LIBRARY_DIR}/fastops/plain/ops_plain.cpp"
-        "${LIBRARY_DIR}/fastops/core/avx_id.cpp"
-    )
+if(ARCH_AMD64)
+    set (SRCS ${SRCS} "${LIBRARY_DIR}/fastops/avx/ops_avx.cpp")
     set_source_files_properties("${LIBRARY_DIR}/fastops/avx/ops_avx.cpp" PROPERTIES COMPILE_FLAGS "-mavx -DNO_AVX2")
-    set_source_files_properties("${LIBRARY_DIR}/fastops/avx2/ops_avx2.cpp" PROPERTIES COMPILE_FLAGS "-mavx2 -mfma -DNO_AVX")
+
+    set (SRCS ${SRCS} "${LIBRARY_DIR}/fastops/avx2/ops_avx2.cpp")
+    set_source_files_properties("${LIBRARY_DIR}/fastops/avx2/ops_avx2.cpp" PROPERTIES COMPILE_FLAGS "-mavx2 -mfma")
+
+    set (SRCS ${SRCS} "${LIBRARY_DIR}/fastops/plain/ops_plain.cpp" "${LIBRARY_DIR}/fastops/core/avx_id.cpp")
 elseif(ARCH_AARCH64)
-    list(APPEND SRCS "${LIBRARY_DIR}/fastops/neon/ops_neon.cpp")
+    set (SRCS ${SRCS} "${LIBRARY_DIR}/fastops/neon/ops_neon.cpp")
 
     # SVE requires arm_sve.h which is only available on Linux toolchains (not Darwin/FreeBSD).
     if(OS_LINUX)
-        list(APPEND SRCS "${LIBRARY_DIR}/fastops/sve/ops_sve.cpp")
+        set (SRCS ${SRCS} "${LIBRARY_DIR}/fastops/sve/ops_sve.cpp")
         set_source_files_properties("${LIBRARY_DIR}/fastops/sve/ops_sve.cpp" PROPERTIES COMPILE_FLAGS "-march=armv8-a+sve")
     endif()
 endif()
 
+set (SRCS ${SRCS} "${LIBRARY_DIR}/fastops/fastops.cpp")
 
 add_library(_fastops ${SRCS})
 

diff --git a/contrib/libdivide-cmake/libdivide-config.h b/contrib/libdivide-cmake/libdivide-config.h
@@ -1,9 +1,9 @@
-#if defined(__AVX512F__) || defined(__AVX512BW__) || defined(__AVX512VL__)
+#if defined(__SSE2__)
+#    define LIBDIVIDE_SSE2
+#elif defined(__AVX512F__) || defined(__AVX512BW__) || defined(__AVX512VL__)
 #    define LIBDIVIDE_AVX512
 #elif defined(__AVX2__)
 #    define LIBDIVIDE_AVX2
-#elif defined(__SSE2__)
-#    define LIBDIVIDE_SSE2
 #elif defined(__aarch64__) && defined(__ARM_NEON)
 #    define LIBDIVIDE_NEON
 #endif