diff --git a/.clang-tidy b/.clang-tidy
index b0971418e0e..ecb8ac6dcbf 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -203,3 +203,5 @@ CheckOptions:
     value: CamelCase
   - key: readability-identifier-naming.UsingCase
     value: CamelCase
+  - key: modernize-loop-convert.UseCxx20ReverseRanges
+    value: false
diff --git a/cmake/analysis.cmake b/cmake/analysis.cmake
index 267bb34248b..24d8168e2c0 100644
--- a/cmake/analysis.cmake
+++ b/cmake/analysis.cmake
@@ -6,7 +6,7 @@ if (ENABLE_CLANG_TIDY)
         message(FATAL_ERROR "clang-tidy requires CMake version at least 3.6.")
     endif()
 
-    find_program (CLANG_TIDY_PATH NAMES "clang-tidy" "clang-tidy-11" "clang-tidy-10" "clang-tidy-9" "clang-tidy-8")
+    find_program (CLANG_TIDY_PATH NAMES "clang-tidy" "clang-tidy-12" "clang-tidy-11" "clang-tidy-10" "clang-tidy-9" "clang-tidy-8")
 
     if (CLANG_TIDY_PATH)
         message(STATUS
diff --git a/cmake/freebsd/toolchain-x86_64.cmake b/cmake/freebsd/toolchain-x86_64.cmake
index d9839ec74ee..f9e45686db7 100644
--- a/cmake/freebsd/toolchain-x86_64.cmake
+++ b/cmake/freebsd/toolchain-x86_64.cmake
@@ -10,7 +10,7 @@ set (CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)  # disable linkage check - it
 set (CMAKE_AR "/usr/bin/ar" CACHE FILEPATH "" FORCE)
 set (CMAKE_RANLIB "/usr/bin/ranlib" CACHE FILEPATH "" FORCE)
 
-set (LINKER_NAME "lld" CACHE STRING "" FORCE)
+set (LINKER_NAME "ld.lld" CACHE STRING "" FORCE)
 
 set (CMAKE_EXE_LINKER_FLAGS_INIT "-fuse-ld=lld")
 set (CMAKE_SHARED_LINKER_FLAGS_INIT "-fuse-ld=lld")
diff --git a/cmake/linux/toolchain-aarch64.cmake b/cmake/linux/toolchain-aarch64.cmake
index e3924fdc537..b4dc6e45cbb 100644
--- a/cmake/linux/toolchain-aarch64.cmake
+++ b/cmake/linux/toolchain-aarch64.cmake
@@ -13,7 +13,7 @@ set (CMAKE_C_FLAGS_INIT "${CMAKE_C_FLAGS} --gcc-toolchain=${CMAKE_CURRENT_LIST_D
 set (CMAKE_CXX_FLAGS_INIT "${CMAKE_CXX_FLAGS} --gcc-toolchain=${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64")
 set (CMAKE_ASM_FLAGS_INIT "${CMAKE_ASM_FLAGS} --gcc-toolchain=${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64")
 
-set (LINKER_NAME "lld" CACHE STRING "" FORCE)
+set (LINKER_NAME "ld.lld" CACHE STRING "" FORCE)
 
 set (CMAKE_EXE_LINKER_FLAGS_INIT "-fuse-ld=lld")
 set (CMAKE_SHARED_LINKER_FLAGS_INIT "-fuse-ld=lld")
diff --git a/cmake/tools.cmake b/cmake/tools.cmake
index 8ff94ab867b..f94f4b289a3 100644
--- a/cmake/tools.cmake
+++ b/cmake/tools.cmake
@@ -79,8 +79,9 @@ endif ()
 
 if (LINKER_NAME)
     if (COMPILER_CLANG AND (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 12.0.0 OR CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL 12.0.0))
-        set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --ld-path=${LINKER_NAME}")
-        set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} --ld-path=${LINKER_NAME}")
+        find_program (LLD_PATH NAMES ${LINKER_NAME})
+        set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --ld-path=${LLD_PATH}")
+        set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} --ld-path=${LLD_PATH}")
     else ()
         set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fuse-ld=${LINKER_NAME}")
         set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -fuse-ld=${LINKER_NAME}")
diff --git a/docker/builder/Dockerfile b/docker/builder/Dockerfile
index abe102e9c80..9a1041ee743 100644
--- a/docker/builder/Dockerfile
+++ b/docker/builder/Dockerfile
@@ -1,6 +1,6 @@
 FROM ubuntu:20.04
 
-ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=11
+ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=12
 
 RUN sed -i 's|http://archive|http://ru.archive|g' /etc/apt/sources.list
 
diff --git a/docker/builder/build.sh b/docker/builder/build.sh
index d4cf662e91b..7c7a8893751 100755
--- a/docker/builder/build.sh
+++ b/docker/builder/build.sh
@@ -4,7 +4,7 @@ set -e
 #ccache -s # uncomment to display CCache statistics
 mkdir -p /server/build_docker
 cd /server/build_docker
-cmake -G Ninja /server "-DCMAKE_C_COMPILER=$(command -v clang-11)" "-DCMAKE_CXX_COMPILER=$(command -v clang++-11)"
+cmake -G Ninja /server "-DCMAKE_C_COMPILER=$(command -v clang-12)" "-DCMAKE_CXX_COMPILER=$(command -v clang++-12)"
 
 # Set the number of build jobs to the half of number of virtual CPU cores (rounded up).
 # By default, ninja use all virtual CPU cores, that leads to very high memory consumption without much improvement in build time.
diff --git a/docker/packager/binary/Dockerfile b/docker/packager/binary/Dockerfile
index 0393669df48..f5d496ce97f 100644
--- a/docker/packager/binary/Dockerfile
+++ b/docker/packager/binary/Dockerfile
@@ -1,7 +1,7 @@
 #  docker build -t yandex/clickhouse-binary-builder .
 FROM ubuntu:20.04
 
-ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=11
+ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=12
 
 RUN sed -i 's|http://archive|http://ru.archive|g' /etc/apt/sources.list
 
@@ -39,8 +39,6 @@ RUN apt-get update \
         bash \
         build-essential \
         ccache \
-        clang-11 \
-        clang-tidy-11 \
         cmake \
         curl \
         g++-10 \
@@ -50,9 +48,13 @@ RUN apt-get update \
         gperf \
         libicu-dev \
         libreadline-dev \
-        lld-11 \
-        llvm-11 \
-        llvm-11-dev \
+        clang-12 \
+        clang-tidy-12 \
+        lld-12 \
+        llvm-12 \
+        llvm-12-dev \
+        libicu-dev \
+        libreadline-dev \
         moreutils \
         ninja-build \
         pigz \
diff --git a/docker/packager/binary/build.sh b/docker/packager/binary/build.sh
index b9900e34bf1..71402a2fd66 100755
--- a/docker/packager/binary/build.sh
+++ b/docker/packager/binary/build.sh
@@ -4,7 +4,6 @@ set -x -e
 
 mkdir -p build/cmake/toolchain/darwin-x86_64
 tar xJf MacOSX11.0.sdk.tar.xz -C build/cmake/toolchain/darwin-x86_64 --strip-components=1
-
 ln -sf darwin-x86_64 build/cmake/toolchain/darwin-aarch64
 
 mkdir -p build/cmake/toolchain/linux-aarch64
@@ -23,6 +22,7 @@ cd build/build_docker
 rm -f CMakeCache.txt
 # Read cmake arguments into array (possibly empty)
 read -ra CMAKE_FLAGS <<< "${CMAKE_FLAGS:-}"
+env
 cmake --debug-trycompile --verbose=1 -DCMAKE_VERBOSE_MAKEFILE=1 -LA "-DCMAKE_BUILD_TYPE=$BUILD_TYPE" "-DSANITIZE=$SANITIZER" -DENABLE_CHECK_HEAVY_BUILDS=1 "${CMAKE_FLAGS[@]}" ..
 
 ccache --show-config ||:
diff --git a/docker/packager/deb/Dockerfile b/docker/packager/deb/Dockerfile
index 294c8645455..22bba94f250 100644
--- a/docker/packager/deb/Dockerfile
+++ b/docker/packager/deb/Dockerfile
@@ -1,7 +1,7 @@
 # docker build -t yandex/clickhouse-deb-builder .
 FROM ubuntu:20.04
 
-ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=11
+ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=12
 
 RUN sed -i 's|http://archive|http://ru.archive|g' /etc/apt/sources.list
 
@@ -37,17 +37,17 @@ RUN curl -O https://clickhouse-datasets.s3.yandex.net/utils/1/dpkg-deb \
 RUN apt-get update \
     && apt-get install \
         alien \
-        clang-11 \
-        clang-tidy-11 \
+        clang-12 \
+        clang-tidy-12 \
         cmake \
         debhelper \
         devscripts \
         gdb  \
         git \
         gperf \
-        lld-11 \
-        llvm-11 \
-        llvm-11-dev \
+        lld-12 \
+        llvm-12 \
+        llvm-12-dev \
         moreutils \
         ninja-build \
         perl \
diff --git a/docker/packager/packager b/docker/packager/packager
index 673878bce43..f37d64e9949 100755
--- a/docker/packager/packager
+++ b/docker/packager/packager
@@ -75,7 +75,7 @@ def parse_env_variables(build_type, compiler, sanitizer, package_type, image_typ
     # Explicitly use LLD with Clang by default.
     # Don't force linker for cross-compilation.
     if is_clang and not is_cross_compile:
-        cmake_flags.append("-DLINKER_NAME=lld")
+        cmake_flags.append("-DLINKER_NAME=ld.lld")
 
     if is_cross_darwin:
         cc = compiler[:-len(DARWIN_SUFFIX)]
@@ -204,7 +204,8 @@ if __name__ == "__main__":
     parser.add_argument("--output-dir", required=True)
     parser.add_argument("--build-type", choices=("debug", ""), default="")
     parser.add_argument("--compiler", choices=("clang-11", "clang-11-darwin", "clang-11-darwin-aarch64", "clang-11-aarch64",
-                                               "clang-11-freebsd", "gcc-10"), default="clang-11")
+                                               "clang-12", "clang-12-darwin", "clang-12-darwin-aarch64", "clang-12-aarch64",
+                                               "clang-11-freebsd", "clang-12-freebsd", "gcc-10"), default="clang-12")
     parser.add_argument("--sanitizer", choices=("address", "thread", "memory", "undefined", ""), default="")
     parser.add_argument("--unbundled", action="store_true")
     parser.add_argument("--split-binary", action="store_true")
diff --git a/docker/test/base/Dockerfile b/docker/test/base/Dockerfile
index 611ef6b7702..88c9e1ae06e 100644
--- a/docker/test/base/Dockerfile
+++ b/docker/test/base/Dockerfile
@@ -1,7 +1,7 @@
 # docker build -t yandex/clickhouse-test-base .
 FROM ubuntu:20.04
 
-ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=11
+ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=12
 
 RUN sed -i 's|http://archive|http://ru.archive|g' /etc/apt/sources.list
 
diff --git a/docker/test/codebrowser/Dockerfile b/docker/test/codebrowser/Dockerfile
index 33173ab90f9..ae2aafa76c8 100644
--- a/docker/test/codebrowser/Dockerfile
+++ b/docker/test/codebrowser/Dockerfile
@@ -11,7 +11,7 @@ RUN apt-get update && apt-get --yes --allow-unauthenticated install clang-9 libl
 # https://github.com/ClickHouse-Extras/woboq_codebrowser/commit/37e15eaf377b920acb0b48dbe82471be9203f76b
 RUN git clone https://github.com/ClickHouse-Extras/woboq_codebrowser
 
-RUN cd woboq_codebrowser && cmake . -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang\+\+-9 -DCMAKE_C_COMPILER=clang-9 && make -j
+RUN cd woboq_codebrowser && cmake . -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang\+\+-12 -DCMAKE_C_COMPILER=clang-12 && make -j
 
 ENV CODEGEN=/woboq_codebrowser/generator/codebrowser_generator
 ENV CODEINDEX=/woboq_codebrowser/indexgenerator/codebrowser_indexgenerator
@@ -24,7 +24,7 @@ ENV SHA=nosha
 ENV DATA="data"
 
 CMD mkdir -p $BUILD_DIRECTORY && cd $BUILD_DIRECTORY && \
-    cmake $SOURCE_DIRECTORY -DCMAKE_CXX_COMPILER=/usr/bin/clang\+\+-11 -DCMAKE_C_COMPILER=/usr/bin/clang-11 -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DENABLE_EMBEDDED_COMPILER=0 -DENABLE_S3=0 && \
+    cmake $SOURCE_DIRECTORY -DCMAKE_CXX_COMPILER=/usr/bin/clang\+\+-12 -DCMAKE_C_COMPILER=/usr/bin/clang-12 -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DENABLE_EMBEDDED_COMPILER=0 -DENABLE_S3=0 && \
     mkdir -p $HTML_RESULT_DIRECTORY && \
     $CODEGEN -b $BUILD_DIRECTORY -a -o $HTML_RESULT_DIRECTORY -p ClickHouse:$SOURCE_DIRECTORY:$SHA -d $DATA | ts '%Y-%m-%d %H:%M:%S' && \
     cp -r $STATIC_DATA $HTML_RESULT_DIRECTORY/ &&\
diff --git a/docker/test/fasttest/Dockerfile b/docker/test/fasttest/Dockerfile
index 2e0bbcd350f..9443cbf496e 100644
--- a/docker/test/fasttest/Dockerfile
+++ b/docker/test/fasttest/Dockerfile
@@ -1,7 +1,7 @@
 #  docker build -t yandex/clickhouse-fasttest .
 FROM ubuntu:20.04
 
-ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=11
+ENV DEBIAN_FRONTEND=noninteractive LLVM_VERSION=12
 
 RUN sed -i 's|http://archive|http://ru.archive|g' /etc/apt/sources.list
 
diff --git a/docker/test/fasttest/run.sh b/docker/test/fasttest/run.sh
index ed7e72de2a9..8a6b7f70cba 100755
--- a/docker/test/fasttest/run.sh
+++ b/docker/test/fasttest/run.sh
@@ -9,7 +9,7 @@ trap 'kill $(jobs -pr) ||:' EXIT
 stage=${stage:-}
 
 # Compiler version, normally set by Dockerfile
-export LLVM_VERSION=${LLVM_VERSION:-11}
+export LLVM_VERSION=${LLVM_VERSION:-12}
 
 # A variable to pass additional flags to CMake.
 # Here we explicitly default it to nothing so that bash doesn't complain about
diff --git a/docker/test/fuzzer/run-fuzzer.sh b/docker/test/fuzzer/run-fuzzer.sh
index 603c35ede54..2247c6a22be 100755
--- a/docker/test/fuzzer/run-fuzzer.sh
+++ b/docker/test/fuzzer/run-fuzzer.sh
@@ -12,7 +12,7 @@ stage=${stage:-}
 script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 echo "$script_dir"
 repo_dir=ch
-BINARY_TO_DOWNLOAD=${BINARY_TO_DOWNLOAD:="clang-11_debug_none_bundled_unsplitted_disable_False_binary"}
+BINARY_TO_DOWNLOAD=${BINARY_TO_DOWNLOAD:="clang-12_debug_none_bundled_unsplitted_disable_False_binary"}
 
 function clone
 {
diff --git a/docker/test/keeper-jepsen/run.sh b/docker/test/keeper-jepsen/run.sh
index 352585e16e3..8d31b5b7f1c 100644
--- a/docker/test/keeper-jepsen/run.sh
+++ b/docker/test/keeper-jepsen/run.sh
@@ -2,7 +2,7 @@
 set -euo pipefail
 
 
-CLICKHOUSE_PACKAGE=${CLICKHOUSE_PACKAGE:="https://clickhouse-builds.s3.yandex.net/$PR_TO_TEST/$SHA_TO_TEST/clickhouse_build_check/clang-11_relwithdebuginfo_none_bundled_unsplitted_disable_False_binary/clickhouse"}
+CLICKHOUSE_PACKAGE=${CLICKHOUSE_PACKAGE:="https://clickhouse-builds.s3.yandex.net/$PR_TO_TEST/$SHA_TO_TEST/clickhouse_build_check/clang-12_relwithdebuginfo_none_bundled_unsplitted_disable_False_binary/clickhouse"}
 CLICKHOUSE_REPO_PATH=${CLICKHOUSE_REPO_PATH:=""}
 
 
diff --git a/docker/test/pvs/Dockerfile b/docker/test/pvs/Dockerfile
index 7bd45ba4018..438f0bd07ec 100644
--- a/docker/test/pvs/Dockerfile
+++ b/docker/test/pvs/Dockerfile
@@ -28,7 +28,7 @@ RUN apt-get update --yes \
 ENV PKG_VERSION="pvs-studio-latest"
 
 RUN set -x \
-    && export PUBKEY_HASHSUM="686e5eb8b3c543a5c54442c39ec876b6c2d912fe8a729099e600017ae53c877dda3368fe38ed7a66024fe26df6b5892a" \
+    && export PUBKEY_HASHSUM="ad369a2e9d8b8c30f5a9f2eb131121739b79c78e03fef0f016ea51871a5f78cd4e6257b270dca0ac3be3d1f19d885516" \
     && wget -nv https://files.viva64.com/etc/pubkey.txt -O /tmp/pubkey.txt \
     && echo "${PUBKEY_HASHSUM} /tmp/pubkey.txt" | sha384sum -c \
     && apt-key add /tmp/pubkey.txt \
@@ -38,7 +38,7 @@ RUN set -x \
     && dpkg -i "${PKG_VERSION}.deb"
 
 CMD echo "Running PVS version $PKG_VERSION" && cd /repo_folder && pvs-studio-analyzer credentials $LICENCE_NAME $LICENCE_KEY -o ./licence.lic  \
-    && cmake . -D"ENABLE_EMBEDDED_COMPILER"=OFF -D"USE_INTERNAL_PROTOBUF_LIBRARY"=OFF -D"USE_INTERNAL_GRPC_LIBRARY"=OFF \
+    && cmake . -D"ENABLE_EMBEDDED_COMPILER"=OFF -D"USE_INTERNAL_PROTOBUF_LIBRARY"=OFF -D"USE_INTERNAL_GRPC_LIBRARY"=OFF -DCMAKE_C_COMPILER=clang-12 -DCMAKE_CXX_COMPILER=clang\+\+-12 \
     && ninja re2_st clickhouse_grpc_protos \
     && pvs-studio-analyzer analyze -o pvs-studio.log -e contrib -j 4 -l ./licence.lic; \
     cp /repo_folder/pvs-studio.log /test_output; \
diff --git a/docs/en/development/build.md b/docs/en/development/build.md
index be45c1ed5f7..8d1aae13957 100644
--- a/docs/en/development/build.md
+++ b/docs/en/development/build.md
@@ -23,7 +23,7 @@ $ sudo apt-get install git cmake python ninja-build
 
 Or cmake3 instead of cmake on older systems.
 
-### Install clang-11 (recommended) {#install-clang-11}
+### Install clang-12 (recommended) {#install-clang-12}
 
 On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
@@ -33,11 +33,11 @@ sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
 
 For other Linux distribution - check the availability of the [prebuild packages](https://releases.llvm.org/download.html) or build clang [from sources](https://clang.llvm.org/get_started.html).
 
-#### Use clang-11 for Builds
+#### Use clang-12 for Builds
 
 ``` bash
-$ export CC=clang-11
-$ export CXX=clang++-11
+$ export CC=clang-12
+$ export CXX=clang++-12
 ```
 
 Gcc can also be used though it is discouraged.
diff --git a/src/Common/FiberStack.h b/src/Common/FiberStack.h
index c509540cc9e..aec4befb515 100644
--- a/src/Common/FiberStack.h
+++ b/src/Common/FiberStack.h
@@ -27,7 +27,12 @@ private:
     size_t stack_size;
     size_t page_size = 0;
 public:
-    static constexpr size_t default_stack_size = 128 * 1024; /// 64KB was not enough for tests
+    /// NOTE: If you see random segfaults in CI and stack starts from boost::context::...fiber...
+    /// probably it worth to try to increase stack size for coroutines.
+    ///
+    /// Current value is just enough for all tests in our CI. It's not selected in some special
+    /// way. We will have 36 pages with 4KB page size.
+    static constexpr size_t default_stack_size = 144 * 1024; /// 64KB was not enough for tests
 
     explicit FiberStack(size_t stack_size_ = default_stack_size) : stack_size(stack_size_)
     {
@@ -43,6 +48,8 @@ public:
         if (MAP_FAILED == vp)
             DB::throwFromErrno(fmt::format("FiberStack: Cannot mmap {}.", ReadableSize(num_bytes)), DB::ErrorCodes::CANNOT_ALLOCATE_MEMORY);
 
+        /// TODO: make reports on illegal guard page access more clear.
+        /// Currently we will see segfault and almost random stacktrace.
         if (-1 == ::mprotect(vp, page_size, PROT_NONE))
         {
             ::munmap(vp, num_bytes);
diff --git a/src/Compression/CompressionCodecEncrypted.cpp b/src/Compression/CompressionCodecEncrypted.cpp
index 6b921fb9c0a..47f93eb6202 100644
--- a/src/Compression/CompressionCodecEncrypted.cpp
+++ b/src/Compression/CompressionCodecEncrypted.cpp
@@ -113,7 +113,8 @@ namespace DB
 
     std::string CompressionCodecEncrypted::deriveKey(const std::string_view & master_key)
     {
-        std::string_view salt(""); // No salt: derive keys in a deterministic manner.
+        /// No salt: derive keys in a deterministic manner.
+        std::string_view salt(""); // NOLINT
         std::string_view info("Codec Encrypted('AES-128-GCM-SIV') key generation key");
         std::array<char, 32> result;
 
diff --git a/src/IO/WriteBufferFromFile.cpp b/src/IO/WriteBufferFromFile.cpp
index 67cd7ba27d6..270882d0774 100644
--- a/src/IO/WriteBufferFromFile.cpp
+++ b/src/IO/WriteBufferFromFile.cpp
@@ -32,7 +32,7 @@ WriteBufferFromFile::WriteBufferFromFile(
     mode_t mode,
     char * existing_memory,
     size_t alignment)
-    : WriteBufferFromFileDescriptor(-1, buf_size, existing_memory, alignment), file_name(file_name_)
+    : WriteBufferFromFileDescriptor(-1, buf_size, existing_memory, alignment, file_name_)
 {
     ProfileEvents::increment(ProfileEvents::FileOpen);
 
@@ -65,9 +65,7 @@ WriteBufferFromFile::WriteBufferFromFile(
     size_t buf_size,
     char * existing_memory,
     size_t alignment)
-    :
-    WriteBufferFromFileDescriptor(fd_, buf_size, existing_memory, alignment),
-    file_name(original_file_name.empty() ? "(fd = " + toString(fd_) + ")" : original_file_name)
+    : WriteBufferFromFileDescriptor(fd_, buf_size, existing_memory, alignment, original_file_name)
 {
     fd_ = -1;
 }
diff --git a/src/IO/WriteBufferFromFile.h b/src/IO/WriteBufferFromFile.h
index b7d58638113..584a0221f1a 100644
--- a/src/IO/WriteBufferFromFile.h
+++ b/src/IO/WriteBufferFromFile.h
@@ -25,7 +25,6 @@ namespace DB
 class WriteBufferFromFile : public WriteBufferFromFileDescriptor
 {
 protected:
-    std::string file_name;
     CurrentMetrics::Increment metric_increment{CurrentMetrics::OpenFileForWrite};
 
 public:
diff --git a/src/IO/WriteBufferFromFileDescriptor.cpp b/src/IO/WriteBufferFromFileDescriptor.cpp
index cd265653bb9..38aaa945362 100644
--- a/src/IO/WriteBufferFromFileDescriptor.cpp
+++ b/src/IO/WriteBufferFromFileDescriptor.cpp
@@ -61,7 +61,12 @@ void WriteBufferFromFileDescriptor::nextImpl()
         if ((-1 == res || 0 == res) && errno != EINTR)
         {
             ProfileEvents::increment(ProfileEvents::WriteBufferFromFileDescriptorWriteFailed);
-            throwFromErrnoWithPath("Cannot write to file " + getFileName(), getFileName(),
+
+            /// Don't use getFileName() here because this method can be called from destructor
+            String error_file_name = file_name;
+            if (error_file_name.empty())
+                error_file_name = "(fd = " + toString(fd) + ")";
+            throwFromErrnoWithPath("Cannot write to file " + error_file_name, error_file_name,
                                    ErrorCodes::CANNOT_WRITE_TO_FILE_DESCRIPTOR);
         }
 
@@ -73,20 +78,20 @@ void WriteBufferFromFileDescriptor::nextImpl()
     ProfileEvents::increment(ProfileEvents::WriteBufferFromFileDescriptorWriteBytes, bytes_written);
 }
 
-
-/// Name or some description of file.
-std::string WriteBufferFromFileDescriptor::getFileName() const
-{
-    return "(fd = " + toString(fd) + ")";
-}
-
-
+/// NOTE: This class can be used as a very low-level building block, for example
+/// in trace collector. In such places allocations of memory can be dangerous,
+/// so don't allocate anything in this constructor.
 WriteBufferFromFileDescriptor::WriteBufferFromFileDescriptor(
     int fd_,
     size_t buf_size,
     char * existing_memory,
-    size_t alignment)
-    : WriteBufferFromFileBase(buf_size, existing_memory, alignment), fd(fd_) {}
+    size_t alignment,
+    std::string file_name_)
+    : WriteBufferFromFileBase(buf_size, existing_memory, alignment)
+    , fd(fd_)
+    , file_name(std::move(file_name_))
+{
+}
 
 
 WriteBufferFromFileDescriptor::~WriteBufferFromFileDescriptor()
@@ -115,7 +120,7 @@ void WriteBufferFromFileDescriptor::sync()
 }
 
 
-off_t WriteBufferFromFileDescriptor::seek(off_t offset, int whence)
+off_t WriteBufferFromFileDescriptor::seek(off_t offset, int whence) // NOLINT
 {
     off_t res = lseek(fd, offset, whence);
     if (-1 == res)
@@ -125,7 +130,7 @@ off_t WriteBufferFromFileDescriptor::seek(off_t offset, int whence)
 }
 
 
-void WriteBufferFromFileDescriptor::truncate(off_t length)
+void WriteBufferFromFileDescriptor::truncate(off_t length) // NOLINT
 {
     int res = ftruncate(fd, length);
     if (-1 == res)
@@ -133,7 +138,7 @@ void WriteBufferFromFileDescriptor::truncate(off_t length)
 }
 
 
-off_t WriteBufferFromFileDescriptor::size()
+off_t WriteBufferFromFileDescriptor::size() const
 {
     struct stat buf;
     int res = fstat(fd, &buf);
@@ -142,4 +147,13 @@ off_t WriteBufferFromFileDescriptor::size()
     return buf.st_size;
 }
 
+std::string WriteBufferFromFileDescriptor::getFileName() const
+{
+    if (file_name.empty())
+        return "(fd = " + toString(fd) + ")";
+
+    return file_name;
+}
+
+
 }
diff --git a/src/IO/WriteBufferFromFileDescriptor.h b/src/IO/WriteBufferFromFileDescriptor.h
index 18c0ac64f63..cad45067548 100644
--- a/src/IO/WriteBufferFromFileDescriptor.h
+++ b/src/IO/WriteBufferFromFileDescriptor.h
@@ -13,17 +13,17 @@ class WriteBufferFromFileDescriptor : public WriteBufferFromFileBase
 protected:
     int fd;
 
+    /// If file has name contains filename, otherwise contains string "(fd=...)"
+    std::string file_name;
+
     void nextImpl() override;
-
-    /// Name or some description of file.
-    std::string getFileName() const override;
-
 public:
     WriteBufferFromFileDescriptor(
         int fd_ = -1,
         size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
         char * existing_memory = nullptr,
-        size_t alignment = 0);
+        size_t alignment = 0,
+        std::string file_name_ = "");
 
     /** Could be used before initialization if needed 'fd' was not passed to constructor.
       * It's not possible to change 'fd' during work.
@@ -42,10 +42,15 @@ public:
 
     void sync() override;
 
-    off_t seek(off_t offset, int whence);
-    void truncate(off_t length);
+    /// clang-tidy wants these methods to be const, but
+    /// they are not const semantically
+    off_t seek(off_t offset, int whence); // NOLINT
+    void truncate(off_t length); // NOLINT
 
-    off_t size();
+    /// Name or some description of file.
+    std::string getFileName() const override;
+
+    off_t size() const;
 };
 
 }
diff --git a/src/Interpreters/LogicalExpressionsOptimizer.cpp b/src/Interpreters/LogicalExpressionsOptimizer.cpp
index c0d5a16fa65..936ed0149d2 100644
--- a/src/Interpreters/LogicalExpressionsOptimizer.cpp
+++ b/src/Interpreters/LogicalExpressionsOptimizer.cpp
@@ -225,22 +225,19 @@ void LogicalExpressionsOptimizer::addInExpression(const DisjunctiveEqualityChain
 
     /// 1. Create a new IN expression based on information from the OR-chain.
 
-    /// Construct a list of literals `x1, ..., xN` from the string `expr = x1 OR ... OR expr = xN`
-    ASTPtr value_list = std::make_shared<ASTExpressionList>();
+    /// Construct a tuple of literals `x1, ..., xN` from the string `expr = x1 OR ... OR expr = xN`
+
+    Tuple tuple;
+    tuple.reserve(equality_functions.size());
+
     for (const auto * function : equality_functions)
     {
         const auto & operands = getFunctionOperands(function);
-        value_list->children.push_back(operands[1]);
+        tuple.push_back(operands[1]->as<ASTLiteral>()->value);
     }
 
     /// Sort the literals so that they are specified in the same order in the IN expression.
-    /// Otherwise, they would be specified in the order of the ASTLiteral addresses, which is nondeterministic.
-    std::sort(value_list->children.begin(), value_list->children.end(), [](const DB::ASTPtr & lhs, const DB::ASTPtr & rhs)
-    {
-        const auto * val_lhs = lhs->as<ASTLiteral>();
-        const auto * val_rhs = rhs->as<ASTLiteral>();
-        return val_lhs->value < val_rhs->value;
-    });
+    std::sort(tuple.begin(), tuple.end());
 
     /// Get the expression `expr` from the chain `expr = x1 OR ... OR expr = xN`
     ASTPtr equals_expr_lhs;
@@ -250,14 +247,11 @@ void LogicalExpressionsOptimizer::addInExpression(const DisjunctiveEqualityChain
         equals_expr_lhs = operands[0];
     }
 
-    auto tuple_function = std::make_shared<ASTFunction>();
-    tuple_function->name = "tuple";
-    tuple_function->arguments = value_list;
-    tuple_function->children.push_back(tuple_function->arguments);
+    auto tuple_literal = std::make_shared<ASTLiteral>(std::move(tuple));
 
     ASTPtr expression_list = std::make_shared<ASTExpressionList>();
     expression_list->children.push_back(equals_expr_lhs);
-    expression_list->children.push_back(tuple_function);
+    expression_list->children.push_back(tuple_literal);
 
     /// Construct the expression `expr IN (x1, ..., xN)`
     auto in_function = std::make_shared<ASTFunction>();
diff --git a/src/Storages/StorageDistributed.cpp b/src/Storages/StorageDistributed.cpp
index df7d568deb9..1ad80f8aea6 100644
--- a/src/Storages/StorageDistributed.cpp
+++ b/src/Storages/StorageDistributed.cpp
@@ -1332,7 +1332,12 @@ void registerStorageDistributed(StorageFactory & factory)
         String remote_table = engine_args[2]->as<ASTLiteral &>().value.safeGet<String>();
 
         const auto & sharding_key = engine_args.size() >= 4 ? engine_args[3] : nullptr;
-        const auto & storage_policy = engine_args.size() >= 5 ? engine_args[4]->as<ASTLiteral &>().value.safeGet<String>() : "default";
+        String storage_policy = "default";
+        if (engine_args.size() >= 5)
+        {
+            engine_args[4] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[4], local_context);
+            storage_policy = engine_args[4]->as<ASTLiteral &>().value.safeGet<String>();
+        }
 
         /// Check that sharding_key exists in the table and has numeric type.
         if (sharding_key)
diff --git a/src/Storages/ya.make b/src/Storages/ya.make
index 5b246cf5aca..11a1ad212c1 100644
--- a/src/Storages/ya.make
+++ b/src/Storages/ya.make
@@ -214,7 +214,6 @@ SRCS(
     System/StorageSystemTables.cpp
     System/StorageSystemUserDirectories.cpp
     System/StorageSystemUsers.cpp
-    System/StorageSystemViews.cpp
     System/StorageSystemWarnings.cpp
     System/StorageSystemZeros.cpp
     System/StorageSystemZooKeeper.cpp
diff --git a/tests/ci/ci_config.json b/tests/ci/ci_config.json
index 52a101728ea..26c8d560312 100644
--- a/tests/ci/ci_config.json
+++ b/tests/ci/ci_config.json
@@ -1,7 +1,7 @@
 {
     "build_config": [
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "",
             "package-type": "deb",
@@ -12,7 +12,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "",
             "package-type": "performance",
@@ -32,7 +32,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "address",
             "package-type": "deb",
@@ -42,7 +42,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "undefined",
             "package-type": "deb",
@@ -52,7 +52,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "thread",
             "package-type": "deb",
@@ -62,7 +62,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "memory",
             "package-type": "deb",
@@ -72,7 +72,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "debug",
             "sanitizer": "",
             "package-type": "deb",
@@ -92,7 +92,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "",
             "package-type": "binary",
@@ -104,7 +104,7 @@
     ],
     "special_build_config": [
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "debug",
             "sanitizer": "",
             "package-type": "deb",
@@ -114,7 +114,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11",
+            "compiler": "clang-12",
             "build-type": "",
             "sanitizer": "",
             "package-type": "binary",
@@ -124,7 +124,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11-darwin",
+            "compiler": "clang-12-darwin",
             "build-type": "",
             "sanitizer": "",
             "package-type": "binary",
@@ -134,7 +134,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11-aarch64",
+            "compiler": "clang-12-aarch64",
             "build-type": "",
             "sanitizer": "",
             "package-type": "binary",
@@ -144,7 +144,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11-freebsd",
+            "compiler": "clang-12-freebsd",
             "build-type": "",
             "sanitizer": "",
             "package-type": "binary",
@@ -154,7 +154,7 @@
             "with_coverage": false
         },
         {
-            "compiler": "clang-11-darwin-aarch64",
+            "compiler": "clang-12-darwin-aarch64",
             "build-type": "",
             "sanitizer": "",
             "package-type": "binary",
@@ -167,7 +167,7 @@
     "tests_config": {
         "Functional stateful tests (address)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -179,7 +179,7 @@
         },
         "Functional stateful tests (thread)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -191,7 +191,7 @@
         },
         "Functional stateful tests (memory)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "memory",
@@ -203,7 +203,7 @@
         },
         "Functional stateful tests (ubsan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "undefined",
@@ -215,7 +215,7 @@
         },
         "Functional stateful tests (debug)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "debug",
                 "sanitizer": "none",
@@ -227,7 +227,7 @@
         },
         "Functional stateful tests (release)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -239,7 +239,7 @@
         },
         "Functional stateful tests (release, DatabaseOrdinary)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -251,7 +251,7 @@
         },
         "Functional stateful tests (release, DatabaseReplicated)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -263,7 +263,7 @@
         },
         "Functional stateless tests (address)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -275,7 +275,7 @@
         },
         "Functional stateless tests (thread)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -287,7 +287,7 @@
         },
         "Functional stateless tests (memory)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "memory",
@@ -299,7 +299,7 @@
         },
         "Functional stateless tests (ubsan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "undefined",
@@ -311,7 +311,7 @@
         },
         "Functional stateless tests (debug)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "debug",
                 "sanitizer": "none",
@@ -323,7 +323,7 @@
         },
         "Functional stateless tests (release)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -335,7 +335,7 @@
         },
         "Functional stateless tests (pytest)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -359,7 +359,7 @@
         },
         "Functional stateless tests (release, wide parts enabled)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -371,7 +371,7 @@
         },
         "Functional stateless tests (release, DatabaseOrdinary)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -383,7 +383,7 @@
         },
         "Functional stateless tests (release, DatabaseReplicated)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -395,7 +395,7 @@
         },
         "Stress test (address)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -407,7 +407,7 @@
         },
         "Stress test (thread)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -419,7 +419,7 @@
         },
         "Stress test (undefined)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "undefined",
@@ -431,7 +431,7 @@
         },
         "Stress test (memory)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "memory",
@@ -443,7 +443,7 @@
         },
         "Stress test (debug)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "debug",
                 "sanitizer": "none",
@@ -455,7 +455,7 @@
         },
         "Integration tests (asan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -467,7 +467,7 @@
         },
         "Integration tests (thread)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -479,7 +479,7 @@
         },
         "Integration tests (release)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -491,7 +491,7 @@
         },
         "Integration tests (memory)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "memory",
@@ -503,7 +503,7 @@
         },
         "Integration tests flaky check (asan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -515,7 +515,7 @@
         },
         "Compatibility check": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -527,7 +527,7 @@
         },
         "Split build smoke test": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -539,7 +539,7 @@
         },
         "Testflows check": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -563,7 +563,7 @@
         },
         "Unit tests release clang": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -575,7 +575,7 @@
         },
         "Unit tests ASAN": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -587,7 +587,7 @@
         },
         "Unit tests MSAN": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "memory",
@@ -599,7 +599,7 @@
         },
         "Unit tests TSAN": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -611,7 +611,7 @@
         },
         "Unit tests UBSAN": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -623,7 +623,7 @@
         },
         "AST fuzzer (debug)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "debug",
                 "sanitizer": "none",
@@ -635,7 +635,7 @@
         },
         "AST fuzzer (ASan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
@@ -647,7 +647,7 @@
         },
         "AST fuzzer (MSan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "memory",
@@ -659,7 +659,7 @@
         },
         "AST fuzzer (TSan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "thread",
@@ -671,7 +671,7 @@
         },
         "AST fuzzer (UBSan)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "binary",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "undefined",
@@ -683,7 +683,7 @@
         },
         "Release": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "none",
@@ -695,7 +695,7 @@
         },
         "Functional stateless tests flaky check (address)": {
             "required_build_properties": {
-                "compiler": "clang-11",
+                "compiler": "clang-12",
                 "package_type": "deb",
                 "build_type": "relwithdebuginfo",
                 "sanitizer": "address",
diff --git a/tests/queries/0_stateless/02015_shard_crash_clang_12_build.reference b/tests/queries/0_stateless/02015_shard_crash_clang_12_build.reference
new file mode 100644
index 00000000000..d00491fd7e5
--- /dev/null
+++ b/tests/queries/0_stateless/02015_shard_crash_clang_12_build.reference
@@ -0,0 +1 @@
+1
diff --git a/tests/queries/0_stateless/02015_shard_crash_clang_12_build.sh b/tests/queries/0_stateless/02015_shard_crash_clang_12_build.sh
new file mode 100755
index 00000000000..f6ede6592ff
--- /dev/null
+++ b/tests/queries/0_stateless/02015_shard_crash_clang_12_build.sh
@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+
+# This test reproduces crash in case of insufficient coroutines stack size
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CURDIR"/../shell_config.sh
+
+
+$CLICKHOUSE_CLIENT --query "DROP TABLE IF EXISTS local"
+$CLICKHOUSE_CLIENT --query "DROP TABLE IF EXISTS distributed"
+
+$CLICKHOUSE_CLIENT --query "CREATE TABLE local (x UInt8) ENGINE = Memory;"
+$CLICKHOUSE_CLIENT --query "CREATE TABLE distributed AS local ENGINE = Distributed(test_cluster_two_shards, currentDatabase(), local, x);"
+
+$CLICKHOUSE_CLIENT --insert_distributed_sync=0 --network_compression_method='zstd' --query "INSERT INTO distributed SELECT number FROM numbers(256);"
+$CLICKHOUSE_CLIENT --insert_distributed_sync=0 --network_compression_method='zstd' --query "SYSTEM FLUSH DISTRIBUTED distributed;"
+
+function select_thread()
+{
+    while true; do
+        $CLICKHOUSE_CLIENT --insert_distributed_sync=0 --network_compression_method='zstd' --query "SELECT count() FROM local" >/dev/null
+        $CLICKHOUSE_CLIENT --insert_distributed_sync=0 --network_compression_method='zstd' --query "SELECT count() FROM distributed" >/dev/null
+    done
+}
+
+export -f select_thread;
+
+TIMEOUT=30
+
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+timeout $TIMEOUT bash -c select_thread 2> /dev/null &
+
+wait
+
+$CLICKHOUSE_CLIENT --query "SELECT 1"
+
+$CLICKHOUSE_CLIENT --query "DROP TABLE IF EXISTS local"
+$CLICKHOUSE_CLIENT --query "DROP TABLE IF EXISTS distributed"
diff --git a/tests/queries/0_stateless/02017_create_distributed_table_coredump.reference b/tests/queries/0_stateless/02017_create_distributed_table_coredump.reference
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/queries/0_stateless/02017_create_distributed_table_coredump.sql b/tests/queries/0_stateless/02017_create_distributed_table_coredump.sql
new file mode 100644
index 00000000000..27c98c3e237
--- /dev/null
+++ b/tests/queries/0_stateless/02017_create_distributed_table_coredump.sql
@@ -0,0 +1,12 @@
+drop table if exists t;
+drop table if exists td1;
+drop table if exists td2;
+drop table if exists td3;
+create table t (val UInt32) engine = MergeTree order by val;
+create table td1 engine = Distributed(test_shard_localhost, currentDatabase(), 't') as t;
+create table td2 engine = Distributed(test_shard_localhost, currentDatabase(), 't', xxHash32(val), default) as t;
+create table td3 engine = Distributed(test_shard_localhost, currentDatabase(), 't', xxHash32(val), 'default') as t;
+drop table if exists t;
+drop table if exists td1; 
+drop table if exists td2; 
+drop table if exists td3; 
diff --git a/tests/queries/0_stateless/02023_transform_or_to_in.reference b/tests/queries/0_stateless/02023_transform_or_to_in.reference
new file mode 100644
index 00000000000..aa47d0d46d4
--- /dev/null
+++ b/tests/queries/0_stateless/02023_transform_or_to_in.reference
@@ -0,0 +1,2 @@
+0
+0
diff --git a/tests/queries/0_stateless/02023_transform_or_to_in.sql b/tests/queries/0_stateless/02023_transform_or_to_in.sql
new file mode 100644
index 00000000000..c4ceeb76931
--- /dev/null
+++ b/tests/queries/0_stateless/02023_transform_or_to_in.sql
@@ -0,0 +1,15 @@
+DROP TABLE IF EXISTS t_transform_or;
+
+CREATE TABLE t_transform_or(B AggregateFunction(uniq, String), A String) Engine=MergeTree ORDER BY (A);
+
+INSERT INTO t_transform_or SELECT uniqState(''), '0';
+
+SELECT uniqMergeIf(B, (A = '1') OR (A = '2') OR (A = '3'))
+FROM cluster(test_cluster_two_shards, currentDatabase(), t_transform_or)
+SETTINGS legacy_column_name_of_tuple_literal = 0;
+
+SELECT uniqMergeIf(B, (A = '1') OR (A = '2') OR (A = '3'))
+FROM cluster(test_cluster_two_shards, currentDatabase(), t_transform_or)
+SETTINGS legacy_column_name_of_tuple_literal = 1;
+
+DROP TABLE t_transform_or;