Merge branch 'master' of github.com:ClickHouse/ClickHouse into system-symbols

contrib/grpc

@@ -1 +1 @@
-Subproject commit 267af8c3a1ea4a5a4d9e5a070ad2d1ac7c701923
+Subproject commit b723ecae0991bb873fe87a595dfb187178733fde

contrib/sparse-checkout/update-grpc.sh

@@ -7,6 +7,7 @@ echo '/*' > $FILES_TO_CHECKOUT
 echo '!/test/*' >> $FILES_TO_CHECKOUT
 echo '/test/build/*' >> $FILES_TO_CHECKOUT
 echo '/test/core/tsi/alts/fake_handshaker/*' >> $FILES_TO_CHECKOUT
+echo '/test/core/event_engine/fuzzing_event_engine/*' >> $FILES_TO_CHECKOUT
 echo '!/tools/*' >> $FILES_TO_CHECKOUT
 echo '/tools/codegen/*' >> $FILES_TO_CHECKOUT
 echo '!/examples/*' >> $FILES_TO_CHECKOUT

docker/test/base/setup_export_logs.sh

@@ -19,6 +19,11 @@ EXTRA_COLUMNS=${EXTRA_COLUMNS:-"pull_request_number UInt32, commit_sha String, c
 EXTRA_COLUMNS_EXPRESSION=${EXTRA_COLUMNS_EXPRESSION:-"CAST(0 AS UInt32) AS pull_request_number, '' AS commit_sha, now() AS check_start_time, toLowCardinality('') AS check_name, toLowCardinality('') AS instance_type, '' AS instance_id"}
 EXTRA_ORDER_BY_COLUMNS=${EXTRA_ORDER_BY_COLUMNS:-"check_name, "}
 
+# trace_log needs more columns for symbolization
+EXTRA_COLUMNS_TRACE_LOG="${EXTRA_COLUMNS} symbols Array(LowCardinality(String)), lines Array(LowCardinality(String)), "
+EXTRA_COLUMNS_EXPRESSION_TRACE_LOG="${EXTRA_COLUMNS_EXPRESSION}, arrayMap(x -> toLowCardinality(demangle(addressToSymbol(x))), trace) AS symbols, arrayMap(x -> toLowCardinality(addressToLine(x)), trace) AS lines"
+
+
 function __set_connection_args
 {
     # It's impossible to use generous $CONNECTION_ARGS string, it's unsafe from word splitting perspective.
@@ -125,9 +130,18 @@ function setup_logs_replication
     echo 'Create %_log tables'
     clickhouse-client --query "SHOW TABLES FROM system LIKE '%\\_log'" | while read -r table
     do
+        if [[ "$table" = "trace_log" ]]
+        then
+            EXTRA_COLUMNS_FOR_TABLE="${EXTRA_COLUMNS_TRACE_LOG}"
+            EXTRA_COLUMNS_EXPRESSION_FOR_TABLE="${EXTRA_COLUMNS_EXPRESSION_TRACE_LOG}"
+        else
+            EXTRA_COLUMNS_FOR_TABLE="${EXTRA_COLUMNS}"
+            EXTRA_COLUMNS_EXPRESSION_FOR_TABLE="${EXTRA_COLUMNS_EXPRESSION}"
+        fi
+
         # Calculate hash of its structure. Note: 4 is the version of extra columns - increment it if extra columns are changed:
         hash=$(clickhouse-client --query "
-            SELECT sipHash64(7, groupArray((name, type)))
+            SELECT sipHash64(9, groupArray((name, type)))
             FROM (SELECT name, type FROM system.columns
                 WHERE database = 'system' AND table = '$table'
                 ORDER BY position)
@@ -135,7 +149,7 @@ function setup_logs_replication
 
         # Create the destination table with adapted name and structure:
         statement=$(clickhouse-client --format TSVRaw --query "SHOW CREATE TABLE system.${table}" | sed -r -e '
-            s/^\($/('"$EXTRA_COLUMNS"'/;
+            s/^\($/('"$EXTRA_COLUMNS_FOR_TABLE"'/;
             s/ORDER BY \(/ORDER BY ('"$EXTRA_ORDER_BY_COLUMNS"'/;
             s/^CREATE TABLE system\.\w+_log$/CREATE TABLE IF NOT EXISTS '"$table"'_'"$hash"'/;
             /^TTL /d
@@ -155,7 +169,7 @@ function setup_logs_replication
             ENGINE = Distributed(${CLICKHOUSE_CI_LOGS_CLUSTER}, default, ${table}_${hash})
             SETTINGS flush_on_detach=0
             EMPTY AS
-            SELECT ${EXTRA_COLUMNS_EXPRESSION}, *
+            SELECT ${EXTRA_COLUMNS_EXPRESSION_FOR_TABLE}, *
             FROM system.${table}
         " || continue
 
@@ -163,7 +177,7 @@ function setup_logs_replication
 
         clickhouse-client --query "
             CREATE MATERIALIZED VIEW system.${table}_watcher TO system.${table}_sender AS
-            SELECT ${EXTRA_COLUMNS_EXPRESSION}, *
+            SELECT ${EXTRA_COLUMNS_EXPRESSION_FOR_TABLE}, *
             FROM system.${table}
         " || continue
     done

docker/test/stateless/run.sh

@@ -19,6 +19,11 @@ dpkg -i package_folder/clickhouse-common-static-dbg_*.deb
 dpkg -i package_folder/clickhouse-server_*.deb
 dpkg -i package_folder/clickhouse-client_*.deb
 
+# Check that the tools are available under short names
+ch --query "SELECT 1" || exit 1
+chl --query "SELECT 1" || exit 1
+chc --version || exit 1
+
 ln -s /usr/share/clickhouse-test/clickhouse-test /usr/bin/clickhouse-test
 
 # shellcheck disable=SC1091
@@ -62,7 +67,7 @@ if [ "$NUM_TRIES" -gt "1" ]; then
     export THREAD_FUZZER_pthread_mutex_unlock_AFTER_SLEEP_TIME_US=10000
 
     mkdir -p /var/run/clickhouse-server
-    # simpliest way to forward env variables to server
+    # simplest way to forward env variables to server
     sudo -E -u clickhouse /usr/bin/clickhouse-server --config /etc/clickhouse-server/config.xml --daemon --pid-file /var/run/clickhouse-server/clickhouse-server.pid
 else
     sudo clickhouse start

docs/en/operations/utilities/clickhouse-keeper-client.md

@@ -12,6 +12,7 @@ A client application to interact with clickhouse-keeper by its native protocol.
 -   `-q QUERY`, `--query=QUERY` — Query to execute. If this parameter is not passed, `clickhouse-keeper-client` will start in interactive mode.
 -   `-h HOST`, `--host=HOST` — Server host. Default value: `localhost`.
 -   `-p N`, `--port=N` — Server port. Default value: 9181
+-   `-c FILE_PATH`, `--config-file=FILE_PATH` — Set path of config file to get the connection string. Default value: `config.xml`.
 -   `--connection-timeout=TIMEOUT` — Set connection timeout in seconds. Default value: 10s.
 -   `--session-timeout=TIMEOUT` — Set session timeout in seconds. Default value: 10s.
 -   `--operation-timeout=TIMEOUT` — Set operation timeout in seconds. Default value: 10s.

docs/en/sql-reference/functions/rounding-functions.md

@@ -107,11 +107,7 @@ round(3.65, 1) = 3.6
 
 Rounds a number to a specified decimal position.
 
-- If the rounding number is halfway between two numbers, the function uses banker’s rounding.
+- If the rounding number is halfway between two numbers, the function uses banker’s rounding. Banker's rounding is a method of rounding fractional numbers. When the rounding number is halfway between two numbers, it's rounded to the nearest even digit at the specified decimal position. For example: 3.5 rounds up to 4, 2.5 rounds down to 2. It's the default rounding method for floating point numbers defined in [IEEE 754](https://en.wikipedia.org/wiki/IEEE_754#Roundings_to_nearest). The [round](#rounding_functions-round) function performs the same rounding for floating point numbers. The `roundBankers` function also rounds integers the same way, for example, `roundBankers(45, -1) = 40`.
-
-        Banker's rounding is a method of rounding fractional numbers. When the rounding number is halfway between two numbers, it's rounded to the nearest even digit at the specified decimal position. For example: 3.5 rounds up to 4, 2.5 rounds down to 2.
-
-        It's the default rounding method for floating point numbers defined in [IEEE 754](https://en.wikipedia.org/wiki/IEEE_754#Roundings_to_nearest). The [round](#rounding_functions-round) function performs the same rounding for floating point numbers. The `roundBankers` function also rounds integers the same way, for example, `roundBankers(45, -1) = 40`.
 
 - In other cases, the function rounds numbers to the nearest integer.
 

docs/en/sql-reference/functions/tuple-functions.md

@@ -171,7 +171,8 @@ Result:
 Can be used with [MinHash](../../sql-reference/functions/hash-functions.md#ngramminhash) functions for detection of semi-duplicate strings:
 
 ``` sql
-SELECT tupleHammingDistance(wordShingleMinHash(string), wordShingleMinHashCaseInsensitive(string)) as HammingDistance FROM (SELECT 'ClickHouse is a column-oriented database management system for online analytical processing of queries.' AS string);
+SELECT tupleHammingDistance(wordShingleMinHash(string), wordShingleMinHashCaseInsensitive(string)) AS HammingDistance
+FROM (SELECT 'ClickHouse is a column-oriented database management system for online analytical processing of queries.' AS string);
 ```
 
 Result:

programs/copier/ClusterCopier.cpp

@@ -5,6 +5,7 @@
 
 #include <Common/ZooKeeper/ZooKeeper.h>
 #include <Common/ZooKeeper/KeeperException.h>
+#include <Common/randomSeed.h>
 #include <Common/setThreadName.h>
 #include <Common/CurrentMetrics.h>
 #include <Interpreters/InterpreterInsertQuery.h>
@@ -59,7 +60,7 @@ void ClusterCopier::init()
     getContext()->setClustersConfig(task_cluster_current_config, false, task_cluster->clusters_prefix);
 
     /// Set up shards and their priority
-    task_cluster->random_engine.seed(task_cluster->random_device());
+    task_cluster->random_engine.seed(randomSeed());
     for (auto & task_table : task_cluster->table_tasks)
     {
         task_table.cluster_pull = getContext()->getCluster(task_table.cluster_pull_name);

programs/copier/TaskCluster.h

@@ -7,7 +7,7 @@
 
 #include <Poco/Util/AbstractConfiguration.h>
 
-#include <random>
+#include <pcg_random.hpp>
 
 namespace DB
 {
@@ -45,7 +45,6 @@ struct TaskCluster
     /// Subtasks
     TasksTable table_tasks;
 
-    std::random_device random_device;
     pcg64 random_engine;
 };
 

programs/install/Install.cpp

@@ -420,7 +420,7 @@ int mainEntryClickHouseInstall(int argc, char ** argv)
 
         /// Create symlinks.
 
-        std::initializer_list<const char *> tools
+        std::initializer_list<std::string_view> tools
         {
             "clickhouse-server",
             "clickhouse-client",
@@ -435,6 +435,9 @@ int mainEntryClickHouseInstall(int argc, char ** argv)
             "clickhouse-keeper",
             "clickhouse-keeper-converter",
             "clickhouse-disks",
+            "ch",
+            "chl",
+            "chc",
         };
 
         for (const auto & tool : tools)
@@ -444,29 +447,39 @@ int mainEntryClickHouseInstall(int argc, char ** argv)
 
             if (fs::exists(symlink_path))
             {
-                bool is_symlink = FS::isSymlink(symlink_path);
+                /// Do not replace short named symlinks if they are already present in the system
-                fs::path points_to;
+                /// to avoid collision with other tools.
-                if (is_symlink)
+                if (!tool.starts_with("clickhouse"))
-                    points_to = fs::weakly_canonical(FS::readSymlink(symlink_path));
-
-                if (is_symlink && (points_to == main_bin_path || (options.count("link") && points_to == binary_self_canonical_path)))
                 {
+                    fmt::print("Symlink {} already exists. Will keep it.\n", symlink_path.string());
                     need_to_create = false;
                 }
                 else
                 {
-                    if (!is_symlink)
+                    bool is_symlink = FS::isSymlink(symlink_path);
+                    fs::path points_to;
+                    if (is_symlink)
+                        points_to = fs::weakly_canonical(FS::readSymlink(symlink_path));
+
+                    if (is_symlink && (points_to == main_bin_path || (options.count("link") && points_to == binary_self_canonical_path)))
                     {
-                        fs::path rename_path = symlink_path.replace_extension(".old");
+                        need_to_create = false;
-                        fmt::print("File {} already exists but it's not a symlink. Will rename to {}.\n",
-                                   symlink_path.string(), rename_path.string());
-                        fs::rename(symlink_path, rename_path);
                     }
-                    else if (points_to != main_bin_path)
+                    else
                     {
-                        fmt::print("Symlink {} already exists but it points to {}. Will replace the old symlink to {}.\n",
+                        if (!is_symlink)
-                                   symlink_path.string(), points_to.string(), main_bin_path.string());
+                        {
-                        fs::remove(symlink_path);
+                            fs::path rename_path = symlink_path.replace_extension(".old");
+                            fmt::print("File {} already exists but it's not a symlink. Will rename to {}.\n",
+                                       symlink_path.string(), rename_path.string());
+                            fs::rename(symlink_path, rename_path);
+                        }
+                        else if (points_to != main_bin_path)
+                        {
+                            fmt::print("Symlink {} already exists but it points to {}. Will replace the old symlink to {}.\n",
+                                       symlink_path.string(), points_to.string(), main_bin_path.string());
+                            fs::remove(symlink_path);
+                        }
                     }
                 }
             }

programs/main.cpp

@@ -2,15 +2,12 @@
 #include <csetjmp>
 #include <unistd.h>
 
-#ifdef OS_LINUX
-#include <sys/mman.h>
-#endif
-
 #include <new>
 #include <iostream>
 #include <vector>
 #include <string>
 #include <tuple>
+#include <string_view>
 #include <utility> /// pair
 
 #include <fmt/format.h>
@@ -22,7 +19,6 @@
 #include <Common/IO.h>
 
 #include <base/phdr_cache.h>
-#include <base/scope_guard.h>
 
 
 /// Universal executable for various clickhouse applications
@@ -98,7 +94,7 @@ using MainFunc = int (*)(int, char**);
 #if !defined(FUZZING_MODE)
 
 /// Add an item here to register new application
-std::pair<const char *, MainFunc> clickhouse_applications[] =
+std::pair<std::string_view, MainFunc> clickhouse_applications[] =
 {
 #if ENABLE_CLICKHOUSE_LOCAL
     {"local", mainEntryClickHouseLocal},
@@ -158,6 +154,18 @@ std::pair<const char *, MainFunc> clickhouse_applications[] =
 #endif
 };
 
+/// Add an item here to register a new short name
+std::pair<std::string_view, std::string_view> clickhouse_short_names[] =
+{
+#if ENABLE_CLICKHOUSE_LOCAL
+    {"ch", "local"},
+    {"chl", "local"},
+#endif
+#if ENABLE_CLICKHOUSE_CLIENT
+    {"chc", "client"},
+#endif
+};
+
 int printHelp(int, char **)
 {
     std::cerr << "Use one of the following commands:" << std::endl;
@@ -387,15 +395,21 @@ void checkHarmfulEnvironmentVariables(char ** argv)
 
 }
 
-bool isClickhouseApp(const std::string & app_suffix, std::vector<char *> & argv)
+bool isClickhouseApp(std::string_view app_suffix, std::vector<char *> & argv)
 {
+    for (const auto & [alias, name] : clickhouse_short_names)
+        if (app_suffix == name
+            && !argv.empty() && (alias == argv[0] || endsWith(argv[0], "/" + std::string(alias))))
+            return true;
+
     /// Use app if the first arg 'app' is passed (the arg should be quietly removed)
     if (argv.size() >= 2)
     {
         auto first_arg = argv.begin() + 1;
 
         /// 'clickhouse --client ...' and 'clickhouse client ...' are Ok
-        if (*first_arg == "--" + app_suffix || *first_arg == app_suffix)
+        if (*first_arg == app_suffix
+            || (std::string_view(*first_arg).starts_with("--") && std::string_view(*first_arg).substr(2) == app_suffix))
         {
             argv.erase(first_arg);
             return true;
@@ -403,7 +417,7 @@ bool isClickhouseApp(const std::string & app_suffix, std::vector<char *> & argv)
     }
 
     /// Use app if clickhouse binary is run through symbolic link with name clickhouse-app
-    std::string app_name = "clickhouse-" + app_suffix;
+    std::string app_name = "clickhouse-" + std::string(app_suffix);
     return !argv.empty() && (app_name == argv[0] || endsWith(argv[0], "/" + app_name));
 }
 

programs/server/users.d/allow_introspection_functions.xml

@@ -1,7 +0,0 @@
-<clickhouse>
-    <profiles>
-        <default>
-            <allow_introspection_functions>1</allow_introspection_functions>
-        </default>
-    </profiles>
-</clickhouse>

programs/server/users.d/allow_introspection_functions.yaml

@@ -0,0 +1 @@
+../../../tests/config/users.d/allow_introspection_functions.yaml

src/Backups/BackupImpl.cpp

@@ -3,6 +3,7 @@
 #include <Backups/BackupFileInfo.h>
 #include <Backups/BackupIO.h>
 #include <Backups/IBackupEntry.h>
+#include <Common/ProfileEvents.h>
 #include <Common/StringUtils/StringUtils.h>
 #include <base/hex.h>
 #include <Common/logger_useful.h>
@@ -24,6 +25,14 @@
 #include <Poco/DOM/DOMParser.h>
 
 
+namespace ProfileEvents
+{
+    extern const Event BackupsOpenedForRead;
+    extern const Event BackupsOpenedForWrite;
+    extern const Event BackupReadMetadataMicroseconds;
+    extern const Event BackupWriteMetadataMicroseconds;
+}
+
 namespace DB
 {
 namespace ErrorCodes
@@ -89,12 +98,14 @@ BackupImpl::BackupImpl(
     , archive_params(archive_params_)
     , open_mode(OpenMode::READ)
     , reader(std::move(reader_))
+    , context(context_)
     , is_internal_backup(false)
     , version(INITIAL_BACKUP_VERSION)
     , base_backup_info(base_backup_info_)
     , use_same_s3_credentials_for_base_backup(use_same_s3_credentials_for_base_backup_)
+    , log(&Poco::Logger::get("BackupImpl"))
 {
-    open(context_);
+    open();
 }
 
 
@@ -115,6 +126,7 @@ BackupImpl::BackupImpl(
     , archive_params(archive_params_)
     , open_mode(OpenMode::WRITE)
     , writer(std::move(writer_))
+    , context(context_)
     , is_internal_backup(is_internal_backup_)
     , coordination(coordination_)
     , uuid(backup_uuid_)
@@ -124,7 +136,7 @@ BackupImpl::BackupImpl(
     , use_same_s3_credentials_for_base_backup(use_same_s3_credentials_for_base_backup_)
     , log(&Poco::Logger::get("BackupImpl"))
 {
-    open(context_);
+    open();
 }
 
 
@@ -140,9 +152,11 @@ BackupImpl::~BackupImpl()
     }
 }
 
-void BackupImpl::open(const ContextPtr & context)
+void BackupImpl::open()
 {
     std::lock_guard lock{mutex};
+    LOG_INFO(log, "{} backup: {}", ((open_mode == OpenMode::WRITE) ? "Writing" : "Reading"), backup_name_for_logging);
+    ProfileEvents::increment((open_mode == OpenMode::WRITE) ? ProfileEvents::BackupsOpenedForWrite : ProfileEvents::BackupsOpenedForRead);
 
     if (open_mode == OpenMode::WRITE)
     {
@@ -166,35 +180,8 @@ void BackupImpl::open(const ContextPtr & context)
     if (open_mode == OpenMode::READ)
         readBackupMetadata();
 
-    if (base_backup_info)
+    if ((open_mode == OpenMode::WRITE) && base_backup_info)
-    {
+        base_backup_uuid = getBaseBackupUnlocked()->getUUID();
-        if (use_same_s3_credentials_for_base_backup)
-            backup_info.copyS3CredentialsTo(*base_backup_info);
-
-        BackupFactory::CreateParams params;
-        params.backup_info = *base_backup_info;
-        params.open_mode = OpenMode::READ;
-        params.context = context;
-        /// use_same_s3_credentials_for_base_backup should be inherited for base backups
-        params.use_same_s3_credentials_for_base_backup = use_same_s3_credentials_for_base_backup;
-
-        base_backup = BackupFactory::instance().createBackup(params);
-
-        if (open_mode == OpenMode::WRITE)
-        {
-            base_backup_uuid = base_backup->getUUID();
-        }
-        else if (base_backup_uuid != base_backup->getUUID())
-        {
-            throw Exception(
-                ErrorCodes::WRONG_BASE_BACKUP,
-                "Backup {}: The base backup {} has different UUID ({} != {})",
-                backup_name_for_logging,
-                base_backup->getNameForLogging(),
-                toString(base_backup->getUUID()),
-                (base_backup_uuid ? toString(*base_backup_uuid) : ""));
-        }
-    }
 }
 
 void BackupImpl::close()
@@ -239,6 +226,42 @@ void BackupImpl::closeArchive()
     archive_writer.reset();
 }
 
+std::shared_ptr<const IBackup> BackupImpl::getBaseBackup() const
+{
+    std::lock_guard lock{mutex};
+    return getBaseBackupUnlocked();
+}
+
+std::shared_ptr<const IBackup> BackupImpl::getBaseBackupUnlocked() const
+{
+    if (!base_backup && base_backup_info)
+    {
+        if (use_same_s3_credentials_for_base_backup)
+            backup_info.copyS3CredentialsTo(*base_backup_info);
+
+        BackupFactory::CreateParams params;
+        params.backup_info = *base_backup_info;
+        params.open_mode = OpenMode::READ;
+        params.context = context;
+        /// use_same_s3_credentials_for_base_backup should be inherited for base backups
+        params.use_same_s3_credentials_for_base_backup = use_same_s3_credentials_for_base_backup;
+
+        base_backup = BackupFactory::instance().createBackup(params);
+
+        if ((open_mode == OpenMode::READ) && (base_backup_uuid != base_backup->getUUID()))
+        {
+            throw Exception(
+                ErrorCodes::WRONG_BASE_BACKUP,
+                "Backup {}: The base backup {} has different UUID ({} != {})",
+                backup_name_for_logging,
+                base_backup->getNameForLogging(),
+                toString(base_backup->getUUID()),
+                (base_backup_uuid ? toString(*base_backup_uuid) : ""));
+        }
+    }
+    return base_backup;
+}
+
 size_t BackupImpl::getNumFiles() const
 {
     std::lock_guard lock{mutex};
@@ -289,8 +312,10 @@ UInt64 BackupImpl::getNumReadBytes() const
 
 void BackupImpl::writeBackupMetadata()
 {
-    assert(!is_internal_backup);
+    LOG_TRACE(log, "Backup {}: Writing metadata", backup_name_for_logging);
+    auto timer = DB::CurrentThread::getProfileEvents().timer(ProfileEvents::BackupWriteMetadataMicroseconds);
 
+    assert(!is_internal_backup);
     checkLockFile(true);
 
     std::unique_ptr<WriteBuffer> out;
@@ -374,11 +399,16 @@ void BackupImpl::writeBackupMetadata()
     out->finalize();
 
     uncompressed_size = size_of_entries + out->count();
+
+    LOG_TRACE(log, "Backup {}: Metadata was written", backup_name_for_logging);
 }
 
 
 void BackupImpl::readBackupMetadata()
 {
+    LOG_TRACE(log, "Backup {}: Reading metadata", backup_name_for_logging);
+    auto timer = DB::CurrentThread::getProfileEvents().timer(ProfileEvents::BackupReadMetadataMicroseconds);
+
     using namespace XMLUtils;
 
     std::unique_ptr<ReadBuffer> in;
@@ -482,6 +512,8 @@ void BackupImpl::readBackupMetadata()
     compressed_size = uncompressed_size;
     if (!use_archive)
         setCompressedSize();
+
+    LOG_TRACE(log, "Backup {}: Metadata was read", backup_name_for_logging);
 }
 
 void BackupImpl::checkBackupDoesntExist() const
@@ -705,7 +737,8 @@ std::unique_ptr<SeekableReadBuffer> BackupImpl::readFileImpl(const SizeAndChecks
     if (info.base_size)
     {
         /// Make `base_read_buffer` if there is data for this backup entry in the base backup.
-        if (!base_backup)
+        auto base = getBaseBackup();
+        if (!base)
         {
             throw Exception(
                 ErrorCodes::NO_BASE_BACKUP,
@@ -713,7 +746,7 @@ std::unique_ptr<SeekableReadBuffer> BackupImpl::readFileImpl(const SizeAndChecks
                 backup_name_for_logging, formatSizeAndChecksum(size_and_checksum));
         }
 
-        if (!base_backup->fileExists(std::pair(info.base_size, info.base_checksum)))
+        if (!base->fileExists(std::pair(info.base_size, info.base_checksum)))
         {
             throw Exception(
                 ErrorCodes::WRONG_BASE_BACKUP,
@@ -721,7 +754,7 @@ std::unique_ptr<SeekableReadBuffer> BackupImpl::readFileImpl(const SizeAndChecks
                 backup_name_for_logging, formatSizeAndChecksum(size_and_checksum));
         }
 
-        base_read_buffer = base_backup->readFile(std::pair{info.base_size, info.base_checksum});
+        base_read_buffer = base->readFile(std::pair{info.base_size, info.base_checksum});
     }
 
     {
@@ -809,7 +842,7 @@ size_t BackupImpl::copyFileToDisk(const SizeAndChecksum & size_and_checksum,
     else if (info.size && (info.size == info.base_size))
     {
         /// Data comes completely from the base backup (nothing comes from this backup).
-        base_backup->copyFileToDisk(std::pair{info.base_size, info.base_checksum}, destination_disk, destination_path, write_mode);
+        getBaseBackup()->copyFileToDisk(std::pair{info.base_size, info.base_checksum}, destination_disk, destination_path, write_mode);
         file_copied = true;
     }
 

src/Backups/BackupImpl.h

@@ -60,7 +60,7 @@ public:
     OpenMode getOpenMode() const override { return open_mode; }
     time_t getTimestamp() const override { return timestamp; }
     UUID getUUID() const override { return *uuid; }
-    BackupPtr getBaseBackup() const override { return base_backup; }
+    BackupPtr getBaseBackup() const override;
     size_t getNumFiles() const override;
     UInt64 getTotalSize() const override;
     size_t getNumEntries() const override;
@@ -85,7 +85,7 @@ public:
     bool supportsWritingInMultipleThreads() const override { return !use_archive; }
 
 private:
-    void open(const ContextPtr & context);
+    void open();
     void close();
 
     void openArchive();
@@ -95,6 +95,9 @@ private:
     void writeBackupMetadata() TSA_REQUIRES(mutex);
     void readBackupMetadata() TSA_REQUIRES(mutex);
 
+    /// Returns the base backup or null if there is no base backup.
+    std::shared_ptr<const IBackup> getBaseBackupUnlocked() const TSA_REQUIRES(mutex);
+
     /// Checks that a new backup doesn't exist yet.
     void checkBackupDoesntExist() const;
 
@@ -118,6 +121,7 @@ private:
     const OpenMode open_mode;
     std::shared_ptr<IBackupWriter> writer;
     std::shared_ptr<IBackupReader> reader;
+    const ContextPtr context;
     const bool is_internal_backup;
     std::shared_ptr<IBackupCoordination> coordination;
 
@@ -138,8 +142,8 @@ private:
     mutable size_t num_read_files = 0;
     mutable UInt64 num_read_bytes = 0;
     int version;
-    std::optional<BackupInfo> base_backup_info;
+    mutable std::optional<BackupInfo> base_backup_info;
-    std::shared_ptr<const IBackup> base_backup;
+    mutable std::shared_ptr<const IBackup> base_backup;
     std::optional<UUID> base_backup_uuid;
     std::shared_ptr<IArchiveReader> archive_reader;
     std::shared_ptr<IArchiveWriter> archive_writer;

src/Backups/IBackup.h

@@ -43,7 +43,7 @@ public:
     /// Returns UUID of the backup.
     virtual UUID getUUID() const = 0;
 
-    /// Returns the base backup (can be null).
+    /// Returns the base backup or null if there is no base backup.
     virtual std::shared_ptr<const IBackup> getBaseBackup() const = 0;
 
     /// Returns the number of files stored in the backup. Compare with getNumEntries().

src/Client/ConnectionParameters.cpp

@@ -30,7 +30,8 @@ ConnectionParameters::ConnectionParameters(const Poco::Util::AbstractConfigurati
     , port(connection_port.value_or(getPortFromConfig(config)))
 {
     bool is_secure = config.getBool("secure", false);
-    security = is_secure ? Protocol::Secure::Enable : Protocol::Secure::Disable;
+    bool is_clickhouse_cloud = connection_host.ends_with(".clickhouse.cloud") || connection_host.ends_with(".clickhouse-staging.com");
+    security = (is_secure || is_clickhouse_cloud) ? Protocol::Secure::Enable : Protocol::Secure::Disable;
 
     default_database = config.getString("database", "");
 

src/Common/ProfileEvents.cpp

@@ -546,6 +546,10 @@ The server successfully detected this situation and will download merged part fr
     M(IOUringCQEsCompleted, "Total number of successfully completed io_uring CQEs") \
     M(IOUringCQEsFailed, "Total number of completed io_uring CQEs with failures") \
     \
+    M(BackupsOpenedForRead, "Number of backups opened for reading") \
+    M(BackupsOpenedForWrite, "Number of backups opened for writing") \
+    M(BackupReadMetadataMicroseconds, "Time spent reading backup metadata from .backup file") \
+    M(BackupWriteMetadataMicroseconds, "Time spent writing backup metadata to .backup file") \
     M(BackupEntriesCollectorMicroseconds, "Time spent making backup entries") \
     M(BackupEntriesCollectorForTablesDataMicroseconds, "Time spent making backup entries for tables data") \
     M(BackupEntriesCollectorRunPostTasksMicroseconds, "Time spent running post tasks after making backup entries") \

src/Common/ZooKeeper/ZooKeeperWithFaultInjection.h

@@ -7,6 +7,7 @@
 #include <Common/logger_useful.h>
 #include <Common/randomSeed.h>
 #include "Coordination/KeeperConstants.h"
+#include <pcg_random.hpp>
 
 namespace DB
 {
@@ -42,7 +43,7 @@ public:
     }
 
 private:
-    std::mt19937_64 rndgen;
+    pcg64_fast rndgen;
     std::bernoulli_distribution distribution;
 };
 

src/Common/mysqlxx/PoolWithFailover.cpp

@@ -2,7 +2,9 @@
 #include <ctime>
 #include <random>
 #include <thread>
+#include <pcg_random.hpp>
 #include <mysqlxx/PoolWithFailover.h>
+#include <Common/randomSeed.h>
 #include <IO/WriteBufferFromString.h>
 #include <IO/Operators.h>
 
@@ -44,10 +46,7 @@ PoolWithFailover::PoolWithFailover(
         /// PoolWithFailover objects are stored in a cache inside PoolFactory.
         /// This cache is reset by ExternalDictionariesLoader after every SYSTEM RELOAD DICTIONAR{Y|IES}
         /// which triggers massive re-constructing of connection pools.
-        /// The state of PRNGs like std::mt19937 is considered to be quite heavy
+        static thread_local pcg64_fast rnd_generator(randomSeed());
-        /// thus here we attempt to optimize its construction.
-        static thread_local std::mt19937 rnd_generator(static_cast<uint_fast32_t>(
-                std::hash<std::thread::id>{}(std::this_thread::get_id()) + std::clock()));
         for (auto & [_, replicas] : replicas_by_priority)
         {
             if (replicas.size() > 1)

src/Common/randomSeed.cpp

@@ -13,10 +13,10 @@
 
 namespace DB
 {
-    namespace ErrorCodes
+namespace ErrorCodes
-    {
+{
-        extern const int CANNOT_CLOCK_GETTIME;
+    extern const int CANNOT_CLOCK_GETTIME;
-    }
+}
 }
 
 

src/Compression/CompressionCodecDeflateQpl.cpp

@@ -6,6 +6,7 @@
 #include <Compression/CompressionFactory.h>
 #include <Compression/CompressionInfo.h>
 #include <Poco/Logger.h>
+#include <Common/randomSeed.h>
 #include <Common/logger_useful.h>
 #include "libaccel_config.h"
 #include <Common/MemorySanitizer.h>
@@ -29,7 +30,7 @@ DeflateQplJobHWPool & DeflateQplJobHWPool::instance()
 
 DeflateQplJobHWPool::DeflateQplJobHWPool()
     : max_hw_jobs(0)
-    , random_engine(std::random_device()())
+    , random_engine(randomSeed())
 {
     Poco::Logger * log = &Poco::Logger::get("DeflateQplJobHWPool");
     const char * qpl_version = qpl_get_library_version();

src/Compression/CompressionCodecDeflateQpl.h

@@ -3,6 +3,7 @@
 #include <Compression/ICompressionCodec.h>
 #include <map>
 #include <random>
+#include <pcg_random.hpp>
 #include <qpl/qpl.h>
 
 namespace Poco
@@ -41,7 +42,7 @@ private:
     std::unique_ptr<std::atomic_bool[]> hw_job_ptr_locks;
 
     bool job_pool_ready;
-    std::mt19937 random_engine;
+    pcg64_fast random_engine;
     std::uniform_int_distribution<int> distribution;
 };
 

src/Coordination/CoordinationSettings.cpp

@@ -36,7 +36,7 @@ void CoordinationSettings::loadFromConfig(const String & config_elem, const Poco
 }
 
 
-const String KeeperConfigurationAndSettings::DEFAULT_FOUR_LETTER_WORD_CMD = "conf,cons,crst,envi,ruok,srst,srvr,stat,wchs,dirs,mntr,isro,rcvr,apiv,csnp,lgif,rqld,rclc,clrs,ftfl";
+const String KeeperConfigurationAndSettings::DEFAULT_FOUR_LETTER_WORD_CMD = "conf,cons,crst,envi,ruok,srst,srvr,stat,wchs,dirs,mntr,isro,rcvr,apiv,csnp,lgif,rqld,rclc,clrs,ftfl,ydld";
 
 KeeperConfigurationAndSettings::KeeperConfigurationAndSettings()
     : server_id(NOT_EXIST)

src/Coordination/FourLetterCommand.cpp

@@ -172,6 +172,9 @@ void FourLetterCommandFactory::registerCommands(KeeperDispatcher & keeper_dispat
         FourLetterCommandPtr feature_flags_command = std::make_shared<FeatureFlagsCommand>(keeper_dispatcher);
         factory.registerCommand(feature_flags_command);
 
+        FourLetterCommandPtr yield_leadership_command = std::make_shared<YieldLeadershipCommand>(keeper_dispatcher);
+        factory.registerCommand(yield_leadership_command);
+
         factory.initializeAllowList(keeper_dispatcher);
         factory.setInitialize(true);
     }
@@ -579,4 +582,10 @@ String FeatureFlagsCommand::run()
     return ret.str();
 }
 
+String YieldLeadershipCommand::run()
+{
+    keeper_dispatcher.yieldLeadership();
+    return "Sent yield leadership request to leader.";
+}
+
 }

src/Coordination/FourLetterCommand.h

@@ -415,4 +415,17 @@ struct FeatureFlagsCommand : public IFourLetterCommand
     ~FeatureFlagsCommand() override = default;
 };
 
+/// Yield leadership and become follower.
+struct YieldLeadershipCommand : public IFourLetterCommand
+{
+    explicit YieldLeadershipCommand(KeeperDispatcher & keeper_dispatcher_)
+        : IFourLetterCommand(keeper_dispatcher_)
+    {
+    }
+
+    String name() override { return "ydld"; }
+    String run() override;
+    ~YieldLeadershipCommand() override = default;
+};
+
 }

src/Coordination/KeeperDispatcher.h

@@ -237,6 +237,12 @@ public:
         return server->requestLeader();
     }
 
+    /// Yield leadership and become follower.
+    void yieldLeadership()
+    {
+        return server->yieldLeadership();
+    }
+
     void recalculateStorageStats()
     {
         return server->recalculateStorageStats();

src/Coordination/KeeperServer.cpp

@@ -1101,6 +1101,12 @@ bool KeeperServer::requestLeader()
     return isLeader() || raft_instance->request_leadership();
 }
 
+void KeeperServer::yieldLeadership()
+{
+    if (isLeader())
+        raft_instance->yield_leadership();
+}
+
 void KeeperServer::recalculateStorageStats()
 {
     state_machine->recalculateStorageStats();

src/Coordination/KeeperServer.h

@@ -144,6 +144,8 @@ public:
 
     bool requestLeader();
 
+    void yieldLeadership();
+
     void recalculateStorageStats();
 };
 

src/Databases/MySQL/MaterializedMySQLSyncThread.cpp

@@ -26,12 +26,14 @@
 #include <Interpreters/executeQuery.h>
 #include <Storages/StorageMergeTree.h>
 #include <Common/quoteString.h>
+#include <Common/randomSeed.h>
 #include <Common/setThreadName.h>
 #include <base/sleep.h>
 #include <boost/algorithm/string/split.hpp>
 #include <boost/algorithm/string/trim.hpp>
 #include <Parsers/CommonParsers.h>
 #include <Parsers/ASTIdentifier.h>
+#include <pcg_random.hpp>
 
 namespace DB
 {
@@ -428,9 +430,8 @@ static inline void dumpDataForTables(
 
 static inline UInt32 randomNumber()
 {
-    std::mt19937 rng;
+    pcg64_fast rng{randomSeed()};
-    rng.seed(std::random_device()());
+    std::uniform_int_distribution<pcg64_fast::result_type> dist6(
-    std::uniform_int_distribution<std::mt19937::result_type> dist6(
         std::numeric_limits<UInt32>::min(), std::numeric_limits<UInt32>::max());
     return static_cast<UInt32>(dist6(rng));
 }

src/Functions/FunctionsConversion.h

@@ -4159,6 +4159,61 @@ arguments, result_type, input_rows_count); \
         };
     }
 
+    template <typename EnumType>
+    WrapperType createEnumToStringWrapper() const
+    {
+        const char * function_name = cast_name;
+        return [function_name] (
+            ColumnsWithTypeAndName & arguments, const DataTypePtr & res_type, const ColumnNullable * nullable_col, size_t /*input_rows_count*/)
+        {
+            using ColumnEnumType = EnumType::ColumnType;
+
+            const auto & first_col = arguments.front().column.get();
+            const auto & first_type = arguments.front().type.get();
+
+            const ColumnEnumType * enum_col = typeid_cast<const ColumnEnumType *>(first_col);
+            const EnumType * enum_type = typeid_cast<const EnumType *>(first_type);
+
+            if (enum_col && nullable_col && nullable_col->size() != enum_col->size())
+                throw Exception(ErrorCodes::LOGICAL_ERROR, "ColumnNullable is not compatible with original");
+
+            if (enum_col && enum_type)
+            {
+                const auto size = enum_col->size();
+                const auto & enum_data = enum_col->getData();
+
+                auto res = res_type->createColumn();
+
+                if (nullable_col)
+                {
+                    for (size_t i = 0; i < size; ++i)
+                    {
+                        if (!nullable_col->isNullAt(i))
+                        {
+                            const auto & value = enum_type->getNameForValue(enum_data[i]);
+                            res->insertData(value.data, value.size);
+                        }
+                        else
+                            res->insertDefault();
+                    }
+                }
+                else
+                {
+                    for (size_t i = 0; i < size; ++i)
+                    {
+                        const auto & value = enum_type->getNameForValue(enum_data[i]);
+                        res->insertData(value.data, value.size);
+                    }
+                }
+
+                return res;
+            }
+            else
+                throw Exception(ErrorCodes::LOGICAL_ERROR, "Unexpected column {} as first argument of function {}",
+                    first_col->getName(), function_name);
+        };
+    }
+
     static WrapperType createIdentityWrapper(const DataTypePtr &)
     {
         return [] (ColumnsWithTypeAndName & arguments, const DataTypePtr &, const ColumnNullable *, size_t /*input_rows_count*/)
@@ -4546,7 +4601,12 @@ arguments, result_type, input_rows_count); \
 
             if constexpr (WhichDataType(ToDataType::type_id).isStringOrFixedString())
             {
-                if (from_type->getCustomSerialization())
+                if constexpr (WhichDataType(FromDataType::type_id).isEnum())
+                {
+                    ret = createEnumToStringWrapper<FromDataType>();
+                    return true;
+                }
+                else if (from_type->getCustomSerialization())
                 {
                     ret = [](ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, const ColumnNullable *, size_t input_rows_count) -> ColumnPtr
                     {

src/Interpreters/Cache/QueryCache.cpp

@@ -147,17 +147,18 @@ QueryCache::Key::Key(ASTPtr ast_, const String & user_name_)
 {
 }
 
+/// Hashing of ASTs must consider aliases (issue #56258)
+constexpr bool ignore_aliases = false;
+
 bool QueryCache::Key::operator==(const Key & other) const
 {
-    return ast->getTreeHash() == other.ast->getTreeHash();
+    return ast->getTreeHash(ignore_aliases) == other.ast->getTreeHash(ignore_aliases);
 }
 
 size_t QueryCache::KeyHasher::operator()(const Key & key) const
 {
-    SipHash hash;
+    IAST::Hash hash = key.ast->getTreeHash(ignore_aliases);
-    hash.update(key.ast->getTreeHash());
+    return hash.low64;
-    auto res = hash.get64();
-    return res;
 }
 
 size_t QueryCache::QueryCacheEntryWeight::operator()(const Entry & entry) const

src/Interpreters/Cluster.cpp

@@ -4,6 +4,7 @@
 #include <Common/isLocalAddress.h>
 #include <Common/StringUtils/StringUtils.h>
 #include <Common/parseAddress.h>
+#include <Common/randomSeed.h>
 #include <Common/Config/AbstractConfigurationComparison.h>
 #include <Common/Config/ConfigHelper.h>
 #include <Core/Settings.h>
@@ -16,6 +17,7 @@
 #include <boost/range/algorithm_ext/erase.hpp>
 
 #include <span>
+#include <pcg_random.hpp>
 
 namespace DB
 {
@@ -660,8 +662,7 @@ namespace
 
 void shuffleReplicas(std::vector<Cluster::Address> & replicas, const Settings & settings, size_t replicas_needed)
 {
-    std::random_device rd;
+    pcg64_fast gen{randomSeed()};
-    std::mt19937 gen{rd()};
 
     if (settings.prefer_localhost_replica)
     {

src/Interpreters/examples/string_hash_map.cpp

@@ -14,24 +14,25 @@
 
 /**
 
+#include <Common/randomSeed.h>
 #include <fstream>
 #include <random>
+#include <pcg_random.hpp>
 
 using namespace std;
 
 int main()
 {
     std::string s;
-    std::random_device dev;
+    pcg64_fast rng{randomSeed()};
-    std::mt19937 rng(dev());
+    std::uniform_int_distribution<pcg64_fast::result_type> dist(0, 25);
-    std::uniform_int_distribution<std::mt19937::result_type> dist(0, 25);
+    std::binomial_distribution<pcg64_fast::result_type> binomial1(100, 0.01);
-    std::binomial_distribution<std::mt19937::result_type> binomial1(100, 0.01);
+    std::binomial_distribution<pcg64_fast::result_type> binomial2(100, 0.02);
-    std::binomial_distribution<std::mt19937::result_type> binomial2(100, 0.02);
+    std::binomial_distribution<pcg64_fast::result_type> binomial4(100, 0.04);
-    std::binomial_distribution<std::mt19937::result_type> binomial4(100, 0.04);
+    std::binomial_distribution<pcg64_fast::result_type> binomial8(100, 0.08);
-    std::binomial_distribution<std::mt19937::result_type> binomial8(100, 0.08);
+    std::binomial_distribution<pcg64_fast::result_type> binomial16(100, 0.16);
-    std::binomial_distribution<std::mt19937::result_type> binomial16(100, 0.16);
+    std::binomial_distribution<pcg64_fast::result_type> binomial24(100, 0.24);
-    std::binomial_distribution<std::mt19937::result_type> binomial24(100, 0.24);
+    std::binomial_distribution<pcg64_fast::result_type> binomial48(100, 0.48);
-    std::binomial_distribution<std::mt19937::result_type> binomial48(100, 0.48);
     // 11GB
     std::ofstream f("/tmp/terms.csv");
     size_t l1, l2, l4, l8, l16, l24, l48;

src/Parsers/ASTColumnsMatcher.cpp

@@ -46,11 +46,11 @@ void ASTColumnsRegexpMatcher::appendColumnName(WriteBuffer & ostr) const
     writeChar(')', ostr);
 }
 
-void ASTColumnsRegexpMatcher::updateTreeHashImpl(SipHash & hash_state) const
+void ASTColumnsRegexpMatcher::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(original_pattern.size());
     hash_state.update(original_pattern);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTColumnsRegexpMatcher::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
@@ -201,11 +201,11 @@ const std::shared_ptr<re2::RE2> & ASTQualifiedColumnsRegexpMatcher::getMatcher()
     return column_matcher;
 }
 
-void ASTQualifiedColumnsRegexpMatcher::updateTreeHashImpl(SipHash & hash_state) const
+void ASTQualifiedColumnsRegexpMatcher::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(original_pattern.size());
     hash_state.update(original_pattern);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTQualifiedColumnsRegexpMatcher::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const

src/Parsers/ASTColumnsMatcher.h

@@ -27,7 +27,7 @@ public:
     const String & getPattern() const;
     const std::shared_ptr<re2::RE2> & getMatcher() const;
     bool isColumnMatching(const String & column_name) const;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     ASTPtr expression;
     ASTPtr transformers;
@@ -65,7 +65,7 @@ public:
     const std::shared_ptr<re2::RE2> & getMatcher() const;
     void setPattern(String pattern, bool set_matcher = true);
     void setMatcher(std::shared_ptr<re2::RE2> matcher);
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     ASTPtr qualifier;
     ASTPtr transformers;

src/Parsers/ASTColumnsTransformers.cpp

@@ -151,15 +151,15 @@ void ASTColumnsApplyTransformer::appendColumnName(WriteBuffer & ostr) const
     }
 }
 
-void ASTColumnsApplyTransformer::updateTreeHashImpl(SipHash & hash_state) const
+void ASTColumnsApplyTransformer::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(func_name.size());
     hash_state.update(func_name);
     if (parameters)
-        parameters->updateTreeHashImpl(hash_state);
+        parameters->updateTreeHashImpl(hash_state, ignore_aliases);
 
     if (lambda)
-        lambda->updateTreeHashImpl(hash_state);
+        lambda->updateTreeHashImpl(hash_state, ignore_aliases);
 
     hash_state.update(lambda_arg.size());
     hash_state.update(lambda_arg);
@@ -167,7 +167,7 @@ void ASTColumnsApplyTransformer::updateTreeHashImpl(SipHash & hash_state) const
     hash_state.update(column_name_prefix.size());
     hash_state.update(column_name_prefix);
 
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTColumnsExceptTransformer::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
@@ -216,13 +216,13 @@ void ASTColumnsExceptTransformer::appendColumnName(WriteBuffer & ostr) const
         writeChar(')', ostr);
 }
 
-void ASTColumnsExceptTransformer::updateTreeHashImpl(SipHash & hash_state) const
+void ASTColumnsExceptTransformer::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(is_strict);
     hash_state.update(original_pattern.size());
     hash_state.update(original_pattern);
 
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTColumnsExceptTransformer::transform(ASTs & nodes) const
@@ -312,14 +312,14 @@ void ASTColumnsReplaceTransformer::Replacement::appendColumnName(WriteBuffer & o
     writeProbablyBackQuotedString(name, ostr);
 }
 
-void ASTColumnsReplaceTransformer::Replacement::updateTreeHashImpl(SipHash & hash_state) const
+void ASTColumnsReplaceTransformer::Replacement::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     assert(children.size() == 1);
 
     hash_state.update(name.size());
     hash_state.update(name);
-    children[0]->updateTreeHashImpl(hash_state);
+    children[0]->updateTreeHashImpl(hash_state, ignore_aliases);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTColumnsReplaceTransformer::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
@@ -361,10 +361,10 @@ void ASTColumnsReplaceTransformer::appendColumnName(WriteBuffer & ostr) const
         writeChar(')', ostr);
 }
 
-void ASTColumnsReplaceTransformer::updateTreeHashImpl(SipHash & hash_state) const
+void ASTColumnsReplaceTransformer::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(is_strict);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTColumnsReplaceTransformer::replaceChildren(ASTPtr & node, const ASTPtr & replacement, const String & name)

src/Parsers/ASTColumnsTransformers.h

@@ -48,7 +48,7 @@ public:
     }
     void transform(ASTs & nodes) const override;
     void appendColumnName(WriteBuffer & ostr) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     // Case 1  APPLY (quantile(0.9))
     String func_name;
@@ -80,7 +80,7 @@ public:
     const std::shared_ptr<re2::RE2> & getMatcher() const;
     bool isColumnMatching(const String & column_name) const;
     void appendColumnName(WriteBuffer & ostr) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
 protected:
     void formatImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
@@ -103,7 +103,7 @@ public:
         }
 
         void appendColumnName(WriteBuffer & ostr) const override;
-        void updateTreeHashImpl(SipHash & hash_state) const override;
+        void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
         String name;
 
@@ -121,7 +121,7 @@ public:
     }
     void transform(ASTs & nodes) const override;
     void appendColumnName(WriteBuffer & ostr) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
 protected:
     void formatImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;

src/Parsers/ASTFunction.cpp

@@ -599,11 +599,11 @@ ASTPtr ASTFunction::clone() const
 }
 
 
-void ASTFunction::updateTreeHashImpl(SipHash & hash_state) const
+void ASTFunction::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(name.size());
     hash_state.update(name);
-    IAST::updateTreeHashImpl(hash_state);
+    ASTWithAlias::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 template <typename Container>

src/Parsers/ASTFunction.h

@@ -63,7 +63,7 @@ public:
 
     ASTPtr clone() const override;
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     ASTSelectWithUnionQuery * tryGetQueryArgument() const;
 

src/Parsers/ASTFunctionWithKeyValueArguments.cpp

@@ -53,12 +53,12 @@ bool ASTPair::hasSecretParts() const
 }
 
 
-void ASTPair::updateTreeHashImpl(SipHash & hash_state) const
+void ASTPair::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(first.size());
     hash_state.update(first);
     hash_state.update(second_with_brackets);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 
@@ -92,12 +92,12 @@ void ASTFunctionWithKeyValueArguments::formatImpl(const FormatSettings & setting
 }
 
 
-void ASTFunctionWithKeyValueArguments::updateTreeHashImpl(SipHash & hash_state) const
+void ASTFunctionWithKeyValueArguments::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(name.size());
     hash_state.update(name);
     hash_state.update(has_brackets);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 }

src/Parsers/ASTFunctionWithKeyValueArguments.h

@@ -32,7 +32,7 @@ public:
 
     bool hasSecretParts() const override;
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     void forEachPointerToChild(std::function<void(void**)> f) override
     {
@@ -66,7 +66,7 @@ public:
 
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 };
 
 }

src/Parsers/ASTIdentifier.cpp

@@ -87,6 +87,11 @@ void ASTIdentifier::setShortName(const String & new_name)
     semantic->table = table;
 }
 
+void ASTIdentifier::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
+{
+    ASTWithAlias::updateTreeHashImpl(hash_state, ignore_aliases);
+}
+
 const String & ASTIdentifier::name() const
 {
     if (children.empty())
@@ -244,10 +249,10 @@ void ASTTableIdentifier::resetTable(const String & database_name, const String &
     uuid = identifier->uuid;
 }
 
-void ASTTableIdentifier::updateTreeHashImpl(SipHash & hash_state) const
+void ASTTableIdentifier::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(uuid);
-    IAST::updateTreeHashImpl(hash_state);
+    ASTIdentifier::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 String getIdentifierName(const IAST * ast)

src/Parsers/ASTIdentifier.h

@@ -47,6 +47,8 @@ public:
     const String & shortName() const { return name_parts.back(); }
     const String & name() const;
 
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_alias) const override;
+
     void restoreTable();  // TODO(ilezhankin): get rid of this
     std::shared_ptr<ASTTableIdentifier> createTable() const;  // returns |nullptr| if identifier is not table.
 
@@ -91,7 +93,7 @@ public:
     // FIXME: used only when it's needed to rewrite distributed table name to real remote table name.
     void resetTable(const String & database_name, const String & table_name);  // TODO(ilezhankin): get rid of this
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 };
 
 }

src/Parsers/ASTInsertQuery.cpp

@@ -138,13 +138,13 @@ void ASTInsertQuery::formatImpl(const FormatSettings & settings, FormatState & s
     }
 }
 
-void ASTInsertQuery::updateTreeHashImpl(SipHash & hash_state) const
+void ASTInsertQuery::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(table_id.database_name);
     hash_state.update(table_id.table_name);
     hash_state.update(table_id.uuid);
     hash_state.update(format);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 

src/Parsers/ASTInsertQuery.h

@@ -72,7 +72,7 @@ public:
 
 protected:
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 };
 
 }

src/Parsers/ASTLiteral.cpp

@@ -10,11 +10,13 @@
 namespace DB
 {
 
-void ASTLiteral::updateTreeHashImpl(SipHash & hash_state) const
+void ASTLiteral::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     const char * prefix = "Literal_";
     hash_state.update(prefix, strlen(prefix));
     applyVisitor(FieldVisitorHash(hash_state), value);
+    if (!ignore_aliases)
+        ASTWithAlias::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 ASTPtr ASTLiteral::clone() const

src/Parsers/ASTLiteral.h

@@ -41,7 +41,7 @@ public:
 
     ASTPtr clone() const override;
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
 protected:
     void formatImplWithoutAlias(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;

src/Parsers/ASTOrderByElement.cpp

@@ -7,13 +7,13 @@
 namespace DB
 {
 
-void ASTOrderByElement::updateTreeHashImpl(SipHash & hash_state) const
+void ASTOrderByElement::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(direction);
     hash_state.update(nulls_direction);
     hash_state.update(nulls_direction_was_explicitly_specified);
     hash_state.update(with_fill);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 void ASTOrderByElement::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const

src/Parsers/ASTOrderByElement.h

@@ -32,7 +32,7 @@ public:
         return clone;
     }
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
 protected:
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;

src/Parsers/ASTQueryParameter.cpp

@@ -23,4 +23,9 @@ void ASTQueryParameter::appendColumnNameImpl(WriteBuffer & ostr) const
     writeString(name, ostr);
 }
 
+void ASTQueryParameter::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
+{
+    ASTWithAlias::updateTreeHashImpl(hash_state, ignore_aliases);
+}
+
 }

src/Parsers/ASTQueryParameter.h

@@ -21,6 +21,8 @@ public:
 
     ASTPtr clone() const override { return std::make_shared<ASTQueryParameter>(*this); }
 
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
+
 protected:
     void formatImplWithoutAlias(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
     void appendColumnNameImpl(WriteBuffer & ostr) const override;

src/Parsers/ASTSelectQuery.cpp

@@ -42,14 +42,14 @@ ASTPtr ASTSelectQuery::clone() const
 }
 
 
-void ASTSelectQuery::updateTreeHashImpl(SipHash & hash_state) const
+void ASTSelectQuery::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(distinct);
     hash_state.update(group_by_with_totals);
     hash_state.update(group_by_with_rollup);
     hash_state.update(group_by_with_cube);
     hash_state.update(limit_with_ties);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 

src/Parsers/ASTSelectQuery.h

@@ -137,7 +137,7 @@ public:
     void replaceDatabaseAndTable(const String & database_name, const String & table_name);
     void replaceDatabaseAndTable(const StorageID & table_id);
     void addTableFunction(ASTPtr & table_function_ptr);
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     void setFinal();
 

src/Parsers/ASTSetQuery.cpp

@@ -9,7 +9,7 @@
 namespace DB
 {
 
-void ASTSetQuery::updateTreeHashImpl(SipHash & hash_state) const
+void ASTSetQuery::updateTreeHashImpl(SipHash & hash_state, bool /*ignore_aliases*/) const
 {
     for (const auto & change : changes)
     {

src/Parsers/ASTSetQuery.h

@@ -34,7 +34,7 @@ public:
 
     void formatImpl(const FormatSettings & format, FormatState &, FormatStateStacked) const override;
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     QueryKind getQueryKind() const override { return QueryKind::Set; }
 

src/Parsers/ASTSubquery.cpp

@@ -51,11 +51,11 @@ void ASTSubquery::formatImplWithoutAlias(const FormatSettings & settings, Format
     settings.ostr << nl_or_nothing << indent_str << ")";
 }
 
-void ASTSubquery::updateTreeHashImpl(SipHash & hash_state) const
+void ASTSubquery::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     if (!cte_name.empty())
         hash_state.update(cte_name);
-    IAST::updateTreeHashImpl(hash_state);
+    ASTWithAlias::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 String ASTSubquery::getAliasOrColumnName() const

src/Parsers/ASTSubquery.h

@@ -14,7 +14,7 @@ class ASTSubquery : public ASTWithAlias
 public:
     // Stored the name when the subquery is defined in WITH clause. For example:
     // WITH (SELECT 1) AS a SELECT * FROM a AS b; cte_name will be `a`.
-    std::string cte_name;
+    String cte_name;
 
     /** Get the text that identifies this element. */
     String getID(char) const override { return "Subquery"; }
@@ -26,7 +26,7 @@ public:
         return clone;
     }
 
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
     String getAliasOrColumnName() const override;
     String tryGetAlias() const override;
 

src/Parsers/ASTTablesInSelectQuery.cpp

@@ -21,10 +21,10 @@ do \
 while (false)
 
 
-void ASTTableExpression::updateTreeHashImpl(SipHash & hash_state) const
+void ASTTableExpression::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(final);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 
@@ -42,12 +42,12 @@ ASTPtr ASTTableExpression::clone() const
     return res;
 }
 
-void ASTTableJoin::updateTreeHashImpl(SipHash & hash_state) const
+void ASTTableJoin::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(locality);
     hash_state.update(strictness);
     hash_state.update(kind);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 ASTPtr ASTTableJoin::clone() const
@@ -61,10 +61,10 @@ ASTPtr ASTTableJoin::clone() const
     return res;
 }
 
-void ASTArrayJoin::updateTreeHashImpl(SipHash & hash_state) const
+void ASTArrayJoin::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
 {
     hash_state.update(kind);
-    IAST::updateTreeHashImpl(hash_state);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
 }
 
 ASTPtr ASTArrayJoin::clone() const

src/Parsers/ASTTablesInSelectQuery.h

@@ -59,7 +59,7 @@ struct ASTTableExpression : public IAST
     String getID(char) const override { return "TableExpression"; }
     ASTPtr clone() const override;
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 };
 
 
@@ -81,7 +81,7 @@ struct ASTTableJoin : public IAST
     void formatImplBeforeTable(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const;
     void formatImplAfterTable(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const;
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 };
 
 /// Specification of ARRAY JOIN.
@@ -102,7 +102,7 @@ struct ASTArrayJoin : public IAST
     String getID(char) const override { return "ArrayJoin"; }
     ASTPtr clone() const override;
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 };
 
 

src/Parsers/ASTTransactionControl.cpp

@@ -39,7 +39,7 @@ IAST::QueryKind ASTTransactionControl::getQueryKind() const
     }
 }
 
-void ASTTransactionControl::updateTreeHashImpl(SipHash & hash_state) const
+void ASTTransactionControl::updateTreeHashImpl(SipHash & hash_state, bool /*ignore_aliases*/) const
 {
     hash_state.update(action);
 }

src/Parsers/ASTTransactionControl.h

@@ -20,13 +20,13 @@ public:
 
     UInt64 snapshot;    /// For SET TRANSACTION SNAPSHOT ...
 
-    ASTTransactionControl(QueryType action_) : action(action_) {}
+    explicit ASTTransactionControl(QueryType action_) : action(action_) {}
 
     String getID(char /*delimiter*/) const override { return "ASTTransactionControl"; }
     ASTPtr clone() const override { return std::make_shared<ASTTransactionControl>(*this); }
 
     void formatImpl(const FormatSettings & format, FormatState & /*state*/, FormatStateStacked /*frame*/) const override;
-    void updateTreeHashImpl(SipHash & hash_state) const override;
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     QueryKind getQueryKind() const override;
 };

src/Parsers/ASTWithAlias.cpp

@@ -1,3 +1,4 @@
+#include <Common/SipHash.h>
 #include <Parsers/ASTWithAlias.h>
 #include <IO/WriteHelpers.h>
 #include <IO/Operators.h>
@@ -42,6 +43,13 @@ void ASTWithAlias::formatImpl(const FormatSettings & settings, FormatState & sta
     }
 }
 
+void ASTWithAlias::updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const
+{
+    if (!alias.empty() && !ignore_aliases)
+        hash_state.update(alias);
+    IAST::updateTreeHashImpl(hash_state, ignore_aliases);
+}
+
 void ASTWithAlias::appendColumnName(WriteBuffer & ostr) const
 {
     if (prefer_alias_to_column_name && !alias.empty())

src/Parsers/ASTWithAlias.h

@@ -27,7 +27,9 @@ public:
     void setAlias(const String & to) override { alias = to; }
 
     /// Calls formatImplWithoutAlias, and also outputs an alias. If necessary, encloses the entire expression in brackets.
-    void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override final;
+    void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const final;
+
+    void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const override;
 
     virtual void formatImplWithoutAlias(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const = 0;
 

src/Parsers/IAST.cpp

@@ -114,24 +114,24 @@ size_t IAST::checkSize(size_t max_size) const
 }
 
 
-IAST::Hash IAST::getTreeHash() const
+IAST::Hash IAST::getTreeHash(bool ignore_aliases) const
 {
     SipHash hash_state;
-    updateTreeHash(hash_state);
+    updateTreeHash(hash_state, ignore_aliases);
     return getSipHash128AsPair(hash_state);
 }
 
 
-void IAST::updateTreeHash(SipHash & hash_state) const
+void IAST::updateTreeHash(SipHash & hash_state, bool ignore_aliases) const
 {
-    updateTreeHashImpl(hash_state);
+    updateTreeHashImpl(hash_state, ignore_aliases);
     hash_state.update(children.size());
     for (const auto & child : children)
-        child->updateTreeHash(hash_state);
+        child->updateTreeHash(hash_state, ignore_aliases);
 }
 
 
-void IAST::updateTreeHashImpl(SipHash & hash_state) const
+void IAST::updateTreeHashImpl(SipHash & hash_state, bool /*ignore_aliases*/) const
 {
     auto id = getID();
     hash_state.update(id.data(), id.size());

src/Parsers/IAST.h

@@ -78,11 +78,13 @@ public:
     virtual ASTPtr clone() const = 0;
 
     /** Get hash code, identifying this element and its subtree.
+     *  Hashing by default ignores aliases (e.g. identifier aliases, function aliases, literal aliases) which is
+     *  useful for common subexpression elimination. Set 'ignore_aliases = false' if you don't want that behavior.
       */
     using Hash = CityHash_v1_0_2::uint128;
-    Hash getTreeHash() const;
+    Hash getTreeHash(bool ignore_aliases = true) const;
-    void updateTreeHash(SipHash & hash_state) const;
+    void updateTreeHash(SipHash & hash_state, bool ignore_aliases = true) const;
-    virtual void updateTreeHashImpl(SipHash & hash_state) const;
+    virtual void updateTreeHashImpl(SipHash & hash_state, bool ignore_aliases) const;
 
     void dumpTree(WriteBuffer & ostr, size_t indent = 0) const;
     std::string dumpTree(size_t indent = 0) const;

src/Server/PostgreSQLHandler.cpp

@@ -7,9 +7,10 @@
 #include "PostgreSQLHandler.h"
 #include <Parsers/parseQuery.h>
 #include <Server/TCPServer.h>
+#include <Common/randomSeed.h>
 #include <Common/setThreadName.h>
 #include <base/scope_guard.h>
-#include <random>
+#include <pcg_random.hpp>
 
 #include "config_version.h"
 
@@ -284,8 +285,7 @@ void PostgreSQLHandler::processQuery()
         if (!parse_res.second)
             throw Exception(ErrorCodes::SYNTAX_ERROR, "Cannot parse and execute the following part of query: {}", String(parse_res.first));
 
-        std::random_device rd;
+        pcg64_fast gen{randomSeed()};
-        std::mt19937 gen(rd());
         std::uniform_int_distribution<Int32> dis(0, INT32_MAX);
 
         for (const auto & spl_query : queries)

tests/config/install.sh

@@ -82,6 +82,7 @@ ln -sf $SRC_PATH/users.d/marks.xml $DEST_SERVER_PATH/users.d/
 ln -sf $SRC_PATH/users.d/insert_keeper_retries.xml $DEST_SERVER_PATH/users.d/
 ln -sf $SRC_PATH/users.d/prefetch_settings.xml $DEST_SERVER_PATH/users.d/
 ln -sf $SRC_PATH/users.d/nonconst_timezone.xml $DEST_SERVER_PATH/users.d/
+ln -sf $SRC_PATH/users.d/allow_introspection_functions.yaml $DEST_SERVER_PATH/users.d/
 
 if [[ -n "$USE_NEW_ANALYZER" ]] && [[ "$USE_NEW_ANALYZER" -eq 1 ]]; then
     ln -sf $SRC_PATH/users.d/analyzer.xml $DEST_SERVER_PATH/users.d/

tests/config/users.d/allow_introspection_functions.yaml

@@ -0,0 +1,3 @@
+profiles:
+    default:
+        allow_introspection_functions: 1

tests/integration/helpers/keeper_utils.py

@@ -248,6 +248,11 @@ def is_leader(cluster, node, port=9181):
     return "Mode: leader" in stat
 
 
+def is_follower(cluster, node, port=9181):
+    stat = send_4lw_cmd(cluster, node, "stat", port)
+    return "Mode: follower" in stat
+
+
 def get_leader(cluster, nodes):
     for node in nodes:
         if is_leader(cluster, node):

tests/integration/test_keeper_four_word_command/test.py

@@ -725,3 +725,30 @@ def test_cmd_clrs(started_cluster):
 
     finally:
         destroy_zk_client(zk)
+
+
+def test_cmd_ydld(started_cluster):
+    wait_nodes()
+    for node in [node1, node3]:
+        data = keeper_utils.send_4lw_cmd(cluster, node, cmd="ydld")
+        assert data == "Sent yield leadership request to leader."
+
+        print("ydld output -------------------------------------")
+        print(data)
+
+        # Whenever there is a leader switch, there is a brief amount of time when any
+        # of the 4 letter commands will return empty result. Thus, we need to test for
+        # negative condition. So we can't use keeper_utils.is_leader() here and likewise
+        # in the while loop below.
+        if not keeper_utils.is_follower(cluster, node):
+            # wait for it to yield leadership
+            retry = 0
+            while not keeper_utils.is_follower(cluster, node) and retry < 30:
+                time.sleep(1)
+                retry += 1
+            if retry == 30:
+                print(
+                    node.name
+                    + " did not become follower after 30s of yielding leadership, maybe there is something wrong."
+                )
+        assert keeper_utils.is_follower(cluster, node)

tests/queries/0_stateless/01555_system_distribution_queue_mask.sql

@@ -18,7 +18,7 @@ system stop distributed sends dist_01555;
 insert into dist_01555 values (1)(2);
 -- since test_cluster_with_incorrect_pw contains incorrect password ignore error
 system flush distributed dist_01555; -- { serverError 516 }
-select length(splitByChar('*', data_path)), replaceRegexpOne(data_path, '^.*/([^/]*)/' , '\\1'), extract(last_exception, 'AUTHENTICATION_FAILED'), dateDiff('s', last_exception_time, now()) < 5 from system.distribution_queue where database = currentDatabase() and table = 'dist_01555' format CSV;
+select length(splitByChar('*', data_path)), replaceRegexpOne(data_path, '^.*/([^/]*)/' , '\\1'), extract(last_exception, 'AUTHENTICATION_FAILED'), dateDiff('s', last_exception_time, now()) < 3600 from system.distribution_queue where database = currentDatabase() and table = 'dist_01555' format CSV;
 
 drop table dist_01555;
 
@@ -31,7 +31,7 @@ create table dist_01555 (key Int) Engine=Distributed(test_cluster_with_incorrect
 insert into dist_01555 values (1)(2);
 -- since test_cluster_with_incorrect_pw contains incorrect password ignore error
 system flush distributed dist_01555; -- { serverError 516 }
-select length(splitByChar('*', data_path)), replaceRegexpOne(data_path, '^.*/([^/]*)/' , '\\1'), extract(last_exception, 'AUTHENTICATION_FAILED'), dateDiff('s', last_exception_time, now()) < 5 from system.distribution_queue where database = currentDatabase() and table = 'dist_01555' format CSV;
+select length(splitByChar('*', data_path)), replaceRegexpOne(data_path, '^.*/([^/]*)/' , '\\1'), extract(last_exception, 'AUTHENTICATION_FAILED'), dateDiff('s', last_exception_time, now()) < 3600 from system.distribution_queue where database = currentDatabase() and table = 'dist_01555' format CSV;
 
 drop table dist_01555;
 

tests/queries/0_stateless/02494_query_cache_bugs.reference

@@ -0,0 +1,24 @@
+-- Bug 56258: Check literals (ASTLiteral)
+Row 1:
+──────
+10: 10
+Row 1:
+──────
+x: 10
+2
+-- Bug 56258: Check functions (ASTFunction)
+Row 1:
+──────
+toUInt64(42): 42
+Row 1:
+──────
+x: 42
+2
+-- Bug 56258: Check identifiers (ASTIdentifier)
+Row 1:
+──────
+c: 1
+Row 1:
+──────
+x: 1
+2

tests/queries/0_stateless/02494_query_cache_bugs.sql

@@ -0,0 +1,39 @@
+-- Tags: no-parallel
+-- Tag no-parallel: Messes with internal cache
+
+-- Test for Bug 56258
+
+SYSTEM DROP QUERY CACHE;
+
+SELECT '-- Bug 56258: Check literals (ASTLiteral)';
+
+SELECT 10 FORMAT Vertical SETTINGS use_query_cache = 1;
+SELECT 10 AS x FORMAT Vertical SETTINGS use_query_cache = 1;
+
+SELECT count(*) FROM system.query_cache;
+
+SYSTEM DROP QUERY CACHE;
+
+SELECT '-- Bug 56258: Check functions (ASTFunction)';
+
+SELECT toUInt64(42) FORMAT Vertical SETTINGS use_query_cache = 1;
+SELECT toUInt64(42) AS x FORMAT Vertical SETTINGS use_query_cache = 1;
+
+SELECT count(*) FROM system.query_cache;
+
+SYSTEM DROP QUERY CACHE;
+
+SELECT '-- Bug 56258: Check identifiers (ASTIdentifier)';
+
+DROP TABLE IF EXISTS tab;
+
+CREATE TABLE tab(c UInt64) ENGINE = Memory AS SELECT 1;
+
+SELECT c FROM tab FORMAT Vertical SETTINGS use_query_cache = 1;
+SELECT c AS x FROM tab FORMAT Vertical SETTINGS use_query_cache = 1;
+
+SELECT count(*) FROM system.query_cache;
+
+DROP TABLE tab;
+
+SYSTEM DROP QUERY CACHE;

tests/queries/0_stateless/02725_keeper_fault_inject_sequential_cleanup.sql

@@ -1,10 +0,0 @@
-DROP TABLE IF EXISTS keeper_fault_inject_sequential_cleanup;
-
-CREATE TABLE keeper_fault_inject_sequential_cleanup (d Int8) ENGINE = ReplicatedMergeTree('/clickhouse/{database}/test_02725/tables/keeper_fault_inject_sequential_cleanup', '1') ORDER BY d;
-
-INSERT INTO keeper_fault_inject_sequential_cleanup VALUES (1);
-INSERT INTO keeper_fault_inject_sequential_cleanup SETTINGS insert_deduplicate = 0 VALUES (1);
-INSERT INTO keeper_fault_inject_sequential_cleanup SETTINGS insert_deduplicate = 0, insert_keeper_fault_injection_probability = 0.4, insert_keeper_fault_injection_seed = 5619964844601345291 VALUES (1);
-
--- with database ordinary it produced a warning
-DROP TABLE keeper_fault_inject_sequential_cleanup;

tests/queries/0_stateless/02843_backup_use_same_s3_credentials_for_base_backup.reference

@@ -1,14 +1,27 @@
 use_same_s3_credentials_for_base_backup for S3
+base
 BACKUP_CREATED
+inc_1
 BACKUP_CREATED
+inc_2
+BACKUP_CREATED
+inc_3_bad
 The request signature we calculated does not match the signature you provided. Check your key and signing method. (S3_ERROR)
+inc_4
 BACKUP_CREATED
+restore inc_1
 The request signature we calculated does not match the signature you provided. Check your key and signing method. (S3_ERROR)
+restore inc_1
 RESTORED
+restore inc_2
 RESTORED
 use_same_s3_credentials_for_base_backup for S3 (invalid arguments)
+inc_5_bad
 BACKUP_CREATED
+inc_6_bad
 NUMBER_OF_ARGUMENTS_DOESNT_MATCH
 use_same_s3_credentials_for_base_backup for Disk
+backup_1
 BACKUP_CREATED
+backup_2
 BAD_ARGUMENTS

tests/queries/0_stateless/02843_backup_use_same_s3_credentials_for_base_backup.sh

@@ -22,24 +22,41 @@ function write_invalid_password_to_base_backup()
 
 # Returns the arguments for the BACKUP TO S3() function, i.e. (url, access_key_id, secret_access_key)
 function s3_location() { echo "'http://localhost:11111/test/backups/$CLICKHOUSE_DATABASE/use_same_s3_credentials_for_base_backup_base_$*', 'test', 'testtest'"; }
+function s3_location_with_invalid_password() { echo "'http://localhost:11111/test/backups/$CLICKHOUSE_DATABASE/use_same_s3_credentials_for_base_backup_base_$*', 'test', 'INVALID_PASSWORD'"; }
 
 echo 'use_same_s3_credentials_for_base_backup for S3'
+echo "base"
 $CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location base))" | cut -f2
+
+echo "inc_1"
 $CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_1)) SETTINGS base_backup=S3($(s3_location base))" | cut -f2
 write_invalid_password_to_base_backup inc_1
-$CLICKHOUSE_CLIENT --format Null -q "BACKUP TABLE data TO S3($(s3_location inc_2)) SETTINGS base_backup=S3($(s3_location inc_1))" |& grep -m1 -o 'The request signature we calculated does not match the signature you provided. Check your key and signing method. (S3_ERROR)'
-$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_3)) SETTINGS base_backup=S3($(s3_location inc_1)), use_same_s3_credentials_for_base_backup=1" | cut -f2
 
+echo "inc_2"
+$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_2)) SETTINGS base_backup=S3($(s3_location inc_1))" | cut -f2
+
+echo "inc_3_bad"
+$CLICKHOUSE_CLIENT --format Null -q "BACKUP TABLE data TO S3($(s3_location inc_3_bad)) SETTINGS base_backup=S3($(s3_location_with_invalid_password inc_1))" |& grep -m1 -o 'The request signature we calculated does not match the signature you provided. Check your key and signing method. (S3_ERROR)'
+echo "inc_4"
+$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_4)) SETTINGS base_backup=S3($(s3_location_with_invalid_password inc_1)), use_same_s3_credentials_for_base_backup=1" | cut -f2
+
+echo "restore inc_1"
 $CLICKHOUSE_CLIENT --format Null -q "RESTORE TABLE data AS data FROM S3($(s3_location inc_1))" |& grep -m1 -o 'The request signature we calculated does not match the signature you provided. Check your key and signing method. (S3_ERROR)'
+echo "restore inc_1"
 $CLICKHOUSE_CLIENT -q "RESTORE TABLE data AS data_1 FROM S3($(s3_location inc_1)) SETTINGS use_same_s3_credentials_for_base_backup=1" | cut -f2
-$CLICKHOUSE_CLIENT -q "RESTORE TABLE data AS data_2 FROM S3($(s3_location inc_3)) SETTINGS use_same_s3_credentials_for_base_backup=1" | cut -f2
+echo "restore inc_2"
+$CLICKHOUSE_CLIENT -q "RESTORE TABLE data AS data_2 FROM S3($(s3_location inc_2)) SETTINGS use_same_s3_credentials_for_base_backup=1" | cut -f2
 
 echo 'use_same_s3_credentials_for_base_backup for S3 (invalid arguments)'
-$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_4_bad)) SETTINGS base_backup=S3($(s3_location inc_1), 'foo'), use_same_s3_credentials_for_base_backup=1" |& cut -f2
+echo "inc_5_bad"
-$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_5_bad), 'foo') SETTINGS base_backup=S3($(s3_location inc_1)), use_same_s3_credentials_for_base_backup=1" |& grep -o -m1 NUMBER_OF_ARGUMENTS_DOESNT_MATCH
+$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_5_bad)) SETTINGS base_backup=S3($(s3_location inc_1), 'foo'), use_same_s3_credentials_for_base_backup=1" |& cut -f2
+echo "inc_6_bad"
+$CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO S3($(s3_location inc_6_bad), 'foo') SETTINGS base_backup=S3($(s3_location inc_1)), use_same_s3_credentials_for_base_backup=1" |& grep -o -m1 NUMBER_OF_ARGUMENTS_DOESNT_MATCH
 
 echo 'use_same_s3_credentials_for_base_backup for Disk'
+echo "backup_1"
 $CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO Disk('backups', '$CLICKHOUSE_DATABASE/backup_1') SETTINGS use_same_s3_credentials_for_base_backup=1" | cut -f2
+echo "backup_2"
 $CLICKHOUSE_CLIENT -q "BACKUP TABLE data TO Disk('backups', '$CLICKHOUSE_DATABASE/backup_2') SETTINGS use_same_s3_credentials_for_base_backup=1, base_backup=Disk('backups', '$CLICKHOUSE_DATABASE/backup_1')" |& grep -o -m1 BAD_ARGUMENTS
 
 exit 0

tests/queries/0_stateless/02910_nullable_enum_cast.reference

@@ -0,0 +1,4 @@
+\N
+\N
+A
+A

tests/queries/0_stateless/02910_nullable_enum_cast.sql

@@ -0,0 +1,4 @@
+SELECT CAST(materialize(CAST(NULL, 'Nullable(Enum(\'A\' = 1, \'B\' = 2))')), 'Nullable(String)');
+SELECT CAST(CAST(NULL, 'Nullable(Enum(\'A\' = 1, \'B\' = 2))'), 'Nullable(String)');
+SELECT CAST(materialize(CAST(1, 'Nullable(Enum(\'A\' = 1, \'B\' = 2))')), 'Nullable(String)');
+SELECT CAST(CAST(1, 'Nullable(Enum(\'A\' = 1, \'B\' = 2))'), 'Nullable(String)');

tests/queries/0_stateless/02915_lazy_loading_of_base_backups.reference

@@ -0,0 +1,12 @@
+BACKUP_CREATED
+BACKUP_CREATED
+BACKUP_CREATED
+RESTORED
+RESTORED
+RESTORED
+a	0	1
+b	1	1
+c	1	1
+r1	3	0
+r2	2	0
+r3	1	0

tests/queries/0_stateless/02915_lazy_loading_of_base_backups.sh

@@ -0,0 +1,85 @@
+#!/usr/bin/env bash
+
+CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CUR_DIR"/../shell_config.sh
+
+a_backup_id=${CLICKHOUSE_TEST_UNIQUE_NAME}_a
+a_backup="Disk('backups', '$a_backup_id')"
+
+b_backup_id=${CLICKHOUSE_TEST_UNIQUE_NAME}_b
+b_backup="Disk('backups', '$b_backup_id')"
+
+c_backup_id=${CLICKHOUSE_TEST_UNIQUE_NAME}_c
+c_backup="Disk('backups', '$c_backup_id')"
+
+${CLICKHOUSE_CLIENT} -nm --query "
+DROP TABLE IF EXISTS tbl1;
+DROP TABLE IF EXISTS tbl2;
+DROP TABLE IF EXISTS tbl3;
+"
+
+${CLICKHOUSE_CLIENT} -nm --query "
+CREATE TABLE tbl1 (a Int32) ENGINE = MergeTree() ORDER BY tuple();
+"
+
+# The following BACKUP command must write backup 'a'.
+${CLICKHOUSE_CLIENT} -nm --query "
+BACKUP DATABASE ${CLICKHOUSE_DATABASE} TO $a_backup SETTINGS id='$a_backup_id';
+" | grep -o "BACKUP_CREATED"
+
+${CLICKHOUSE_CLIENT} -nm --query "
+CREATE TABLE tbl2 (a Int32) ENGINE = MergeTree() ORDER BY tuple();
+"
+
+# The following BACKUP command must read backup 'a' and write backup 'b'.
+${CLICKHOUSE_CLIENT} -nm --query "
+BACKUP DATABASE ${CLICKHOUSE_DATABASE} TO $b_backup SETTINGS id='$b_backup_id', base_backup=$a_backup;
+" | grep -o "BACKUP_CREATED"
+
+${CLICKHOUSE_CLIENT} -nm --query "
+CREATE TABLE tbl3 (a Int32) ENGINE = MergeTree() ORDER BY tuple();
+"
+
+# The following BACKUP command must read only backup 'b' (and not 'a') and write backup 'c'.
+${CLICKHOUSE_CLIENT} -nm --query "
+BACKUP DATABASE ${CLICKHOUSE_DATABASE} TO $c_backup SETTINGS id='$c_backup_id', base_backup=$b_backup;
+" | grep -o "BACKUP_CREATED"
+
+${CLICKHOUSE_CLIENT} -nm --query "
+DROP TABLE tbl1;
+DROP TABLE tbl2;
+DROP TABLE tbl3;
+"
+
+r1_restore_id=${CLICKHOUSE_TEST_UNIQUE_NAME}_r1
+r2_restore_id=${CLICKHOUSE_TEST_UNIQUE_NAME}_r2
+r3_restore_id=${CLICKHOUSE_TEST_UNIQUE_NAME}_r3
+
+# The following RESTORE command must read all 3 backups 'a', 'b', c' because the table 'tbl1' was in the first backup.
+${CLICKHOUSE_CLIENT} -nm --query "
+RESTORE TABLE ${CLICKHOUSE_DATABASE}.tbl1 FROM $c_backup SETTINGS id='$r1_restore_id';
+" | grep -o "RESTORED"
+
+# The following RESTORE command must read only 2 backups 'b', c' (and not 'a') because the table 'tbl2' was in the second backup.
+${CLICKHOUSE_CLIENT} -nm --query "
+RESTORE TABLE ${CLICKHOUSE_DATABASE}.tbl2 FROM $c_backup SETTINGS id='$r2_restore_id';
+" | grep -o "RESTORED"
+
+# The following RESTORE command must read only 1 backup 'c' (and not 'a' or 'b') because the table 'tbl3' was in the third backup.
+${CLICKHOUSE_CLIENT} -nm --query "
+RESTORE TABLE ${CLICKHOUSE_DATABASE}.tbl3 FROM $c_backup SETTINGS id='$r3_restore_id';
+" | grep -o "RESTORED"
+
+all_ids="['$a_backup_id', '$b_backup_id', '$c_backup_id', '$r1_restore_id', '$r2_restore_id', '$r3_restore_id']"
+id_prefix_len=`expr "${CLICKHOUSE_TEST_UNIQUE_NAME}_" : '.*'`
+
+${CLICKHOUSE_CLIENT} -nm --query "
+SELECT substr(id, 1 + $id_prefix_len) as short_id, ProfileEvents['BackupsOpenedForRead'], ProfileEvents['BackupsOpenedForWrite'] FROM system.backups WHERE id IN ${all_ids} ORDER BY short_id
+"
+
+${CLICKHOUSE_CLIENT} -nm --query "
+DROP TABLE tbl1;
+DROP TABLE tbl2;
+DROP TABLE tbl3;
+"

utils/check-style/check-style

@@ -394,6 +394,11 @@ find $ROOT_PATH/{src,programs,utils} -name '*.h' -or -name '*.cpp' |
     grep -vP $EXCLUDE_DIRS |
     xargs grep -P '__builtin_unreachable' && echo "Use UNREACHABLE() from defines.h instead"
 
+# Forbid mt19937() and random_device() which are outdated and slow
+find $ROOT_PATH/{src,programs,utils} -name '*.h' -or -name '*.cpp' |
+    grep -vP $EXCLUDE_DIRS |
+    xargs grep -P '(std::mt19937|std::mersenne_twister_engine|std::random_device)' && echo "Use pcg64_fast (from pcg_random.h) and randomSeed (from Common/randomSeed.h) instead"
+
 # Require checking return value of close(),
 # since it can hide fd misuse and break other places.
 find $ROOT_PATH/{src,programs,utils} -name '*.h' -or -name '*.cpp' |