Building of ClickHouse is supported on Linux, FreeBSD and Mac OS X.
If you use Windows, you need to create a virtual machine with Ubuntu. To start working with a virtual machine please install VirtualBox. You can download Ubuntu from the website: https://www.ubuntu.com/#download. Please create a virtual machine from the downloaded image (you should reserve at least 4GB of RAM for it). To run a command-line terminal in Ubuntu, please locate a program containing the word “terminal” in its name (gnome-terminal, konsole etc.) or just press Ctrl+Alt+T.
ClickHouse cannot work or build on a 32-bit system. You should acquire access to a 64-bit system and you can continue reading.
To start working with ClickHouse repository you will need a GitHub account.
You probably already have one, but if you don’t, please register at https://github.com. In case you do not have SSH keys, you should generate them and then upload them on GitHub. It is required for sending over your patches. It is also possible to use the same SSH keys that you use with any other SSH servers - probably you already have those.
Create a fork of ClickHouse repository. To do that please click on the “fork” button in the upper right corner at https://github.com/ClickHouse/ClickHouse. It will fork your own copy of ClickHouse/ClickHouse to your account.
The development process consists of first committing the intended changes into your fork of ClickHouse and then creating a “pull request” for these changes to be accepted into the main repository (ClickHouse/ClickHouse).
To work with git repositories, please install
To do that in Ubuntu you would run in the command line terminal:
sudo apt update sudo apt install git
A brief manual on using Git can be found here: https://services.github.com/on-demand/downloads/github-git-cheat-sheet.pdf.
For a detailed manual on Git see https://git-scm.com/book/en/v2.
Next, you need to download the source files onto your working machine. This is called “to clone a repository” because it creates a local copy of the repository on your working machine.
In the command line terminal run:
git clone --recursive [email protected]:your_github_username/ClickHouse.git cd ClickHouse
Note: please, substitute your_github_username with what is appropriate!
This command will create a directory
ClickHouse containing the working copy of the project.
It is important that the path to the working directory contains no whitespaces as it may lead to problems with running the build system.
Please note that ClickHouse repository uses
submodules. That is what the references to additional repositories are called (i.e. external libraries on which the project depends). It means that when cloning the repository you need to specify the
--recursive flag as in the example above. If the repository has been cloned without submodules, to download them you need to run the following:
git submodule init git submodule update
You can check the status with the command:
git submodule status.
If you get the following error message:
Permission denied (publickey). fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists.
It generally means that the SSH keys for connecting to GitHub are missing. These keys are normally located in
~/.ssh. For SSH keys to be accepted you need to upload them in the settings section of GitHub UI.
You can also clone the repository via https protocol:
git clone https://github.com/ClickHouse/ClickHouse.git
This, however, will not let you send your changes to the server. You can still use it temporarily and add the SSH keys later replacing the remote address of the repository with
git remote command.
You can also add original ClickHouse repo’s address to your local repository to pull updates from there:
git remote add upstream [email protected]:ClickHouse/ClickHouse.git
After successfully running this command you will be able to pull updates from the main ClickHouse repo by running
git pull upstream master.
Working with submodules in git could be painful. Next commands will help to manage it:
# ! each command accepts --recursive # Update remote URLs for submodules. Barely rare case git submodule sync # Add new submodules git submodule init # Update existing submodules to the current state git submodule update # Two last commands could be merged together git submodule update --init
The next commands would help you to reset all submodules to the initial state (!WARNING! - any changes inside will be deleted):
# Synchronizes submodules' remote URL with .gitmodules git submodule sync --recursive # Update the registered submodules with initialize not yet initialized git submodule update --init --recursive # Reset all changes done after HEAD git submodule foreach git reset --hard # Clean files from .gitignore git submodule foreach git clean -xfd # Repeat last 4 commands for all submodule git submodule foreach git submodule sync --recursive git submodule foreach git submodule update --init --recursive git submodule foreach git submodule foreach git reset --hard git submodule foreach git submodule foreach git clean -xfd
ClickHouse uses CMake and Ninja for building.
CMake - a meta-build system that can generate Ninja files (build tasks).
Ninja - a smaller build system with a focus on the speed used to execute those cmake generated tasks.
To install on Ubuntu, Debian or Mint run
sudo apt install cmake ninja-build.
On CentOS, RedHat run
sudo yum install cmake ninja-build.
If you use Arch or Gentoo, you probably know it yourself how to install CMake.
For installing CMake and Ninja on Mac OS X first install Homebrew and then install everything else via brew:
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" brew install cmake ninja
Next, check the version of CMake:
cmake --version. If it is below 3.3, you should install a newer version from the website: https://cmake.org/download/.
ClickHouse uses several external libraries for building. All of them do not need to be installed separately as they are built together with ClickHouse from the sources located in the submodules. You can check the list in
Compilers GCC starting from version 9 and Clang version 8 or above are 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.
To install GCC on Ubuntu run:
sudo apt install gcc g++
Check the version of gcc:
gcc --version. If it is below 9, then follow the instruction here: https://clickhouse.tech/docs/en/development/build/#install-gcc-9.
Mac OS X build is supported only for Clang. Just run
brew install llvm
If you decide to use Clang, you can also install
lld, if you know what it is. Using
ccache is also recommended.
Now that you are ready to build ClickHouse we recommend you to create a separate directory
ClickHouse that will contain all of the build artefacts:
mkdir build cd build
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 9 gcc compiler in this example).
export CC=gcc-9 CXX=g++-9 cmake ..
Mac OS X:
export CC=clang CXX=clang++ cmake ..
CC variable specifies the compiler for C (short for C Compiler), and
CXX variable instructs which C++ compiler is to be used for building.
For a faster build, you can resort to the
debug build type - a build with no optimizations. For that supply the following parameter
cmake -D CMAKE_BUILD_TYPE=Debug ..
You can change the type of build by running this command in the
Run ninja to build:
ninja clickhouse-server clickhouse-client
Only the required binaries are going to be built in this example.
If you require to build all the binaries (utilities and tests), you should run ninja with no parameters:
Full build requires about 30GB of free disk space or 15GB to build the main binaries.
When a large amount of RAM is available on build machine you should limit the number of build tasks run in parallel with
ninja -j 1 clickhouse-server clickhouse-client
On machines with 4GB of RAM, it is recommended to specify 1, for 8GB of RAM
-j 2 is recommended.
If you get the message:
ninja: error: loading 'build.ninja': No such file or directory, it means that generating a build configuration has failed and you need to inspect the message above.
Upon the successful start of the building process, you’ll see the build progress - the number of processed tasks and the total number of tasks.
While building messages about protobuf files in libhdfs2 library like
libprotobuf WARNING may show up. They affect nothing and are safe to be ignored.
Upon successful build you get an executable file
ls -l programs/clickhouse
To run the server under the current user you need to navigate to
ClickHouse/programs/server/ (located outside of
build) and run:
In this case, ClickHouse will use config files located in the current directory. You can run
clickhouse server from any directory specifying the path to a config file as a command-line parameter
To connect to ClickHouse with clickhouse-client in another terminal navigate to
ClickHouse/build/programs/ and run
If you get
Connection refused message on Mac OS X or FreeBSD, try specifying host address 127.0.0.1:
clickhouse client --host 127.0.0.1
You can replace the production version of ClickHouse binary installed in your system with your custom-built ClickHouse binary. To do that install ClickHouse on your machine following the instructions from the official website. Next, run the following:
sudo service clickhouse-server stop sudo cp ClickHouse/build/programs/clickhouse /usr/bin/ sudo service clickhouse-server start
clickhouse-server and others are symlinks to the commonly shared
You can also run your custom-built ClickHouse binary with the config file from the ClickHouse package installed on your system:
sudo service clickhouse-server stop sudo -u clickhouse ClickHouse/build/programs/clickhouse server --config-file /etc/clickhouse-server/config.xml
If you do not know which IDE to use, we recommend that you use CLion. CLion is commercial software, but it offers 30 days free trial period. It is also free of charge for students. CLion can be used both on Linux and on Mac OS X.
KDevelop and QTCreator are other great alternatives of an IDE for developing ClickHouse. KDevelop comes in as a very handy IDE although unstable. If KDevelop crashes after a while upon opening project, you should click “Stop All” button as soon as it has opened the list of project’s files. After doing so KDevelop should be fine to work with.
As simple code editors, you can use Sublime Text or Visual Studio Code, or Kate (all of which are available on Linux).
Just in case, it is worth mentioning that CLion creates
build path on its own, it also on its own selects
debug for build type, for configuration it uses a version of CMake that is defined in CLion and not the one installed by you, and finally, CLion will use
make to run build tasks instead of
ninja. This is normal behaviour, just keep that in mind to avoid confusion.
The description of ClickHouse architecture can be found here: https://clickhouse.tech/docs/en/development/architecture/
The Code Style Guide: https://clickhouse.tech/docs/en/development/style/
Writing tests: https://clickhouse.tech/docs/en/development/tests/
List of tasks: https://github.com/ClickHouse/ClickHouse/contribute
Developing ClickHouse often requires loading realistic datasets. It is particularly important for performance testing. We have a specially prepared set of anonymized data from Yandex.Metrica. It requires additionally some 3GB of free disk space. Note that this data is not required to accomplish most of the development tasks.
Navigate to your fork repository in GitHub’s UI. If you have been developing in a branch, you need to select that branch. There will be a “Pull request” button located on the screen. In essence, this means “create a request for accepting my changes into the main repository”.
A pull request can be created even if the work is not completed yet. In this case please put the word “WIP” (work in progress) at the beginning of the title, it can be changed later. This is useful for cooperative reviewing and discussion of changes as well as for running all of the available tests. It is important that you provide a brief description of your changes, it will later be used for generating release changelogs.
Testing will commence as soon as Yandex employees label your PR with a tag “can be tested”. The results of some first checks (e.g. code style) will come in within several minutes. Build check results will arrive within half an hour. And the main set of tests will report itself within an hour.
The system will prepare ClickHouse binary builds for your pull request individually. To retrieve these builds click the “Details” link next to “ClickHouse build check” entry in the list of checks. There you will find direct links to the built .deb packages of ClickHouse which you can deploy even on your production servers (if you have no fear).
Most probably some of the builds will fail at first times. This is due to the fact that we check builds both with gcc as well as with clang, with almost all of existing warnings (always with the
-Werror flag) enabled for clang. On that same page, you can find all of the build logs so that you do not have to build ClickHouse in all of the possible ways.