Merge branch 'master' into rabbitmq-allow-multiple-hosts

docker/packager/binary/Dockerfile

@@ -42,15 +42,12 @@ RUN apt-get update \
         clang-tidy-10 \
         clang-tidy-11 \
         cmake \
-        cmake \
         curl \
         g++-9 \
         gcc-9 \
         gdb \
         git \
         gperf \
-        gperf \
-        intel-opencl-icd \
         libicu-dev \
         libreadline-dev \
         lld-10 \
@@ -61,10 +58,7 @@ RUN apt-get update \
         llvm-11-dev \
         moreutils \
         ninja-build \
-        ocl-icd-libopencl1 \
-        opencl-headers \
         pigz \
-        pixz \
         rename \
         tzdata \
         --yes --no-install-recommends

docker/packager/unbundled/Dockerfile

@@ -35,9 +35,6 @@ RUN apt-get update \
         libjemalloc-dev \
         libmsgpack-dev \
         libcurl4-openssl-dev \
-        opencl-headers \
-        ocl-icd-libopencl1 \
-        intel-opencl-icd \
         unixodbc-dev \
         odbcinst \
         tzdata \

docker/test/stateless_unbundled/Dockerfile

@@ -14,9 +14,7 @@ RUN apt-get --allow-unauthenticated update -y \
             expect \
             gdb  \
             gperf \
-            gperf \
             heimdal-multidev \
-            intel-opencl-icd \
             libboost-filesystem-dev \
             libboost-iostreams-dev \
             libboost-program-options-dev \
@@ -50,9 +48,7 @@ RUN apt-get --allow-unauthenticated update -y \
             moreutils \
             ncdu \
             netcat-openbsd \
-            ocl-icd-libopencl1 \
             odbcinst \
-            opencl-headers \
             openssl \
             perl \
             pigz \

docs/en/development/build.md

@@ -27,53 +27,20 @@ Or cmake3 instead of cmake on older systems.
 
 On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-```bash 
+```bash
 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-gcc-10-for-builds}
+#### Use clang-11 for Builds
 
 ``` bash
 $ export CC=clang-11
 $ export CXX=clang++-11
 ```
 
-### Install GCC 10 {#install-gcc-10}
+Gcc can also be used though it is discouraged.
-
-We recommend building ClickHouse with clang-11, GCC-10 also supported, but it is not used for production builds.
-
-If you want to use GCC-10 there are several ways to install it.
-
-#### Install from Repository {#install-from-repository}
-
-On Ubuntu 19.10 or newer:
-
-    $ sudo apt-get update
-    $ sudo apt-get install gcc-10 g++-10
-
-#### Install from a PPA Package {#install-from-a-ppa-package}
-
-On older Ubuntu:
-
-``` bash
-$ sudo apt-get install software-properties-common
-$ sudo apt-add-repository ppa:ubuntu-toolchain-r/test
-$ sudo apt-get update
-$ sudo apt-get install gcc-10 g++-10
-```
-
-#### Install from Sources {#install-from-sources}
-
-See [utils/ci/build-gcc-from-sources.sh](https://github.com/ClickHouse/ClickHouse/blob/master/utils/ci/build-gcc-from-sources.sh)
-
-#### Use GCC 10 for Builds {#use-gcc-10-for-builds}
-
-``` bash
-$ export CC=gcc-10
-$ export CXX=g++-10
-```
 
 ### Checkout ClickHouse Sources {#checkout-clickhouse-sources}
 

docs/en/development/developer-instruction.md

@@ -131,17 +131,18 @@ ClickHouse uses several external libraries for building. All of them do not need
 
 ## C++ Compiler {#c-compiler}
 
-Compilers GCC starting from version 10 and Clang version 8 or above are supported for building ClickHouse.
+Compilers Clang starting from version 11 is supported for building ClickHouse.
 
-Official Yandex builds currently use GCC because it generates machine code of slightly better performance (yielding a difference of up to several percent according to our benchmarks). And Clang is more convenient for development usually. Though, our continuous integration (CI) platform runs checks for about a dozen of build combinations.
+Clang should be used instead of gcc. Though, our continuous integration (CI) platform runs checks for about a dozen of build combinations.
 
-To install GCC on Ubuntu run: `sudo apt install gcc g++`
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-Check the version of gcc: `gcc --version`. If it is below 10, then follow the instruction here: https://clickhouse.tech/docs/en/development/build/#install-gcc-10.
+```bash
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
 
-Mac OS X build is supported only for Clang. Just run `brew install llvm`
+Mac OS X build is also supported. Just run `brew install llvm`
 
-If you decide to use Clang, you can also install `libc++` and `lld`, if you know what it is. Using `ccache` is also recommended.
 
 ## The Building Process {#the-building-process}
 
@@ -152,14 +153,7 @@ Now that you are ready to build ClickHouse we recommend you to create a separate
 
 You can have several different directories (build_release, build_debug, etc.) for different types of build.
 
-While inside the `build` directory, configure your build by running CMake. Before the first run, you need to define environment variables that specify compiler (version 10 gcc compiler in this example).
+While inside the `build` directory, configure your build by running CMake. Before the first run, you need to define environment variables that specify compiler.
-
-Linux:
-
-    export CC=gcc-10 CXX=g++-10
-    cmake ..
-
-Mac OS X:
 
     export CC=clang CXX=clang++
     cmake ..

docs/en/development/style.md

@@ -701,7 +701,7 @@ But other things being equal, cross-platform or portable code is preferred.
 
 **2.** Language: C++20 (see the list of available [C++20 features](https://en.cppreference.com/w/cpp/compiler_support#C.2B.2B20_features)).
 
-**3.** Compiler: `gcc`. At this time (August 2020), the code is compiled using version 9.3. (It can also be compiled using `clang 8`.)
+**3.** Compiler: `clang`. At this time (April 2021), the code is compiled using clang version 11. (It can also be compiled using `gcc` version 10, but it's untested and not suitable for production usage).
 
 The standard library is used (`libc++`).
 
@@ -711,7 +711,7 @@ The standard library is used (`libc++`).
 
 The CPU instruction set is the minimum supported set among our servers. Currently, it is SSE 4.2.
 
-**6.** Use `-Wall -Wextra -Werror` compilation flags.
+**6.** Use `-Wall -Wextra -Werror` compilation flags. Also `-Weverything` is used with few exceptions.
 
 **7.** Use static linking with all libraries except those that are difficult to connect to statically (see the output of the `ldd` command).
 

docs/en/operations/performance-test.md

@@ -12,6 +12,7 @@ With this instruction you can run basic ClickHouse performance test on any serve
 3.  Copy the link to `clickhouse` binary for amd64 or aarch64.
 4.  ssh to the server and download it with wget:
 ```bash
+# These links are outdated, please obtain the fresh link from the "commits" page.
 # For amd64:
 wget https://clickhouse-builds.s3.yandex.net/0/e29c4c3cc47ab2a6c4516486c1b77d57e7d42643/clickhouse_build_check/gcc-10_relwithdebuginfo_none_bundled_unsplitted_disable_False_binary/clickhouse
 # For aarch64:

docs/en/operations/settings/settings.md

@@ -854,8 +854,6 @@ For example, when reading from a table, if it is possible to evaluate expression
 
 Default value: the number of physical CPU cores.
 
-If less than one SELECT query is normally run on a server at a time, set this parameter to a value slightly less than the actual number of processor cores.
-
 For queries that are completed quickly because of a LIMIT, you can set a lower ‘max_threads’. For example, if the necessary number of entries are located in every block and max_threads = 8, then 8 blocks are retrieved, although it would have been enough to read just one.
 
 The smaller the `max_threads` value, the less memory is consumed.

docs/en/operations/system-tables/replication_queue.md

@@ -15,16 +15,16 @@ Columns:
 -   `node_name` ([String](../../sql-reference/data-types/string.md)) — Node name in ZooKeeper.
 
 -   `type` ([String](../../sql-reference/data-types/string.md)) — Type of the task in the queue, one of:
-    - `GET_PART`       - Get the part from another replica.
+
-    - `ATTACH_PART`    - Attach the part, possibly from our own replica (if found in `detached` folder). 
+    -   `GET_PART` — Get the part from another replica.
-    You may think of it as a `GET_PART` with some optimisations as they're nearly identical.
+    -   `ATTACH_PART` — Attach the part, possibly from our own replica (if found in the `detached` folder). You may think of it as a `GET_PART` with some optimizations as they're nearly identical.
-    - `MERGE_PARTS`    - Merge the parts.
+    -   `MERGE_PARTS` — Merge the parts.
-    - `DROP_RANGE`     - Delete the parts in the specified partition in the specified number range.
+    -   `DROP_RANGE` — Delete the parts in the specified partition in the specified number range.
-    - `CLEAR_COLUMN`   - NOTE: Deprecated. Drop specific column from specified partition.
+    -   `CLEAR_COLUMN` — NOTE: Deprecated. Drop specific column from specified partition.
-    - `CLEAR_INDEX`    - NOTE: Deprecated. Drop specific index from specified partition.
+    -   `CLEAR_INDEX` — NOTE: Deprecated. Drop specific index from specified partition.
-    - `REPLACE_RANGE`  - Drop certain range of partitions and replace them by new ones
+    -   `REPLACE_RANGE` — Drop a certain range of parts and replace them with new ones.
-    - `MUTATE_PART`    - Apply one or several mutations to the part.
+    -   `MUTATE_PART` — Apply one or several mutations to the part.
-    - `ALTER_METADATA` - Apply alter modification according to global /metadata and /columns paths
+    -   `ALTER_METADATA` — Apply alter modification according to global /metadata and /columns paths.
 
 -   `create_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — Date and time when the task was submitted for execution.
 

docs/en/sql-reference/statements/alter/partition.md

@@ -88,12 +88,10 @@ Read more about setting the partition expression in a section [How to specify th
 This query is replicated. The replica-initiator checks whether there is data in the `detached` directory. 
 If data exists, the query checks its integrity. If everything is correct, the query adds the data to the table.
 
-If the non-initiator replica, receiving the attach command, finds the part with the correct checksums in its own 
+If the non-initiator replica, receiving the attach command, finds the part with the correct checksums in its own `detached` folder, it attaches the data without fetching it from other replicas.
-`detached` folder, it attaches the data without fetching it from other replicas.
 If there is no part with the correct checksums, the data is downloaded from any replica having the part.
 
-You can put data to the `detached` directory on one replica and use the `ALTER ... ATTACH` query to add it to the 
+You can put data to the `detached` directory on one replica and use the `ALTER ... ATTACH` query to add it to the table on all replicas.
-table on all replicas.
 
 ## ATTACH PARTITION FROM {#alter_attach-partition-from}
 
@@ -101,8 +99,8 @@ table on all replicas.
 ALTER TABLE table2 ATTACH PARTITION partition_expr FROM table1
 ```
 
-This query copies the data partition from the `table1` to `table2`.
+This query copies the data partition from `table1` to `table2`.
-Note that data won't be deleted neither from `table1` nor from `table2`.
+Note that data will be deleted neither from `table1` nor from `table2`.
 
 For the query to run successfully, the following conditions must be met:
 

docs/en/sql-reference/statements/system.md

@@ -264,9 +264,7 @@ Wait until a `ReplicatedMergeTree` table will be synced with other replicas in a
 SYSTEM SYNC REPLICA [db.]replicated_merge_tree_family_table_name
 ```
 
-After running this statement the `[db.]replicated_merge_tree_family_table_name` fetches commands from
+After running this statement the `[db.]replicated_merge_tree_family_table_name` fetches commands from the common replicated log into its own replication queue, and then the query waits till the replica processes all of the fetched commands.
-the common replicated log into its own replication queue, and then the query waits till the replica processes all
-of the fetched commands.
 
 ### RESTART REPLICA {#query_language-system-restart-replica}
 

docs/ja/development/build.md

@@ -19,28 +19,17 @@ $ sudo apt-get install git cmake python ninja-build
 
 古いシステムではcmakeの代わりにcmake3。
 
-## GCC9のインストール {#install-gcc-10}
+## Clang 11 のインストール
 
-これを行うにはいくつかの方法があります。
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-### PPAパッケージからインストール {#install-from-a-ppa-package}
+```bash
-
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
-``` bash
-$ sudo apt-get install software-properties-common
-$ sudo apt-add-repository ppa:ubuntu-toolchain-r/test
-$ sudo apt-get update
-$ sudo apt-get install gcc-10 g++-10
 ```
 
-### ソースからインスト {#install-from-sources}
-
-見て [utils/ci/build-gcc-from-sources.sh](https://github.com/ClickHouse/ClickHouse/blob/master/utils/ci/build-gcc-from-sources.sh)
-
-## ビルドにGCC9を使用する {#use-gcc-10-for-builds}
-
 ``` bash
-$ export CC=gcc-10
+$ export CC=clang
-$ export CXX=g++-10
+$ export CXX=clang++
 ```
 
 ## ﾂつｨﾂ姪"ﾂ債ﾂつｹ {#checkout-clickhouse-sources}
@@ -76,7 +65,7 @@ $ cd ..
 -   Git（ソースをチェックアウトするためにのみ使用され、ビルドには必要ありません)
 -   CMake3.10以降
 -   忍者（推奨）または作る
--   C++コンパイラ:gcc9またはclang8以降
+-   C++コンパイラ:clang11以降
 -   リンカ:lldまたはgold(古典的なGNU ldは動作しません)
 -   Python(LLVMビルド内でのみ使用され、オプションです)
 

docs/ja/development/developer-instruction.md

@@ -133,19 +133,19 @@ ArchまたはGentooを使用する場合は、おそらくCMakeのインスト
 
 ClickHouseはビルドに複数の外部ライブラリを使用します。 それらのすべては、サブモジュールにあるソースからClickHouseと一緒に構築されているので、別々にインストールする必要はありません。 リストは次の場所で確認できます `contrib`.
 
-# C++コンパイラ {#c-compiler}
+## C++ Compiler {#c-compiler}
 
-ClickHouseのビルドには、バージョン9以降のGCCとClangバージョン8以降のコンパイラがサポートされます。
+Compilers Clang starting from version 11 is supported for building ClickHouse.
 
-公式のYandexビルドは、わずかに優れたパフォーマンスのマシンコードを生成するため、GCCを使用しています（私たちのベンチマークに応じて最大数パーセントの そしてClangは開発のために通常より便利です。 が、当社の継続的インテグレーション（CI)プラットフォームを運チェックのための十数の組み合わせとなります。
+Clang should be used instead of gcc. Though, our continuous integration (CI) platform runs checks for about a dozen of build combinations.
 
-UBUNTUにGCCをインストールするには: `sudo apt install gcc g++`
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-Gccのバージョンを確認する: `gcc --version`. の場合は下記9その指示に従う。https://clickhouse.tech/docs/ja/development/build/#install-gcc-10.
+```bash
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
 
-Mac OS XのビルドはClangでのみサポートされています。 ちょうど実行 `brew install llvm`
+Mac OS X build is also supported. Just run `brew install llvm`
-
-Clangを使用する場合は、次のものもインストールできます `libc++` と `lld` あなたがそれが何であるか知っていれば。 を使用して `ccache` また、推奨されます。
 
 # 建築プロセス {#the-building-process}
 
@@ -158,13 +158,6 @@ ClickHouseを構築する準備ができたので、別のディレクトリを
 
 中の間 `build` cmakeを実行してビルドを構成します。 最初の実行の前に、コンパイラ（この例ではバージョン9gccコンパイラ）を指定する環境変数を定義する必要があります。
 
-Linux:
-
-    export CC=gcc-10 CXX=g++-10
-    cmake ..
-
-Mac OS X:
-
     export CC=clang CXX=clang++
     cmake ..
 

docs/ru/development/developer-instruction.md

@@ -136,18 +136,18 @@ ClickHouse использует для сборки некоторое коли
 
 ## Компилятор C++ {#kompiliator-c}
 
-В качестве компилятора C++ поддерживается GCC начиная с версии 9 или Clang начиная с версии 8.
+В качестве компилятора C++ поддерживается Clang начиная с версии 11.
 
-Официальные сборки от Яндекса, на данный момент, используют GCC, так как он генерирует слегка более производительный машинный код (разница в среднем до нескольких процентов по нашим бенчмаркам). Clang обычно более удобен для разработки. Впрочем, наша среда continuous integration проверяет около десятка вариантов сборки.
+Впрочем, наша среда continuous integration проверяет около десятка вариантов сборки, включая gcc, но сборка с помощью gcc непригодна для использования в продакшене.
 
-Для установки GCC под Ubuntu, выполните: `sudo apt install gcc g++`.
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-Проверьте версию gcc: `gcc --version`. Если версия меньше 10, то следуйте инструкции: https://clickhouse.tech/docs/ru/development/build/#install-gcc-10.
+```bash
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
+```
 
 Сборка под Mac OS X поддерживается только для компилятора Clang. Чтобы установить его выполните `brew install llvm`
 
-Если вы решили использовать Clang, вы также можете установить `libc++` и `lld`, если вы знаете, что это такое. При желании, установите `ccache`.
-
 ## Процесс сборки {#protsess-sborki}
 
 Теперь вы готовы к сборке ClickHouse. Для размещения собранных файлов, рекомендуется создать отдельную директорию build внутри директории ClickHouse:
@@ -158,14 +158,7 @@ ClickHouse использует для сборки некоторое коли
 Вы можете иметь несколько разных директорий (build_release, build_debug) для разных вариантов сборки.
 
 Находясь в директории build, выполните конфигурацию сборки с помощью CMake.
-Перед первым запуском необходимо выставить переменные окружения, отвечающие за выбор компилятора (в данном примере это - gcc версии 9).
+Перед первым запуском необходимо выставить переменные окружения, отвечающие за выбор компилятора.
-
-Linux:
-
-    export CC=gcc-10 CXX=g++-10
-    cmake ..
-
-Mac OS X:
 
     export CC=clang CXX=clang++
     cmake ..

docs/ru/development/style.md

@@ -747,7 +747,7 @@ The dictionary is configured incorrectly.
 Есть два основных варианта проверки на такие ошибки:
 
 * Исключение с кодом `LOGICAL_ERROR`. Его можно использовать для важных проверок, которые делаются в том числе в релизной сборке.
-* `assert`. Такие условия не проверяются в релизной сборке, можно использовать для тяжёлых и опциональных проверок.	
+* `assert`. Такие условия не проверяются в релизной сборке, можно использовать для тяжёлых и опциональных проверок.
 
 Пример сообщения, у которого должен быть код `LOGICAL_ERROR`:
 `Block header is inconsistent with Chunk in ICompicatedProcessor::munge(). It is a bug!`
@@ -780,7 +780,7 @@ The dictionary is configured incorrectly.
 
 **2.** Язык - C++20 (см. список доступных [C++20 фич](https://en.cppreference.com/w/cpp/compiler_support#C.2B.2B20_features)).
 
-**3.** Компилятор - `gcc`. На данный момент (август 2020), код собирается версией 9.3. (Также код может быть собран `clang` версий 10 и 9)
+**3.** Компилятор - `clang`. На данный момент (апрель 2021), код собирается версией 11. (Также код может быть собран `gcc` версии 10, но такая сборка не тестируется и непригодна для продакшена).
 
 Используется стандартная библиотека (реализация `libc++`).
 

docs/ru/operations/settings/settings.md

@@ -844,8 +844,6 @@ SELECT type, query FROM system.query_log WHERE log_comment = 'log_comment test'
 
 Значение по умолчанию: количество процессорных ядер без учёта Hyper-Threading.
 
-Если на сервере обычно исполняется менее одного запроса SELECT одновременно, то выставите этот параметр в значение чуть меньше количества реальных процессорных ядер.
-
 Для запросов, которые быстро завершаются из-за LIMIT-а, имеет смысл выставить max_threads поменьше. Например, если нужное количество записей находится в каждом блоке, то при max_threads = 8 будет считано 8 блоков, хотя достаточно было прочитать один.
 
 Чем меньше `max_threads`, тем меньше будет использоваться оперативки.

docs/ru/operations/system-tables/replication_queue.md

@@ -14,7 +14,17 @@
 
 -   `node_name` ([String](../../sql-reference/data-types/string.md)) — имя узла в ZooKeeper.
 
--   `type` ([String](../../sql-reference/data-types/string.md)) — тип задачи в очереди: `GET_PARTS`, `MERGE_PARTS`, `DETACH_PARTS`, `DROP_PARTS` или `MUTATE_PARTS`.
+-   `type` ([String](../../sql-reference/data-types/string.md)) — тип задачи в очереди:
+
+    -   `GET_PART` — скачать кусок с другой реплики.
+    -   `ATTACH_PART` — присоединить кусок. Задача может быть выполнена и с куском из нашей собственной реплики (если он находится в папке `detached`). Эта задача практически идентична задаче `GET_PART`, лишь немного оптимизирована.
+    -   `MERGE_PARTS` — выполнить слияние кусков.
+    -   `DROP_RANGE` — удалить куски в партициях из указнного диапазона.
+    -   `CLEAR_COLUMN` — удалить указанный столбец из указанной партиции. Примечание: не используется с 20.4.
+    -   `CLEAR_INDEX` — удалить указанный индекс из указанной партиции. Примечание: не используется с 20.4. 
+    -   `REPLACE_RANGE` — удалить указанный диапазон кусков и заменить их на новые.
+    -   `MUTATE_PART` — применить одну или несколько мутаций к куску.
+    -   `ALTER_METADATA` — применить изменения структуры таблицы в результате запросов с выражением `ALTER`.
 
 -   `create_time` ([Datetime](../../sql-reference/data-types/datetime.md)) — дата и время отправки задачи на выполнение.
 
@@ -77,4 +87,3 @@ last_postpone_time:     1970-01-01 03:00:00
 **Смотрите также**
 
 -   [Управление таблицами ReplicatedMergeTree](../../sql-reference/statements/system.md#query-language-system-replicated)
-

docs/ru/operations/system-tables/trace_log.md

@@ -18,10 +18,12 @@ ClickHouse создает эту таблицу когда утсановлен
 
         Во время соединения с сервером через `clickhouse-client`, вы видите строку похожую на `Connected to ClickHouse server version 19.18.1 revision 54429.`. Это поле содержит номер после `revision`, но не содержит строку после `version`.
 
--   `timer_type`([Enum8](../../sql-reference/data-types/enum.md)) — тип таймера:
+-   `trace_type`([Enum8](../../sql-reference/data-types/enum.md)) — тип трассировки:
 
-        - `Real` означает wall-clock время.
+    -   `Real` — сбор трассировок стека адресов вызова по времени wall-clock.
-        - `CPU` означает относительное CPU время.
+    -   `CPU` — сбор трассировок стека адресов вызова по времени CPU.
+    -   `Memory` — сбор выделенной памяти, когда ее размер превышает относительный инкремент.
+    -   `MemorySample` — сбор случайно выделенной памяти.
 
 -   `thread_number`([UInt32](../../sql-reference/data-types/int-uint.md)) — идентификатор треда.
 

docs/ru/sql-reference/statements/alter/partition.md

@@ -38,7 +38,7 @@ ALTER TABLE mt DETACH PART 'all_2_2_0';
 
 После того как запрос будет выполнен, вы сможете производить любые операции с данными в директории `detached`. Например, можно удалить их из файловой системы.
 
-Запрос реплицируется — данные будут перенесены в директорию `detached` и забыты на всех репликах. Обратите внимание, запрос может быть отправлен только на реплику-лидер. Чтобы узнать, является ли реплика лидером, выполните запрос `SELECT` к системной таблице [system.replicas](../../../operations/system-tables/replicas.md#system_tables-replicas). Либо можно выполнить запрос `DETACH` на всех репликах — тогда на всех репликах, кроме реплики-лидера, запрос вернет ошибку.
+Запрос реплицируется — данные будут перенесены в директорию `detached` и забыты на всех репликах. Обратите внимание, запрос может быть отправлен только на реплику-лидер. Чтобы узнать, является ли реплика лидером, выполните запрос `SELECT` к системной таблице [system.replicas](../../../operations/system-tables/replicas.md#system_tables-replicas). Либо можно выполнить запрос `DETACH` на всех репликах — тогда на всех репликах, кроме реплик-лидеров (поскольку допускается несколько лидеров), запрос вернет ошибку.
 
 ## DROP PARTITION\|PART {#alter_drop-partition}
 
@@ -83,9 +83,13 @@ ALTER TABLE visits ATTACH PART 201901_2_2_0;
 
 Как корректно задать имя партиции или куска, см. в разделе [Как задавать имя партиции в запросах ALTER](#alter-how-to-specify-part-expr).
 
-Этот запрос реплицируется. Реплика-иницатор проверяет, есть ли данные в директории `detached`. Если данные есть, то запрос проверяет их целостность. В случае успеха данные добавляются в таблицу. Все остальные реплики загружают данные с реплики-инициатора запроса.
+Этот запрос реплицируется. Реплика-иницатор проверяет, есть ли данные в директории `detached`.
+Если данные есть, то запрос проверяет их целостность. В случае успеха данные добавляются в таблицу.
 
-Это означает, что вы можете разместить данные в директории `detached` на одной реплике и с помощью запроса `ALTER ... ATTACH` добавить их в таблицу на всех репликах.
+Если реплика, не являющаяся инициатором запроса, получив команду присоединения, находит кусок с правильными контрольными суммами в своей собственной папке `detached`, она присоединяет данные, не скачивая их с других реплик.
+Если нет куска с правильными контрольными суммами, данные загружаются из любой реплики, имеющей этот кусок.
+
+Вы можете поместить данные в директорию `detached` на одной реплике и с помощью запроса `ALTER ... ATTACH` добавить их в таблицу на всех репликах.
 
 ## ATTACH PARTITION FROM {#alter_attach-partition-from}
 
@@ -93,7 +97,8 @@ ALTER TABLE visits ATTACH PART 201901_2_2_0;
 ALTER TABLE table2 ATTACH PARTITION partition_expr FROM table1
 ```
 
-Копирует партицию из таблицы `table1` в таблицу `table2` и добавляет к существующим данным `table2`. Данные из `table1` не удаляются.
+Копирует партицию из таблицы `table1` в таблицу `table2`.
+Обратите внимание, что данные не удаляются ни из `table1`, ни из `table2`.
 
 Следует иметь в виду:
 
@@ -305,4 +310,3 @@ OPTIMIZE TABLE table_not_partitioned PARTITION tuple() FINAL;
 `IN PARTITION` указывает на партицию, для которой применяются выражения [UPDATE](../../../sql-reference/statements/alter/update.md#alter-table-update-statements) или [DELETE](../../../sql-reference/statements/alter/delete.md#alter-mutations) в результате запроса `ALTER TABLE`. Новые куски создаются только в указанной партиции. Таким образом, `IN PARTITION` помогает снизить нагрузку, когда таблица разбита на множество партиций, а вам нужно обновить данные лишь точечно.
 
 Примеры запросов `ALTER ... PARTITION` можно посмотреть в тестах: [`00502_custom_partitioning_local`](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00502_custom_partitioning_local.sql) и [`00502_custom_partitioning_replicated_zookeeper`](https://github.com/ClickHouse/ClickHouse/blob/master/tests/queries/0_stateless/00502_custom_partitioning_replicated_zookeeper.sql).
-

docs/ru/sql-reference/statements/system.md

@@ -204,6 +204,7 @@ SYSTEM STOP MOVES [[db.]merge_tree_family_table_name]
 ClickHouse может управлять фоновыми процессами связанными c репликацией в таблицах семейства [ReplicatedMergeTree](../../engines/table-engines/mergetree-family/replacingmergetree.md).
 
 ### STOP FETCHES {#query_language-system-stop-fetches}
+
 Позволяет остановить фоновые процессы синхронизации новыми вставленными кусками данных с другими репликами в кластере для таблиц семейства `ReplicatedMergeTree`:
 Всегда возвращает `Ok.` вне зависимости от типа таблицы и даже если таблица или база данных не существет.
 
@@ -212,6 +213,7 @@ SYSTEM STOP FETCHES [[db.]replicated_merge_tree_family_table_name]
 ```
 
 ### START FETCHES {#query_language-system-start-fetches}
+
 Позволяет запустить фоновые процессы синхронизации новыми вставленными кусками данных с другими репликами в кластере для таблиц семейства `ReplicatedMergeTree`:
 Всегда возвращает `Ok.` вне зависимости от типа таблицы и даже если таблица или база данных не существет.
 
@@ -220,6 +222,7 @@ SYSTEM START FETCHES [[db.]replicated_merge_tree_family_table_name]
 ```
 
 ### STOP REPLICATED SENDS {#query_language-system-start-replicated-sends}
+
 Позволяет остановить фоновые процессы отсылки новых вставленных кусков данных другим репликам в кластере для таблиц семейства `ReplicatedMergeTree`:
 
 ``` sql
@@ -227,6 +230,7 @@ SYSTEM STOP REPLICATED SENDS [[db.]replicated_merge_tree_family_table_name]
 ```
 
 ### START REPLICATED SENDS {#query_language-system-start-replicated-sends}
+
 Позволяет запустить фоновые процессы отсылки новых вставленных кусков данных другим репликам в кластере для таблиц семейства `ReplicatedMergeTree`:
 
 ``` sql
@@ -234,6 +238,7 @@ SYSTEM START REPLICATED SENDS [[db.]replicated_merge_tree_family_table_name]
 ```
 
 ### STOP REPLICATION QUEUES {#query_language-system-stop-replication-queues}
+
 Останавливает фоновые процессы разбора заданий из очереди репликации которая хранится в Zookeeper для таблиц семейства `ReplicatedMergeTree`. Возможные типы заданий - merges, fetches, mutation, DDL запросы с ON CLUSTER: 
 
 ``` sql
@@ -241,6 +246,7 @@ SYSTEM STOP REPLICATION QUEUES [[db.]replicated_merge_tree_family_table_name]
 ```
 
 ### START REPLICATION QUEUES {#query_language-system-start-replication-queues}
+
 Запускает фоновые процессы разбора заданий из очереди репликации которая хранится в Zookeeper для таблиц семейства `ReplicatedMergeTree`. Возможные типы заданий - merges, fetches, mutation, DDL запросы с ON CLUSTER: 
 
 ``` sql
@@ -248,20 +254,24 @@ SYSTEM START REPLICATION QUEUES [[db.]replicated_merge_tree_family_table_name]
 ```
 
 ### SYNC REPLICA {#query_language-system-sync-replica}
+
 Ждет когда таблица семейства `ReplicatedMergeTree` будет синхронизирована с другими репликами в кластере, будет работать до достижения `receive_timeout`, если синхронизация для таблицы отключена в настоящий момент времени:  
 
 ``` sql
 SYSTEM SYNC REPLICA [db.]replicated_merge_tree_family_table_name
 ```
 
+После выполнения этого запроса таблица `[db.]replicated_merge_tree_family_table_name` синхронизирует команды из общего реплицированного лога в свою собственную очередь репликации. Затем запрос ждет, пока реплика не обработает все синхронизированные команды.
+
 ### RESTART REPLICA {#query_language-system-restart-replica}
-Реинициализация состояния Zookeeper сессий для таблицы семейства `ReplicatedMergeTree`, сравнивает текущее состояние с тем что хранится в Zookeeper как источник правды и добавляет задачи Zookeeper очередь если необходимо  
+
-Инициализация очереди репликации на основе данных ZooKeeper, происходит так же как при attach table. На короткое время таблица станет недоступной для любых операций.
+Реинициализация состояния Zookeeper-сессий для таблицы семейства `ReplicatedMergeTree`. Сравнивает текущее состояние с тем, что хранится в Zookeeper, как источник правды, и добавляет задачи в очередь репликации в Zookeeper, если необходимо.
+Инициализация очереди репликации на основе данных ZooKeeper происходит так же, как при attach table. На короткое время таблица станет недоступной для любых операций.
 
 ``` sql
 SYSTEM RESTART REPLICA [db.]replicated_merge_tree_family_table_name
 ```
 
 ### RESTART REPLICAS {#query_language-system-restart-replicas}
-Реинициализация состояния Zookeeper сессий для всех `ReplicatedMergeTree` таблиц, сравнивает текущее состояние с тем что хранится в Zookeeper как источник правды и добавляет задачи Zookeeper очередь если необходимо
 
+Реинициализация состояния ZooKeeper-сессий для всех `ReplicatedMergeTree` таблиц. Сравнивает текущее состояние реплики с тем, что хранится в ZooKeeper, как c источником правды, и добавляет задачи в очередь репликации в ZooKeeper, если необходимо.

docs/zh/development/build.md

@@ -35,28 +35,12 @@ sudo apt-get install git cmake ninja-build
 或cmake3而不是旧系统上的cmake。
 或者在早期版本的系统中用 cmake3 替代 cmake
 
-## 安装 GCC 10 {#an-zhuang-gcc-10}
+## 安装 Clang
 
-有几种方法可以做到这一点。
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-### 安装 PPA 包 {#an-zhuang-ppa-bao}
+```bash
-
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
-``` bash
-sudo apt-get install software-properties-common
-sudo apt-add-repository ppa:ubuntu-toolchain-r/test
-sudo apt-get update
-sudo apt-get install gcc-10 g++-10
-```
-
-### 源码安装 gcc {#yuan-ma-an-zhuang-gcc}
-
-请查看 [utils/ci/build-gcc-from-sources.sh](https://github.com/ClickHouse/ClickHouse/blob/master/utils/ci/build-gcc-from-sources.sh)
-
-## 使用 GCC 10 来编译 {#shi-yong-gcc-10-lai-bian-yi}
-
-``` bash
-export CC=gcc-10
-export CXX=g++-10
 ```
 
 ## 拉取 ClickHouse 源码 {#la-qu-clickhouse-yuan-ma-1}

docs/zh/development/developer-instruction.md

@@ -123,17 +123,13 @@ ClickHouse使用多个外部库进行构建。大多数外部库不需要单独
 
 # C++ 编译器 {#c-bian-yi-qi}
 
-GCC编译器从版本9开始，以及Clang版本\>=8都可支持构建ClickHouse。
+We support clang starting from version 11.
 
-Yandex官方当前使用GCC构建ClickHouse，因为它生成的机器代码性能较好（根据测评，最多可以相差几个百分点）。Clang通常可以更加便捷的开发。我们的持续集成（CI）平台会运行大约十二种构建组合的检查。
+On Ubuntu/Debian you can use the automatic installation script (check [official webpage](https://apt.llvm.org/))
 
-在Ubuntu上安装GCC，请执行：`sudo apt install gcc g++`
+```bash
-
+sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
-请使用`gcc --version`查看gcc的版本。如果gcc版本低于9，请参考此处的指示：https://clickhouse.tech/docs/zh/development/build/#an-zhuang-gcc-10 。
+```
-
-在Mac OS X上安装GCC，请执行：`brew install gcc`
-
-如果您决定使用Clang，还可以同时安装 `libc++`以及`lld`，前提是您也熟悉它们。此外，也推荐使用`ccache`。
 
 # 构建的过程 {#gou-jian-de-guo-cheng}
 
@@ -146,7 +142,7 @@ Yandex官方当前使用GCC构建ClickHouse，因为它生成的机器代码性
 
 在`build`目录下，通过运行CMake配置构建。 在第一次运行之前，请定义用于指定编译器的环境变量（本示例中为gcc 9 编译器）。
 
-    export CC=gcc-10 CXX=g++-10
+    export CC=clang CXX=clang++
     cmake ..
 
 `CC`变量指代C的编译器（C Compiler的缩写），而`CXX`变量指代要使用哪个C++编译器进行编译。

docs/zh/development/style.md

@@ -696,7 +696,7 @@ auto s = std::string{"Hello"};
 
 **2.** 语言： C++20.
 
-**3.** 编译器： `gcc`。 此时（2020年08月），代码使用9.3版编译。（它也可以使用`clang 8` 编译）
+**3.** 编译器： `clang`。 此时（2021年03月），代码使用11版编译。（它也可以使用`gcc` 编译 but it is not suitable for production）
 
 使用标准库 (`libc++`)。
 

src/DataTypes/IDataType.h

@@ -360,7 +360,8 @@ inline bool isEnum(const DataTypePtr & data_type) { return WhichDataType(data_ty
 inline bool isDecimal(const DataTypePtr & data_type) { return WhichDataType(data_type).isDecimal(); }
 inline bool isTuple(const DataTypePtr & data_type) { return WhichDataType(data_type).isTuple(); }
 inline bool isArray(const DataTypePtr & data_type) { return WhichDataType(data_type).isArray(); }
-inline bool isMap(const DataTypePtr & data_type) {return WhichDataType(data_type).isMap(); }
+inline bool isMap(const DataTypePtr & data_type) { return WhichDataType(data_type).isMap(); }
+inline bool isNothing(const DataTypePtr & data_type) { return WhichDataType(data_type).isNothing(); }
 
 template <typename T>
 inline bool isUInt8(const T & data_type)

src/Functions/FunctionsConversion.h

@@ -2496,7 +2496,7 @@ private:
         }
     }
 
-    WrapperType createArrayWrapper(const DataTypePtr & from_type_untyped, const DataTypeArray * to_type) const
+    WrapperType createArrayWrapper(const DataTypePtr & from_type_untyped, const DataTypeArray & to_type) const
     {
         /// Conversion from String through parsing.
         if (checkAndGetDataType<DataTypeString>(from_type_untyped.get()))
@@ -2507,24 +2507,23 @@ private:
             };
         }
 
-        DataTypePtr from_nested_type;
-        DataTypePtr to_nested_type;
         const auto * from_type = checkAndGetDataType<DataTypeArray>(from_type_untyped.get());
-
+        if (!from_type)
-        /// get the most nested type
-        if (from_type && to_type)
         {
-            from_nested_type = from_type->getNestedType();
+            throw Exception(ErrorCodes::TYPE_MISMATCH,
-            to_nested_type = to_type->getNestedType();
+                "CAST AS Array can only be perforamed between same-dimensional Array or String types");
-
-            from_type = checkAndGetDataType<DataTypeArray>(from_nested_type.get());
-            to_type = checkAndGetDataType<DataTypeArray>(to_nested_type.get());
         }
 
-        /// both from_type and to_type should be nullptr now is array types had same dimensions
+        DataTypePtr from_nested_type = from_type->getNestedType();
-        if ((from_type == nullptr) != (to_type == nullptr))
+
-            throw Exception{"CAST AS Array can only be performed between same-dimensional array types or from String",
+        /// In query SELECT CAST([] AS Array(Array(String))) from type is Array(Nothing)
-                ErrorCodes::TYPE_MISMATCH};
+        bool from_empty_array = isNothing(from_nested_type);
+
+        if (from_type->getNumberOfDimensions() != to_type.getNumberOfDimensions() && !from_empty_array)
+            throw Exception(ErrorCodes::TYPE_MISMATCH,
+                "CAST AS Array can only be perforamed between same-dimensional array types");
+
+        const DataTypePtr & to_nested_type = to_type.getNestedType();
 
         /// Prepare nested type conversion
         const auto nested_function = prepareUnpackDictionaries(from_nested_type, to_nested_type);
@@ -3090,14 +3089,12 @@ private:
                 return createStringWrapper(from_type);
             case TypeIndex::FixedString:
                 return createFixedStringWrapper(from_type, checkAndGetDataType<DataTypeFixedString>(to_type.get())->getN());
-
             case TypeIndex::Array:
-                return createArrayWrapper(from_type, checkAndGetDataType<DataTypeArray>(to_type.get()));
+                return createArrayWrapper(from_type, static_cast<const DataTypeArray &>(*to_type));
             case TypeIndex::Tuple:
                 return createTupleWrapper(from_type, checkAndGetDataType<DataTypeTuple>(to_type.get()));
             case TypeIndex::Map:
                 return createMapWrapper(from_type, checkAndGetDataType<DataTypeMap>(to_type.get()));
-
             case TypeIndex::AggregateFunction:
                 return createAggregateFunctionWrapper(from_type, checkAndGetDataType<DataTypeAggregateFunction>(to_type.get()));
             default:

src/Processors/Formats/Impl/ArrowBlockInputFormat.cpp

@@ -24,7 +24,6 @@ namespace ErrorCodes
 ArrowBlockInputFormat::ArrowBlockInputFormat(ReadBuffer & in_, const Block & header_, bool stream_)
     : IInputFormat(header_, in_), stream{stream_}
 {
-    prepareReader();
 }
 
 Chunk ArrowBlockInputFormat::generate()
@@ -35,12 +34,18 @@ Chunk ArrowBlockInputFormat::generate()
 
     if (stream)
     {
+        if (!stream_reader)
+            prepareReader();
+
         batch_result = stream_reader->Next();
         if (batch_result.ok() && !(*batch_result))
             return res;
     }
     else
     {
+        if (!file_reader)
+            prepareReader();
+
         if (record_batch_current >= record_batch_total)
             return res;
 
@@ -71,7 +76,7 @@ void ArrowBlockInputFormat::resetParser()
         stream_reader.reset();
     else
         file_reader.reset();
-    prepareReader();
+    record_batch_current = 0;
 }
 
 void ArrowBlockInputFormat::prepareReader()

src/Storages/System/IStorageSystemOneBlock.h

@@ -12,7 +12,16 @@ namespace DB
 class Context;
 
 
-/** Base class for system tables whose all columns have String type.
+/** IStorageSystemOneBlock is base class for system tables whose all columns can be synchronously fetched.
+  *
+  * Client class need to provide static method static NamesAndTypesList getNamesAndTypes() that will return list of column names and
+  * their types. IStorageSystemOneBlock during read will create result columns in same order as result of getNamesAndTypes
+  * and pass it with fillData method.
+  *
+  * Client also must override fillData and fill result columns.
+  *
+  * If subclass want to support virtual columns, it should override getVirtuals method of IStorage interface.
+  * IStorageSystemOneBlock will add virtuals columns at the end of result columns of fillData method.
   */
 template <typename Self>
 class IStorageSystemOneBlock : public IStorage
@@ -41,9 +50,10 @@ public:
         size_t /*max_block_size*/,
         unsigned /*num_streams*/) override
     {
-        metadata_snapshot->check(column_names, getVirtuals(), getStorageID());
+        auto virtuals_names_and_types = getVirtuals();
+        metadata_snapshot->check(column_names, virtuals_names_and_types, getStorageID());
 
-        Block sample_block = metadata_snapshot->getSampleBlock();
+        Block sample_block = metadata_snapshot->getSampleBlockWithVirtuals(virtuals_names_and_types);
         MutableColumns res_columns = sample_block.cloneEmptyColumns();
         fillData(res_columns, context, query_info);
 

src/Storages/System/StorageSystemDictionaries.cpp

@@ -50,6 +50,13 @@ NamesAndTypesList StorageSystemDictionaries::getNamesAndTypes()
     };
 }
 
+NamesAndTypesList StorageSystemDictionaries::getVirtuals() const
+{
+    return {
+        {"key", std::make_shared<DataTypeString>()}
+    };
+}
+
 void StorageSystemDictionaries::fillData(MutableColumns & res_columns, ContextPtr context, const SelectQueryInfo & /*query_info*/) const
 {
     const auto access = context->getAccess();
@@ -128,6 +135,9 @@ void StorageSystemDictionaries::fillData(MutableColumns & res_columns, ContextPt
         else
             res_columns[i++]->insertDefault();
 
+        /// Start fill virtual columns
+
+        res_columns[i++]->insert(dictionary_structure.getKeyDescription());
     }
 }
 

src/Storages/System/StorageSystemDictionaries.h

@@ -18,6 +18,8 @@ public:
 
     static NamesAndTypesList getNamesAndTypes();
 
+    NamesAndTypesList getVirtuals() const override;
+
 protected:
     using IStorageSystemOneBlock::IStorageSystemOneBlock;
 

tests/queries/0_stateless/01837_cast_to_array_from_empty_array.reference

@@ -0,0 +1,2 @@
+[]
+[]

tests/queries/0_stateless/01837_cast_to_array_from_empty_array.sql

@@ -0,0 +1,2 @@
+SELECT CAST([] AS Array(Array(String)));
+SELECT CAST([] AS Array(Array(Array(String))));

tests/queries/0_stateless/01838_system_dictionaries_virtual_key_column.reference

@@ -0,0 +1,4 @@
+simple key
+example_simple_key_dictionary	UInt64
+complex key
+example_complex_key_dictionary	(UInt64, String)

tests/queries/0_stateless/01838_system_dictionaries_virtual_key_column.sql

@@ -0,0 +1,26 @@
+DROP DICTIONARY IF EXISTS example_simple_key_dictionary;
+CREATE DICTIONARY example_simple_key_dictionary (
+    id UInt64,
+    value UInt64
+)
+PRIMARY KEY id
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() USER 'default' TABLE '' DATABASE currentDatabase()))
+LAYOUT(DIRECT());
+
+SELECT 'simple key';
+
+SELECT name, key FROM system.dictionaries WHERE name='example_simple_key_dictionary' AND database=currentDatabase();
+
+DROP DICTIONARY IF EXISTS example_complex_key_dictionary;
+CREATE DICTIONARY example_complex_key_dictionary (
+    id UInt64,
+    id_key String,
+    value UInt64
+)
+PRIMARY KEY id, id_key
+SOURCE(CLICKHOUSE(HOST 'localhost' PORT tcpPort() USER 'default' TABLE '' DATABASE currentDatabase()))
+LAYOUT(COMPLEX_KEY_DIRECT());
+
+SELECT 'complex key';
+
+SELECT name, key FROM system.dictionaries WHERE name='example_complex_key_dictionary' AND database=currentDatabase();

tests/testflows/map_type/configs/clickhouse/config.d/logs.xml

@@ -0,0 +1,16 @@
+<yandex>
+    <logger>
+        <level>trace</level>
+        <log>/var/log/clickhouse-server/log.log</log>
+        <errorlog>/var/log/clickhouse-server/log.err.log</errorlog>
+        <size>1000M</size>
+        <count>10</count>
+        <stderr>/var/log/clickhouse-server/stderr.log</stderr>
+        <stdout>/var/log/clickhouse-server/stdout.log</stdout>
+    </logger>
+    <part_log>
+        <database>system</database>
+        <table>part_log</table>
+        <flush_interval_milliseconds>500</flush_interval_milliseconds>
+    </part_log>
+</yandex>

tests/testflows/map_type/configs/clickhouse/config.d/remote.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0"?>
+<yandex>
+    <remote_servers>
+        <replicated_cluster>
+            <shard>
+                <internal_replication>true</internal_replication>
+                <replica>
+                    <host>clickhouse1</host>
+                    <port>9000</port>
+                </replica>
+                <replica>
+                    <host>clickhouse2</host>
+                    <port>9000</port>
+                </replica>
+                <replica>
+                    <host>clickhouse3</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+        </replicated_cluster>
+        <sharded_cluster>
+            <shard>
+                <replica>
+                    <host>clickhouse1</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+            <shard>
+                <replica>
+                    <host>clickhouse2</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+            <shard>
+                <replica>
+                    <host>clickhouse3</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+        </sharded_cluster>
+    </remote_servers>
+</yandex>

tests/testflows/map_type/configs/clickhouse/config.d/zookeeper.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<yandex>
+    <zookeeper>
+	    <node index="1">
+		    <host>zookeeper</host>
+		    <port>2181</port>
+	    </node>
+        <session_timeout_ms>15000</session_timeout_ms>
+    </zookeeper>
+</yandex>

tests/testflows/map_type/configs/clickhouse/config.xml

@@ -0,0 +1,448 @@
+<?xml version="1.0"?>
+<!--
+  NOTE: User and query level settings are set up in "users.xml" file.
+-->
+<yandex>
+    <logger>
+        <!-- Possible levels: https://github.com/pocoproject/poco/blob/develop/Foundation/include/Poco/Logger.h#L105 -->
+        <level>trace</level>
+        <log>/var/log/clickhouse-server/clickhouse-server.log</log>
+        <errorlog>/var/log/clickhouse-server/clickhouse-server.err.log</errorlog>
+        <size>1000M</size>
+        <count>10</count>
+        <!-- <console>1</console> --> <!-- Default behavior is autodetection (log to console if not daemon mode and is tty) -->
+    </logger>
+    <!--display_name>production</display_name--> <!-- It is the name that will be shown in the client -->
+    <http_port>8123</http_port>
+    <tcp_port>9000</tcp_port>
+
+    <!-- For HTTPS and SSL over native protocol. -->
+    <!--
+    <https_port>8443</https_port>
+    <tcp_port_secure>9440</tcp_port_secure>
+    -->
+
+    <!-- Used with https_port and tcp_port_secure. Full ssl options list: https://github.com/ClickHouse-Extras/poco/blob/master/NetSSL_OpenSSL/include/Poco/Net/SSLManager.h#L71 -->
+    <openSSL>
+        <server> <!-- Used for https server AND secure tcp port -->
+            <!-- openssl req -subj "/CN=localhost" -new -newkey rsa:2048 -days 365 -nodes -x509 -keyout /etc/clickhouse-server/server.key -out /etc/clickhouse-server/server.crt -->
+            <certificateFile>/etc/clickhouse-server/server.crt</certificateFile>
+            <privateKeyFile>/etc/clickhouse-server/server.key</privateKeyFile>
+            <!-- openssl dhparam -out /etc/clickhouse-server/dhparam.pem 4096 -->
+            <dhParamsFile>/etc/clickhouse-server/dhparam.pem</dhParamsFile>
+            <verificationMode>none</verificationMode>
+            <loadDefaultCAFile>true</loadDefaultCAFile>
+            <cacheSessions>true</cacheSessions>
+            <disableProtocols>sslv2,sslv3</disableProtocols>
+            <preferServerCiphers>true</preferServerCiphers>
+        </server>
+
+        <client> <!-- Used for connecting to https dictionary source -->
+            <loadDefaultCAFile>true</loadDefaultCAFile>
+            <cacheSessions>true</cacheSessions>
+            <disableProtocols>sslv2,sslv3</disableProtocols>
+            <preferServerCiphers>true</preferServerCiphers>
+            <!-- Use for self-signed: <verificationMode>none</verificationMode> -->
+            <invalidCertificateHandler>
+                <!-- Use for self-signed: <name>AcceptCertificateHandler</name> -->
+                <name>RejectCertificateHandler</name>
+            </invalidCertificateHandler>
+        </client>
+    </openSSL>
+
+    <!-- Default root page on http[s] server. For example load UI from https://tabix.io/ when opening http://localhost:8123 -->
+    <!--
+    <http_server_default_response><![CDATA[<html ng-app="SMI2"><head><base href="http://ui.tabix.io/"></head><body><div ui-view="" class="content-ui"></div><script src="http://loader.tabix.io/master.js"></script></body></html>]]></http_server_default_response>
+    -->
+
+    <!-- Port for communication between replicas. Used for data exchange. -->
+    <interserver_http_port>9009</interserver_http_port>
+
+    <!-- Hostname that is used by other replicas to request this server.
+         If not specified, than it is determined analoguous to 'hostname -f' command.
+         This setting could be used to switch replication to another network interface.
+      -->
+    <!--
+    <interserver_http_host>example.yandex.ru</interserver_http_host>
+    -->
+
+    <!-- Listen specified host. use :: (wildcard IPv6 address), if you want to accept connections both with IPv4 and IPv6 from everywhere. -->
+    <!-- <listen_host>::</listen_host> -->
+    <!-- Same for hosts with disabled ipv6: -->
+    <listen_host>0.0.0.0</listen_host>
+
+    <!-- Default values - try listen localhost on ipv4 and ipv6: -->
+    <!--
+    <listen_host>::1</listen_host>
+    <listen_host>127.0.0.1</listen_host>
+    -->
+    <!-- Don't exit if ipv6 or ipv4 unavailable, but listen_host with this protocol specified -->
+    <!-- <listen_try>0</listen_try> -->
+
+    <!-- Allow listen on same address:port -->
+    <!-- <listen_reuse_port>0</listen_reuse_port> -->
+
+    <!-- <listen_backlog>64</listen_backlog> -->
+
+    <max_connections>4096</max_connections>
+    <keep_alive_timeout>3</keep_alive_timeout>
+
+    <!-- Maximum number of concurrent queries. -->
+    <max_concurrent_queries>100</max_concurrent_queries>
+
+    <!-- Set limit on number of open files (default: maximum). This setting makes sense on Mac OS X because getrlimit() fails to retrieve
+         correct maximum value. -->
+    <!-- <max_open_files>262144</max_open_files> -->
+
+    <!-- Size of cache of uncompressed blocks of data, used in tables of MergeTree family.
+         In bytes. Cache is single for server. Memory is allocated only on demand.
+         Cache is used when 'use_uncompressed_cache' user setting turned on (off by default).
+         Uncompressed cache is advantageous only for very short queries and in rare cases.
+      -->
+    <uncompressed_cache_size>8589934592</uncompressed_cache_size>
+
+    <!-- Approximate size of mark cache, used in tables of MergeTree family.
+         In bytes. Cache is single for server. Memory is allocated only on demand.
+         You should not lower this value.
+      -->
+    <mark_cache_size>5368709120</mark_cache_size>
+
+
+    <!-- Path to data directory, with trailing slash. -->
+    <path>/var/lib/clickhouse/</path>
+
+    <!-- Path to temporary data for processing hard queries. -->
+    <tmp_path>/var/lib/clickhouse/tmp/</tmp_path>
+
+    <!-- Directory with user provided files that are accessible by 'file' table function. -->
+    <user_files_path>/var/lib/clickhouse/user_files/</user_files_path>
+
+    <!-- Path to folder where users and roles created by SQL commands are stored. -->
+    <access_control_path>/var/lib/clickhouse/access/</access_control_path>
+
+    <!-- Sources to read users, roles, access rights, profiles of settings, quotas. -->
+    <user_directories>
+        <users_xml>
+            <!-- Path to configuration file with predefined users. -->
+            <path>users.xml</path>
+        </users_xml>
+        <local_directory>
+            <!-- Path to folder where users created by SQL commands are stored. -->
+            <path>/var/lib/clickhouse/access/</path>
+        </local_directory>
+    </user_directories>
+
+    <!-- Path to configuration file with users, access rights, profiles of settings, quotas. -->
+    <users_config>users.xml</users_config>
+
+    <!-- Default profile of settings. -->
+    <default_profile>default</default_profile>
+
+    <!-- System profile of settings. This settings are used by internal processes (Buffer storage, Distibuted DDL worker and so on). -->
+    <!-- <system_profile>default</system_profile> -->
+
+    <!-- Default database. -->
+    <default_database>default</default_database>
+
+    <!-- Server time zone could be set here.
+
+         Time zone is used when converting between String and DateTime types,
+          when printing DateTime in text formats and parsing DateTime from text,
+          it is used in date and time related functions, if specific time zone was not passed as an argument.
+
+         Time zone is specified as identifier from IANA time zone database, like UTC or Africa/Abidjan.
+         If not specified, system time zone at server startup is used.
+
+         Please note, that server could display time zone alias instead of specified name.
+         Example: W-SU is an alias for Europe/Moscow and Zulu is an alias for UTC.
+    -->
+    <!-- <timezone>Europe/Moscow</timezone> -->
+
+    <!-- You can specify umask here (see "man umask"). Server will apply it on startup.
+         Number is always parsed as octal. Default umask is 027 (other users cannot read logs, data files, etc; group can only read).
+    -->
+    <!-- <umask>022</umask> -->
+
+    <!-- Perform mlockall after startup to lower first queries latency
+          and to prevent clickhouse executable from being paged out under high IO load.
+         Enabling this option is recommended but will lead to increased startup time for up to a few seconds.
+    -->
+    <mlock_executable>false</mlock_executable>
+
+    <!-- Configuration of clusters that could be used in Distributed tables.
+         https://clickhouse.yandex/docs/en/table_engines/distributed/
+      -->
+    <remote_servers incl="clickhouse_remote_servers" >
+        <!-- Test only shard config for testing distributed storage -->
+        <test_shard_localhost>
+            <shard>
+                <replica>
+                    <host>localhost</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+        </test_shard_localhost>
+        <test_cluster_two_shards_localhost>
+             <shard>
+                 <replica>
+                     <host>localhost</host>
+                     <port>9000</port>
+                 </replica>
+             </shard>
+             <shard>
+                 <replica>
+                     <host>localhost</host>
+                     <port>9000</port>
+                 </replica>
+             </shard>
+         </test_cluster_two_shards_localhost>
+        <test_shard_localhost_secure>
+            <shard>
+                <replica>
+                    <host>localhost</host>
+                    <port>9440</port>
+                    <secure>1</secure>
+                </replica>
+            </shard>
+        </test_shard_localhost_secure>
+        <test_unavailable_shard>
+            <shard>
+                <replica>
+                    <host>localhost</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+            <shard>
+                <replica>
+                    <host>localhost</host>
+                    <port>1</port>
+                </replica>
+            </shard>
+        </test_unavailable_shard>
+    </remote_servers>
+
+
+    <!-- If element has 'incl' attribute, then for it's value will be used corresponding substitution from another file.
+         By default, path to file with substitutions is /etc/metrika.xml. It could be changed in config in 'include_from' element.
+         Values for substitutions are specified in /yandex/name_of_substitution elements in that file.
+      -->
+
+    <!-- ZooKeeper is used to store metadata about replicas, when using Replicated tables.
+         Optional. If you don't use replicated tables, you could omit that.
+
+         See https://clickhouse.yandex/docs/en/table_engines/replication/
+      -->
+    <zookeeper incl="zookeeper-servers" optional="true" />
+
+    <!-- Substitutions for parameters of replicated tables.
+          Optional. If you don't use replicated tables, you could omit that.
+
+         See https://clickhouse.yandex/docs/en/table_engines/replication/#creating-replicated-tables
+      -->
+    <macros incl="macros" optional="true" />
+
+
+    <!-- Reloading interval for embedded dictionaries, in seconds. Default: 3600. -->
+    <builtin_dictionaries_reload_interval>3600</builtin_dictionaries_reload_interval>
+
+
+    <!-- Maximum session timeout, in seconds. Default: 3600. -->
+    <max_session_timeout>3600</max_session_timeout>
+
+    <!-- Default session timeout, in seconds. Default: 60. -->
+    <default_session_timeout>60</default_session_timeout>
+
+    <!-- Sending data to Graphite for monitoring. Several sections can be defined. -->
+    <!--
+        interval - send every X second
+        root_path - prefix for keys
+        hostname_in_path - append hostname to root_path (default = true)
+        metrics - send data from table system.metrics
+        events - send data from table system.events
+        asynchronous_metrics - send data from table system.asynchronous_metrics
+    -->
+    <!--
+    <graphite>
+        <host>localhost</host>
+        <port>42000</port>
+        <timeout>0.1</timeout>
+        <interval>60</interval>
+        <root_path>one_min</root_path>
+        <hostname_in_path>true</hostname_in_path>
+
+        <metrics>true</metrics>
+        <events>true</events>
+        <asynchronous_metrics>true</asynchronous_metrics>
+    </graphite>
+    <graphite>
+        <host>localhost</host>
+        <port>42000</port>
+        <timeout>0.1</timeout>
+        <interval>1</interval>
+        <root_path>one_sec</root_path>
+
+        <metrics>true</metrics>
+        <events>true</events>
+        <asynchronous_metrics>false</asynchronous_metrics>
+    </graphite>
+    -->
+
+
+    <!-- Query log. Used only for queries with setting log_queries = 1. -->
+    <query_log>
+        <!-- What table to insert data. If table is not exist, it will be created.
+             When query log structure is changed after system update,
+              then old table will be renamed and new table will be created automatically.
+        -->
+        <database>system</database>
+        <table>query_log</table>
+        <!--
+            PARTITION BY expr https://clickhouse.yandex/docs/en/table_engines/custom_partitioning_key/
+            Example:
+                event_date
+                toMonday(event_date)
+                toYYYYMM(event_date)
+                toStartOfHour(event_time)
+        -->
+        <partition_by>toYYYYMM(event_date)</partition_by>
+        <!-- Interval of flushing data. -->
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+    </query_log>
+
+    <!-- Trace log. Stores stack traces collected by query profilers.
+         See query_profiler_real_time_period_ns and query_profiler_cpu_time_period_ns settings. -->
+    <trace_log>
+        <database>system</database>
+        <table>trace_log</table>
+
+        <partition_by>toYYYYMM(event_date)</partition_by>
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+    </trace_log>
+
+    <!-- Query thread log. Has information about all threads participated in query execution.
+         Used only for queries with setting log_query_threads = 1. -->
+    <query_thread_log>
+        <database>system</database>
+        <table>query_thread_log</table>
+        <partition_by>toYYYYMM(event_date)</partition_by>
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+    </query_thread_log>
+
+    <!-- Uncomment if use part log.
+         Part log contains information about all actions with parts in MergeTree tables (creation, deletion, merges, downloads).
+    <part_log>
+        <database>system</database>
+        <table>part_log</table>
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+    </part_log>
+    -->
+
+    <!-- Uncomment to write text log into table.
+         Text log contains all information from usual server log but stores it in structured and efficient way.
+    <text_log>
+        <database>system</database>
+        <table>text_log</table>
+        <flush_interval_milliseconds>7500</flush_interval_milliseconds>
+    </text_log>
+    -->
+
+    <!-- Parameters for embedded dictionaries, used in Yandex.Metrica.
+         See https://clickhouse.yandex/docs/en/dicts/internal_dicts/
+    -->
+
+    <!-- Path to file with region hierarchy. -->
+    <!-- <path_to_regions_hierarchy_file>/opt/geo/regions_hierarchy.txt</path_to_regions_hierarchy_file> -->
+
+    <!-- Path to directory with files containing names of regions -->
+    <!-- <path_to_regions_names_files>/opt/geo/</path_to_regions_names_files> -->
+
+
+    <!-- Configuration of external dictionaries. See:
+         https://clickhouse.yandex/docs/en/dicts/external_dicts/
+    -->
+    <dictionaries_config>*_dictionary.xml</dictionaries_config>
+
+    <!-- Uncomment if you want data to be compressed 30-100% better.
+         Don't do that if you just started using ClickHouse.
+      -->
+    <compression incl="clickhouse_compression">
+    <!--
+        <!- - Set of variants. Checked in order. Last matching case wins. If nothing matches, lz4 will be used. - ->
+        <case>
+
+            <!- - Conditions. All must be satisfied. Some conditions may be omitted. - ->
+            <min_part_size>10000000000</min_part_size>        <!- - Min part size in bytes. - ->
+            <min_part_size_ratio>0.01</min_part_size_ratio>   <!- - Min size of part relative to whole table size. - ->
+
+            <!- - What compression method to use. - ->
+            <method>zstd</method>
+        </case>
+    -->
+    </compression>
+
+    <!-- Allow to execute distributed DDL queries (CREATE, DROP, ALTER, RENAME) on cluster.
+         Works only if ZooKeeper is enabled. Comment it if such functionality isn't required. -->
+    <distributed_ddl>
+        <!-- Path in ZooKeeper to queue with DDL queries -->
+        <path>/clickhouse/task_queue/ddl</path>
+
+        <!-- Settings from this profile will be used to execute DDL queries -->
+        <!-- <profile>default</profile> -->
+    </distributed_ddl>
+
+    <!-- Settings to fine tune MergeTree tables. See documentation in source code, in MergeTreeSettings.h -->
+    <!--
+    <merge_tree>
+        <max_suspicious_broken_parts>5</max_suspicious_broken_parts>
+    </merge_tree>
+    -->
+
+    <!-- Protection from accidental DROP.
+         If size of a MergeTree table is greater than max_table_size_to_drop (in bytes) than table could not be dropped with any DROP query.
+         If you want do delete one table and don't want to restart clickhouse-server, you could create special file <clickhouse-path>/flags/force_drop_table and make DROP once.
+         By default max_table_size_to_drop is 50GB; max_table_size_to_drop=0 allows to DROP any tables.
+         The same for max_partition_size_to_drop.
+         Uncomment to disable protection.
+    -->
+    <!-- <max_table_size_to_drop>0</max_table_size_to_drop> -->
+    <!-- <max_partition_size_to_drop>0</max_partition_size_to_drop> -->
+
+    <!-- Example of parameters for GraphiteMergeTree table engine -->
+    <graphite_rollup_example>
+        <pattern>
+            <regexp>click_cost</regexp>
+            <function>any</function>
+            <retention>
+                <age>0</age>
+                <precision>3600</precision>
+            </retention>
+            <retention>
+                <age>86400</age>
+                <precision>60</precision>
+            </retention>
+        </pattern>
+        <default>
+            <function>max</function>
+            <retention>
+                <age>0</age>
+                <precision>60</precision>
+            </retention>
+            <retention>
+                <age>3600</age>
+                <precision>300</precision>
+            </retention>
+            <retention>
+                <age>86400</age>
+                <precision>3600</precision>
+            </retention>
+        </default>
+    </graphite_rollup_example>
+
+    <!-- Directory in <clickhouse-path> containing schema files for various input formats.
+         The directory will be created if it doesn't exist.
+      -->
+    <format_schema_path>/var/lib/clickhouse/format_schemas/</format_schema_path>
+
+    <!-- Uncomment to disable ClickHouse internal DNS caching. -->
+    <!-- <disable_internal_dns_cache>1</disable_internal_dns_cache> -->
+</yandex>

tests/testflows/map_type/configs/clickhouse/users.xml

@@ -0,0 +1,133 @@
+<?xml version="1.0"?>
+<yandex>
+    <!-- Profiles of settings. -->
+    <profiles>
+        <!-- Default settings. -->
+        <default>
+            <!-- Maximum memory usage for processing single query, in bytes. -->
+            <max_memory_usage>10000000000</max_memory_usage>
+
+            <!-- Use cache of uncompressed blocks of data. Meaningful only for processing many of very short queries. -->
+            <use_uncompressed_cache>0</use_uncompressed_cache>
+
+            <!-- How to choose between replicas during distributed query processing.
+                 random - choose random replica from set of replicas with minimum number of errors
+                 nearest_hostname - from set of replicas with minimum number of errors, choose replica
+                  with minimum number of different symbols between replica's hostname and local hostname
+                  (Hamming distance).
+                 in_order - first live replica is chosen in specified order.
+                 first_or_random - if first replica one has higher number of errors, pick a random one from replicas with minimum number of errors.
+            -->
+            <load_balancing>random</load_balancing>
+        </default>
+
+        <!-- Profile that allows only read queries. -->
+        <readonly>
+            <readonly>1</readonly>
+        </readonly>
+    </profiles>
+
+    <!-- Users and ACL. -->
+    <users>
+        <!-- If user name was not specified, 'default' user is used. -->
+        <default>
+            <!-- Password could be specified in plaintext or in SHA256 (in hex format).
+
+                 If you want to specify password in plaintext (not recommended), place it in 'password' element.
+                 Example: <password>qwerty</password>.
+                 Password could be empty.
+
+                 If you want to specify SHA256, place it in 'password_sha256_hex' element.
+                 Example: <password_sha256_hex>65e84be33532fb784c48129675f9eff3a682b27168c0ea744b2cf58ee02337c5</password_sha256_hex>
+                 Restrictions of SHA256: impossibility to connect to ClickHouse using MySQL JS client (as of July 2019).
+
+                 If you want to specify double SHA1, place it in 'password_double_sha1_hex' element.
+                 Example: <password_double_sha1_hex>e395796d6546b1b65db9d665cd43f0e858dd4303</password_double_sha1_hex>
+
+                 How to generate decent password:
+                 Execute: PASSWORD=$(base64 < /dev/urandom | head -c8); echo "$PASSWORD"; echo -n "$PASSWORD" | sha256sum | tr -d '-'
+                 In first line will be password and in second - corresponding SHA256.
+
+                 How to generate double SHA1:
+                 Execute: PASSWORD=$(base64 < /dev/urandom | head -c8); echo "$PASSWORD"; echo -n "$PASSWORD" | openssl dgst -sha1 -binary | openssl dgst -sha1
+                 In first line will be password and in second - corresponding double SHA1.
+            -->
+            <password></password>
+
+            <!-- List of networks with open access.
+
+                 To open access from everywhere, specify:
+                    <ip>::/0</ip>
+
+                 To open access only from localhost, specify:
+                    <ip>::1</ip>
+                    <ip>127.0.0.1</ip>
+
+                 Each element of list has one of the following forms:
+                 <ip> IP-address or network mask. Examples: 213.180.204.3 or 10.0.0.1/8 or 10.0.0.1/255.255.255.0
+                     2a02:6b8::3 or 2a02:6b8::3/64 or 2a02:6b8::3/ffff:ffff:ffff:ffff::.
+                 <host> Hostname. Example: server01.yandex.ru.
+                     To check access, DNS query is performed, and all received addresses compared to peer address.
+                 <host_regexp> Regular expression for host names. Example, ^server\d\d-\d\d-\d\.yandex\.ru$
+                     To check access, DNS PTR query is performed for peer address and then regexp is applied.
+                     Then, for result of PTR query, another DNS query is performed and all received addresses compared to peer address.
+                     Strongly recommended that regexp is ends with $
+                 All results of DNS requests are cached till server restart.
+            -->
+            <networks incl="networks" replace="replace">
+                <ip>::/0</ip>
+            </networks>
+
+            <!-- Settings profile for user. -->
+            <profile>default</profile>
+
+            <!-- Quota for user. -->
+            <quota>default</quota>
+
+            <!-- Allow access management -->
+            <access_management>1</access_management>
+
+            <!-- Example of row level security policy. -->
+            <!-- <databases>
+                <test>
+                    <filtered_table1>
+                        <filter>a = 1</filter>
+                    </filtered_table1>
+                    <filtered_table2>
+                        <filter>a + b &lt; 1 or c - d &gt; 5</filter>
+                    </filtered_table2>
+                </test>
+            </databases> -->
+        </default>
+
+        <!-- Example of user with readonly access. -->
+        <!-- <readonly>
+            <password></password>
+            <networks incl="networks" replace="replace">
+                <ip>::1</ip>
+                <ip>127.0.0.1</ip>
+            </networks>
+            <profile>readonly</profile>
+            <quota>default</quota>
+        </readonly> -->
+    </users>
+
+    <!-- Quotas. -->
+    <quotas>
+        <!-- Name of quota. -->
+        <default>
+            <!-- Limits for time interval. You could specify many intervals with different limits. -->
+            <interval>
+                <!-- Length of interval. -->
+                <duration>3600</duration>
+
+                <!-- No limits. Just calculate resource usage for time interval. -->
+                <queries>0</queries>
+                <errors>0</errors>
+                <result_rows>0</result_rows>
+                <read_rows>0</read_rows>
+                <execution_time>0</execution_time>
+            </interval>
+        </default>
+    </quotas>
+</yandex>

tests/testflows/map_type/configs/clickhouse1/config.d/macros.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0"?>
+<yandex>
+    <macros>
+        <replica>clickhouse1</replica>
+        <shard>01</shard>
+        <shard2>01</shard2>
+    </macros>
+</yandex>

tests/testflows/map_type/configs/clickhouse2/config.d/macros.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0"?>
+<yandex>
+    <macros>
+        <replica>clickhouse2</replica>
+        <shard>01</shard>
+        <shard2>02</shard2>
+    </macros>
+</yandex>

tests/testflows/map_type/configs/clickhouse3/config.d/macros.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0"?>
+<yandex>
+    <macros>
+        <replica>clickhouse3</replica>
+        <shard>01</shard>
+        <shard2>03</shard2>
+    </macros>
+</yandex>

tests/testflows/map_type/docker-compose/clickhouse-service.yml

@@ -0,0 +1,27 @@
+version: '2.3'
+
+services:
+  clickhouse:
+    image: yandex/clickhouse-integration-test
+    expose:
+      - "9000"
+      - "9009"
+      - "8123"
+    volumes:
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse/config.d:/etc/clickhouse-server/config.d"
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse/users.d:/etc/clickhouse-server/users.d"
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse/config.xml:/etc/clickhouse-server/config.xml"
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse/users.xml:/etc/clickhouse-server/users.xml"
+      - "${CLICKHOUSE_TESTS_SERVER_BIN_PATH:-/usr/bin/clickhouse}:/usr/bin/clickhouse"
+      - "${CLICKHOUSE_TESTS_ODBC_BRIDGE_BIN_PATH:-/usr/bin/clickhouse-odbc-bridge}:/usr/bin/clickhouse-odbc-bridge"
+    entrypoint: bash -c "clickhouse server --config-file=/etc/clickhouse-server/config.xml --log-file=/var/log/clickhouse-server/clickhouse-server.log --errorlog-file=/var/log/clickhouse-server/clickhouse-server.err.log"
+    healthcheck:
+      test: clickhouse client --query='select 1'
+      interval: 10s
+      timeout: 10s
+      retries: 3
+      start_period: 300s
+    cap_add:
+      - SYS_PTRACE
+    security_opt:
+      - label:disable

tests/testflows/map_type/docker-compose/docker-compose.yml

@@ -0,0 +1,60 @@
+version: '2.3'
+
+services:
+  zookeeper:
+    extends:
+      file: zookeeper-service.yml
+      service: zookeeper
+
+  clickhouse1:
+    extends:
+      file: clickhouse-service.yml
+      service: clickhouse
+    hostname: clickhouse1
+    volumes:
+      - "${CLICKHOUSE_TESTS_DIR}/_instances/clickhouse1/database/:/var/lib/clickhouse/"
+      - "${CLICKHOUSE_TESTS_DIR}/_instances/clickhouse1/logs/:/var/log/clickhouse-server/"
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse1/config.d/macros.xml:/etc/clickhouse-server/config.d/macros.xml"
+    depends_on:
+      zookeeper:
+        condition: service_healthy
+
+  clickhouse2:
+    extends:
+      file: clickhouse-service.yml
+      service: clickhouse
+    hostname: clickhouse2
+    volumes:
+      - "${CLICKHOUSE_TESTS_DIR}/_instances/clickhouse2/database/:/var/lib/clickhouse/"
+      - "${CLICKHOUSE_TESTS_DIR}/_instances/clickhouse2/logs/:/var/log/clickhouse-server/"
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse2/config.d/macros.xml:/etc/clickhouse-server/config.d/macros.xml"
+    depends_on:
+      zookeeper:
+        condition: service_healthy
+
+  clickhouse3:
+    extends:
+      file: clickhouse-service.yml
+      service: clickhouse
+    hostname: clickhouse3
+    volumes:
+      - "${CLICKHOUSE_TESTS_DIR}/_instances/clickhouse3/database/:/var/lib/clickhouse/"
+      - "${CLICKHOUSE_TESTS_DIR}/_instances/clickhouse3/logs/:/var/log/clickhouse-server/"
+      - "${CLICKHOUSE_TESTS_DIR}/configs/clickhouse3/config.d/macros.xml:/etc/clickhouse-server/config.d/macros.xml"
+    depends_on:
+      zookeeper:
+        condition: service_healthy
+
+  # dummy service which does nothing, but allows to postpone
+  # 'docker-compose up -d' till all dependecies will go healthy
+  all_services_ready:
+    image: hello-world
+    depends_on:
+      clickhouse1:
+        condition: service_healthy
+      clickhouse2:
+        condition: service_healthy
+      clickhouse3:
+        condition: service_healthy
+      zookeeper:
+        condition: service_healthy

tests/testflows/map_type/docker-compose/zookeeper-service.yml

@@ -0,0 +1,18 @@
+version: '2.3'
+
+services:
+  zookeeper:
+    image: zookeeper:3.4.12
+    expose:
+      - "2181"
+    environment:
+      ZOO_TICK_TIME: 500
+      ZOO_MY_ID: 1
+    healthcheck:
+      test: echo stat | nc localhost 2181
+      interval: 3s
+      timeout: 2s
+      retries: 5
+      start_period: 2s
+    security_opt:
+      - label:disable

tests/testflows/map_type/regression.py

@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+import sys
+
+from testflows.core import *
+
+append_path(sys.path, "..")
+
+from helpers.cluster import Cluster
+from helpers.argparser import argparser
+from map_type.requirements import SRS018_ClickHouse_Map_Data_Type 
+
+xfails = {
+    "tests/table map with key integer/Int:":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21032")],
+    "tests/table map with value integer/Int:":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21032")],
+    "tests/table map with key integer/UInt256":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21031")],
+    "tests/table map with value integer/UInt256":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21031")],
+    "tests/select map with key integer/Int64":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21030")],
+    "tests/select map with value integer/Int64":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21030")],
+    "tests/cast tuple of two arrays to map/string -> int":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21029")],
+    "tests/mapcontains/null key in map":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21028")],
+    "tests/mapcontains/null key not in map":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21028")],
+    "tests/mapkeys/null key not in map":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21028")],
+    "tests/mapkeys/null key in map":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21028")],
+    "tests/mapcontains/select nullable key":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21026")],
+    "tests/mapkeys/select keys from column":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21026")],
+    "tests/table map select key with value string/LowCardinality:":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21406")],
+    "tests/table map select key with key string/FixedString":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21406")],
+    "tests/table map select key with key string/Nullable":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21406")],
+    "tests/table map select key with key string/Nullable(NULL)":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21026")],
+    "tests/table map select key with key string/LowCardinality:":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21406")],
+    "tests/table map select key with key integer/Int:":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21032")],
+    "tests/table map select key with key integer/UInt256":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21031")],
+    "tests/table map select key with key integer/toNullable":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21406")],
+    "tests/table map select key with key integer/toNullable(NULL)":
+        [(Fail, "https://github.com/ClickHouse/ClickHouse/issues/21026")],
+    "tests/select map with key integer/Int128":
+        [(Fail, "large Int128 as key not supported")],
+    "tests/select map with key integer/Int256":
+        [(Fail, "large Int256 as key not supported")],
+    "tests/select map with key integer/UInt256":
+        [(Fail, "large UInt256 as key not supported")],
+    "tests/select map with key integer/toNullable":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/select map with key integer/toNullable(NULL)":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/select map with key string/Nullable":
+        [(Fail, "Nullable type as key not supported")],   
+    "tests/select map with key string/Nullable(NULL)":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/table map queries/select map with nullable value":
+        [(Fail, "Nullable value not supported")],
+    "tests/table map with key integer/toNullable":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/table map with key integer/toNullable(NULL)":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/table map with key string/Nullable":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/table map with key string/Nullable(NULL)":
+        [(Fail, "Nullable type as key not supported")],
+    "tests/table map with key string/LowCardinality(String)":
+        [(Fail, "LowCardinality(String) as key not supported")],
+    "tests/table map with key string/LowCardinality(String) cast from String":
+        [(Fail, "LowCardinality(String) as key not supported")],
+    "tests/table map with key string/LowCardinality(String) for key and value":
+        [(Fail, "LowCardinality(String) as key not supported")],
+    "tests/table map with key string/LowCardinality(FixedString)":
+        [(Fail, "LowCardinality(FixedString) as key not supported")],
+    "tests/table map with value string/LowCardinality(String) for key and value":
+        [(Fail, "LowCardinality(String) as key not supported")],
+}
+
+xflags = {
+}
+
+@TestModule
+@ArgumentParser(argparser)
+@XFails(xfails)
+@XFlags(xflags)
+@Name("map type")
+@Specifications(
+    SRS018_ClickHouse_Map_Data_Type
+)
+def regression(self, local, clickhouse_binary_path, stress=None, parallel=None):
+    """Map type regression.
+    """
+    nodes = {
+        "clickhouse":
+            ("clickhouse1", "clickhouse2", "clickhouse3")
+    }
+    with Cluster(local, clickhouse_binary_path, nodes=nodes) as cluster:
+        self.context.cluster = cluster
+        self.context.stress = stress
+
+        if parallel is not None:
+            self.context.parallel = parallel
+
+        Feature(run=load("map_type.tests.feature", "feature"))
+
+if main():
+    regression()

tests/testflows/map_type/requirements/__init__.py

@@ -0,0 +1 @@
+from .requirements import *

tests/testflows/map_type/requirements/requirements.md

@@ -0,0 +1,512 @@
+# SRS018 ClickHouse Map Data Type
+# Software Requirements Specification
+
+## Table of Contents
+
+* 1 [Revision History](#revision-history)
+* 2 [Introduction](#introduction)
+* 3 [Requirements](#requirements)
+  * 3.1 [General](#general)
+    * 3.1.1 [RQ.SRS-018.ClickHouse.Map.DataType](#rqsrs-018clickhousemapdatatype)
+  * 3.2 [Performance](#performance)
+    * 3.2.1 [RQ.SRS-018.ClickHouse.Map.DataType.Performance.Vs.ArrayOfTuples](#rqsrs-018clickhousemapdatatypeperformancevsarrayoftuples)
+    * 3.2.2 [RQ.SRS-018.ClickHouse.Map.DataType.Performance.Vs.TupleOfArrays](#rqsrs-018clickhousemapdatatypeperformancevstupleofarrays)
+  * 3.3 [Key Types](#key-types)
+    * 3.3.1 [RQ.SRS-018.ClickHouse.Map.DataType.Key.String](#rqsrs-018clickhousemapdatatypekeystring)
+    * 3.3.2 [RQ.SRS-018.ClickHouse.Map.DataType.Key.Integer](#rqsrs-018clickhousemapdatatypekeyinteger)
+  * 3.4 [Value Types](#value-types)
+    * 3.4.1 [RQ.SRS-018.ClickHouse.Map.DataType.Value.String](#rqsrs-018clickhousemapdatatypevaluestring)
+    * 3.4.2 [RQ.SRS-018.ClickHouse.Map.DataType.Value.Integer](#rqsrs-018clickhousemapdatatypevalueinteger)
+    * 3.4.3 [RQ.SRS-018.ClickHouse.Map.DataType.Value.Array](#rqsrs-018clickhousemapdatatypevaluearray)
+  * 3.5 [Invalid Types](#invalid-types)
+    * 3.5.1 [RQ.SRS-018.ClickHouse.Map.DataType.Invalid.Nullable](#rqsrs-018clickhousemapdatatypeinvalidnullable)
+    * 3.5.2 [RQ.SRS-018.ClickHouse.Map.DataType.Invalid.NothingNothing](#rqsrs-018clickhousemapdatatypeinvalidnothingnothing)
+  * 3.6 [Duplicated Keys](#duplicated-keys)
+    * 3.6.1 [RQ.SRS-018.ClickHouse.Map.DataType.DuplicatedKeys](#rqsrs-018clickhousemapdatatypeduplicatedkeys)
+  * 3.7 [Array of Maps](#array-of-maps)
+    * 3.7.1 [RQ.SRS-018.ClickHouse.Map.DataType.ArrayOfMaps](#rqsrs-018clickhousemapdatatypearrayofmaps)
+  * 3.8 [Nested With Maps](#nested-with-maps)
+    * 3.8.1 [RQ.SRS-018.ClickHouse.Map.DataType.NestedWithMaps](#rqsrs-018clickhousemapdatatypenestedwithmaps)
+  * 3.9 [Value Retrieval](#value-retrieval)
+    * 3.9.1 [RQ.SRS-018.ClickHouse.Map.DataType.Value.Retrieval](#rqsrs-018clickhousemapdatatypevalueretrieval)
+    * 3.9.2 [RQ.SRS-018.ClickHouse.Map.DataType.Value.Retrieval.KeyInvalid](#rqsrs-018clickhousemapdatatypevalueretrievalkeyinvalid)
+    * 3.9.3 [RQ.SRS-018.ClickHouse.Map.DataType.Value.Retrieval.KeyNotFound](#rqsrs-018clickhousemapdatatypevalueretrievalkeynotfound)
+  * 3.10 [Converting Tuple(Array, Array) to Map](#converting-tuplearray-array-to-map)
+    * 3.10.1 [RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.TupleOfArraysToMap](#rqsrs-018clickhousemapdatatypeconversionfromtupleofarraystomap)
+    * 3.10.2 [RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.TupleOfArraysMap.Invalid](#rqsrs-018clickhousemapdatatypeconversionfromtupleofarraysmapinvalid)
+  * 3.11 [Converting Array(Tuple(K,V)) to Map](#converting-arraytuplekv-to-map)
+    * 3.11.1 [RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.ArrayOfTuplesToMap](#rqsrs-018clickhousemapdatatypeconversionfromarrayoftuplestomap)
+    * 3.11.2 [RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.ArrayOfTuplesToMap.Invalid](#rqsrs-018clickhousemapdatatypeconversionfromarrayoftuplestomapinvalid)
+  * 3.12 [Keys and Values Subcolumns](#keys-and-values-subcolumns)
+    * 3.12.1 [RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Keys](#rqsrs-018clickhousemapdatatypesubcolumnskeys)
+    * 3.12.2 [RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Keys.ArrayFunctions](#rqsrs-018clickhousemapdatatypesubcolumnskeysarrayfunctions)
+    * 3.12.3 [RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Keys.InlineDefinedMap](#rqsrs-018clickhousemapdatatypesubcolumnskeysinlinedefinedmap)
+    * 3.12.4 [RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Values](#rqsrs-018clickhousemapdatatypesubcolumnsvalues)
+    * 3.12.5 [RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Values.ArrayFunctions](#rqsrs-018clickhousemapdatatypesubcolumnsvaluesarrayfunctions)
+    * 3.12.6 [RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Values.InlineDefinedMap](#rqsrs-018clickhousemapdatatypesubcolumnsvaluesinlinedefinedmap)
+  * 3.13 [Functions](#functions)
+    * 3.13.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.InlineDefinedMap](#rqsrs-018clickhousemapdatatypefunctionsinlinedefinedmap)
+    * 3.13.2 [`length`](#length)
+      * 3.13.2.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Length](#rqsrs-018clickhousemapdatatypefunctionslength)
+    * 3.13.3 [`empty`](#empty)
+      * 3.13.3.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Empty](#rqsrs-018clickhousemapdatatypefunctionsempty)
+    * 3.13.4 [`notEmpty`](#notempty)
+      * 3.13.4.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.NotEmpty](#rqsrs-018clickhousemapdatatypefunctionsnotempty)
+    * 3.13.5 [`map`](#map)
+      * 3.13.5.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map](#rqsrs-018clickhousemapdatatypefunctionsmap)
+      * 3.13.5.2 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.InvalidNumberOfArguments](#rqsrs-018clickhousemapdatatypefunctionsmapinvalidnumberofarguments)
+      * 3.13.5.3 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MixedKeyOrValueTypes](#rqsrs-018clickhousemapdatatypefunctionsmapmixedkeyorvaluetypes)
+      * 3.13.5.4 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MapAdd](#rqsrs-018clickhousemapdatatypefunctionsmapmapadd)
+      * 3.13.5.5 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MapSubstract](#rqsrs-018clickhousemapdatatypefunctionsmapmapsubstract)
+      * 3.13.5.6 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MapPopulateSeries](#rqsrs-018clickhousemapdatatypefunctionsmapmappopulateseries)
+    * 3.13.6 [`mapContains`](#mapcontains)
+      * 3.13.6.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.MapContains](#rqsrs-018clickhousemapdatatypefunctionsmapcontains)
+    * 3.13.7 [`mapKeys`](#mapkeys)
+      * 3.13.7.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.MapKeys](#rqsrs-018clickhousemapdatatypefunctionsmapkeys)
+    * 3.13.8 [`mapValues`](#mapvalues)
+      * 3.13.8.1 [RQ.SRS-018.ClickHouse.Map.DataType.Functions.MapValues](#rqsrs-018clickhousemapdatatypefunctionsmapvalues)
+
+## Revision History
+
+This document is stored in an electronic form using [Git] source control management software
+hosted in a [GitHub Repository].
+All the updates are tracked using the [Revision History].
+
+## Introduction
+
+This software requirements specification covers requirements for `Map(key, value)` data type in [ClickHouse].
+
+## Requirements
+
+### General
+
+#### RQ.SRS-018.ClickHouse.Map.DataType
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type that stores `key:value` pairs.
+
+### Performance
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Performance.Vs.ArrayOfTuples
+version:1.0
+
+[ClickHouse] SHALL provide comparable performance for `Map(key, value)` data type as
+compared to `Array(Tuple(K,V))` data type.
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Performance.Vs.TupleOfArrays
+version:1.0
+
+[ClickHouse] SHALL provide comparable performance for `Map(key, value)` data type as
+compared to `Tuple(Array(String), Array(String))` data type where the first
+array defines an array of keys and the second array defines an array of values.
+
+### Key Types
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Key.String
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type where key is of a [String] type.
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Key.Integer
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type where key is of an [Integer] type.
+
+### Value Types
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Value.String
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type where value is of a [String] type.
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Value.Integer
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type where value is of a [Integer] type.
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Value.Array
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type where value is of a [Array] type.
+
+### Invalid Types
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Invalid.Nullable
+version: 1.0
+
+[ClickHouse] SHALL not support creating table columns that have `Nullable(Map(key, value))` data type.
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Invalid.NothingNothing
+version: 1.0
+
+[ClickHouse] SHALL not support creating table columns that have `Map(Nothing, Nothing))` data type.
+
+### Duplicated Keys
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.DuplicatedKeys
+version: 1.0
+
+[ClickHouse] MAY support `Map(key, value)` data type with duplicated keys.
+
+### Array of Maps
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.ArrayOfMaps
+version: 1.0
+
+[ClickHouse] SHALL support `Array(Map(key, value))` data type.
+
+### Nested With Maps
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.NestedWithMaps
+version: 1.0
+
+[ClickHouse] SHALL support defining `Map(key, value)` data type inside the [Nested] data type.
+
+### Value Retrieval
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Value.Retrieval
+version: 1.0
+
+[ClickHouse] SHALL support getting the value from a `Map(key, value)` data type using `map[key]` syntax.
+If `key` has duplicates then the first `key:value` pair MAY be returned. 
+
+For example,
+
+```sql
+SELECT a['key2'] FROM table_map;
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Value.Retrieval.KeyInvalid
+version: 1.0
+
+[ClickHouse] SHALL return an error when key does not match the key type.
+
+For example,
+
+```sql
+SELECT map(1,2) AS m, m[1024]
+```
+
+Exceptions:
+
+* when key is `NULL` the return value MAY be `NULL`
+* when key value is not valid for the key type, for example it is out of range for [Integer] type, 
+  when reading from a table column it MAY return the default value for key data type
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Value.Retrieval.KeyNotFound
+version: 1.0
+
+[ClickHouse] SHALL return default value for the data type of the value
+when there's no corresponding `key` defined in the `Map(key, value)` data type. 
+
+
+### Converting Tuple(Array, Array) to Map
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.TupleOfArraysToMap
+version: 1.0
+
+[ClickHouse] SHALL support converting [Tuple(Array, Array)] to `Map(key, value)` using the [CAST] function.
+
+``` sql
+SELECT CAST(([1, 2, 3], ['Ready', 'Steady', 'Go']), 'Map(UInt8, String)') AS map;
+```
+
+``` text
+┌─map───────────────────────────┐
+│ {1:'Ready',2:'Steady',3:'Go'} │
+└───────────────────────────────┘
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.TupleOfArraysMap.Invalid
+version: 1.0
+
+[ClickHouse] MAY return an error when casting [Tuple(Array, Array)] to `Map(key, value)`
+
+* when arrays are not of equal size
+
+  For example,
+
+  ```sql
+  SELECT CAST(([2, 1, 1023], ['', '']), 'Map(UInt8, String)') AS map, map[10]
+  ```
+
+### Converting Array(Tuple(K,V)) to Map
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.ArrayOfTuplesToMap
+version: 1.0
+
+[ClickHouse] SHALL support converting [Array(Tuple(K,V))] to `Map(key, value)` using the [CAST] function.
+
+For example,
+
+```sql
+SELECT CAST(([(1,2),(3)]), 'Map(UInt8, UInt8)') AS map
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Conversion.From.ArrayOfTuplesToMap.Invalid
+version: 1.0
+
+[ClickHouse] MAY return an error when casting [Array(Tuple(K, V))] to `Map(key, value)`
+
+* when element is not a [Tuple]
+
+  ```sql
+  SELECT CAST(([(1,2),(3)]), 'Map(UInt8, UInt8)') AS map
+  ```
+
+* when [Tuple] does not contain two elements
+
+  ```sql
+  SELECT CAST(([(1,2),(3,)]), 'Map(UInt8, UInt8)') AS map
+  ```
+
+### Keys and Values Subcolumns
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Keys
+version: 1.0
+
+[ClickHouse] SHALL support `keys` subcolumn in the `Map(key, value)` type that can be used 
+to retrieve an [Array] of map keys.
+
+```sql
+SELECT m.keys FROM t_map;
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Keys.ArrayFunctions
+version: 1.0
+
+[ClickHouse] SHALL support applying [Array] functions to the `keys` subcolumn in the `Map(key, value)` type.
+
+For example,
+
+```sql
+SELECT * FROM t_map WHERE has(m.keys, 'a');
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Keys.InlineDefinedMap
+version: 1.0
+
+[ClickHouse] MAY not support using inline defined map to get `keys` subcolumn.
+
+For example,
+
+```sql
+SELECT map( 'aa', 4, '44' , 5) as c, c.keys
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Values
+version: 1.0
+
+[ClickHouse] SHALL support `values` subcolumn in the `Map(key, value)` type that can be used 
+to retrieve an [Array] of map values.
+
+```sql
+SELECT m.values FROM t_map;
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Values.ArrayFunctions
+version: 1.0
+
+[ClickHouse] SHALL support applying [Array] functions to the `values` subcolumn in the `Map(key, value)` type.
+
+For example,
+
+```sql
+SELECT * FROM t_map WHERE has(m.values, 'a');
+```
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.SubColumns.Values.InlineDefinedMap
+version: 1.0
+
+[ClickHouse] MAY not support using inline defined map to get `values` subcolumn.
+
+For example,
+
+```sql
+SELECT map( 'aa', 4, '44' , 5) as c, c.values
+```
+
+### Functions
+
+#### RQ.SRS-018.ClickHouse.Map.DataType.Functions.InlineDefinedMap
+version: 1.0
+
+[ClickHouse] SHALL support using inline defined maps as an argument to map functions.
+
+For example,
+
+```sql
+SELECT map( 'aa', 4, '44' , 5) as c, mapKeys(c)
+SELECT map( 'aa', 4, '44' , 5) as c, mapValues(c)
+```
+
+#### `length`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Length
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type as an argument to the [length] function
+that SHALL return number of keys in the map.
+
+For example,
+
+```sql
+SELECT length(map(1,2,3,4))
+SELECT length(map())
+```
+
+#### `empty`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Empty
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type as an argument to the [empty] function
+that SHALL return 1 if number of keys in the map is 0 otherwise if the number of keys is 
+greater or equal to 1 it SHALL return 0.
+
+For example,
+
+```sql
+SELECT empty(map(1,2,3,4))
+SELECT empty(map())
+```
+
+#### `notEmpty`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.NotEmpty
+version: 1.0
+
+[ClickHouse] SHALL support `Map(key, value)` data type as an argument to the [notEmpty] function
+that SHALL return 0 if number if keys in the map is 0 otherwise if the number of keys is
+greater or equal to 1 it SHALL return 1.
+
+For example,
+
+```sql
+SELECT notEmpty(map(1,2,3,4))
+SELECT notEmpty(map())
+```
+
+#### `map`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map
+version: 1.0
+
+[ClickHouse] SHALL support arranging `key, value` pairs into `Map(key, value)` data type
+using `map` function.
+
+**Syntax** 
+
+``` sql
+map(key1, value1[, key2, value2, ...])
+```
+
+For example,
+
+``` sql
+SELECT map('key1', number, 'key2', number * 2) FROM numbers(3);
+
+┌─map('key1', number, 'key2', multiply(number, 2))─┐
+│ {'key1':0,'key2':0}                              │
+│ {'key1':1,'key2':2}                              │
+│ {'key1':2,'key2':4}                              │
+└──────────────────────────────────────────────────┘
+```
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.InvalidNumberOfArguments
+version: 1.0
+
+[ClickHouse] SHALL return an error when `map` function is called with non even number of arguments.
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MixedKeyOrValueTypes
+version: 1.0
+
+[ClickHouse] SHALL return an error when `map` function is called with mixed key or value types.
+
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MapAdd
+version: 1.0
+
+[ClickHouse] SHALL support converting the results of `mapAdd` function to a `Map(key, value)` data type.
+
+For example,
+
+``` sql
+SELECT CAST(mapAdd(([toUInt8(1), 2], [1, 1]), ([toUInt8(1), 2], [1, 1])), "Map(Int8,Int8)")
+```
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MapSubstract
+version: 1.0
+
+[ClickHouse] SHALL support converting the results of `mapSubstract` function to a `Map(key, value)` data type.
+
+For example,
+
+```sql
+SELECT CAST(mapSubtract(([toUInt8(1), 2], [toInt32(1), 1]), ([toUInt8(1), 2], [toInt32(2), 1])), "Map(Int8,Int8)")
+```
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.Map.MapPopulateSeries
+version: 1.0
+
+[ClickHouse] SHALL support converting the results of `mapPopulateSeries` function to a `Map(key, value)` data type.
+
+For example,
+
+```sql
+SELECT CAST(mapPopulateSeries([1,2,4], [11,22,44], 5), "Map(Int8,Int8)")
+```
+
+#### `mapContains`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.MapContains
+version: 1.0
+
+[ClickHouse] SHALL support `mapContains(map, key)` function to check weather `map.keys` contains the `key`.
+
+For example,
+
+```sql
+SELECT mapContains(a, 'abc') from table_map;
+```
+
+#### `mapKeys`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.MapKeys
+version: 1.0
+
+[ClickHouse] SHALL support `mapKeys(map)` function to return all the map keys in the [Array] format.
+
+For example,
+
+```sql
+SELECT mapKeys(a) from table_map;
+```
+
+#### `mapValues`
+
+##### RQ.SRS-018.ClickHouse.Map.DataType.Functions.MapValues
+version: 1.0
+
+[ClickHouse] SHALL support `mapValues(map)` function to return all the map values in the [Array] format.
+
+For example,
+
+```sql
+SELECT mapValues(a) from table_map;
+```
+
+[Nested]: https://clickhouse.tech/docs/en/sql-reference/data-types/nested-data-structures/nested/
+[length]: https://clickhouse.tech/docs/en/sql-reference/functions/array-functions/#array_functions-length
+[empty]: https://clickhouse.tech/docs/en/sql-reference/functions/array-functions/#function-empty
+[notEmpty]: https://clickhouse.tech/docs/en/sql-reference/functions/array-functions/#function-notempty
+[CAST]: https://clickhouse.tech/docs/en/sql-reference/functions/type-conversion-functions/#type_conversion_function-cast
+[Tuple]: https://clickhouse.tech/docs/en/sql-reference/data-types/tuple/
+[Tuple(Array,Array)]: https://clickhouse.tech/docs/en/sql-reference/data-types/tuple/
+[Array]: https://clickhouse.tech/docs/en/sql-reference/data-types/array/ 
+[String]: https://clickhouse.tech/docs/en/sql-reference/data-types/string/
+[Integer]: https://clickhouse.tech/docs/en/sql-reference/data-types/int-uint/
+[ClickHouse]: https://clickhouse.tech
+[GitHub Repository]: https://github.com/ClickHouse/ClickHouse/blob/master/tests/testflows/map_type/requirements/requirements.md 
+[Revision History]: https://github.com/ClickHouse/ClickHouse/commits/master/tests/testflows/map_type/requirements/requirements.md
+[Git]: https://git-scm.com/
+[GitHub]: https://github.com

tests/testflows/map_type/tests/common.py

@@ -0,0 +1,49 @@
+import uuid
+from collections import namedtuple
+
+from testflows.core import *
+from testflows.core.name import basename, parentname
+from testflows._core.testtype import TestSubType
+
+def getuid():
+    if current().subtype == TestSubType.Example:
+        testname = f"{basename(parentname(current().name)).replace(' ', '_').replace(',','')}"
+    else:
+        testname = f"{basename(current().name).replace(' ', '_').replace(',','')}"
+    return testname + "_" + str(uuid.uuid1()).replace('-', '_')
+
+@TestStep(Given)
+def allow_experimental_map_type(self):
+    """Set allow_experimental_map_type = 1
+    """
+    setting = ("allow_experimental_map_type", 1)
+    default_query_settings = None
+
+    try:
+        with By("adding allow_experimental_map_type to the default query settings"):
+            default_query_settings = getsattr(current().context, "default_query_settings", [])
+            default_query_settings.append(setting)
+        yield
+    finally:
+        with Finally("I remove allow_experimental_map_type from the default query settings"):
+            if default_query_settings:
+                try:
+                    default_query_settings.pop(default_query_settings.index(setting))
+                except ValueError:
+                    pass
+
+@TestStep(Given)
+def create_table(self, name, statement, on_cluster=False):
+    """Create table.
+    """
+    node = current().context.node
+    try:
+        with Given(f"I have a {name} table"):
+            node.query(statement.format(name=name))
+        yield name
+    finally:
+        with Finally("I drop the table"):
+            if on_cluster:
+                node.query(f"DROP TABLE IF EXISTS {name} ON CLUSTER {on_cluster}")
+            else:
+                node.query(f"DROP TABLE IF EXISTS {name}")

tests/testflows/regression.py

@@ -18,6 +18,7 @@ def regression(self, local, clickhouse_binary_path, stress=None, parallel=None):
     # Feature(test=load("ldap.regression", "regression"))(**args)
     # Feature(test=load("rbac.regression", "regression"))(**args)
     # Feature(test=load("aes_encryption.regression", "regression"))(**args)
+    Feature(test=load("map_type.regression", "regression"))(**args)
     # Feature(test=load("kerberos.regression", "regression"))(**args)
 
 if main():