Clone the MySQL Git repository to your machine. The following command clones the MySQL Git repository to a directory named mysql-server. The initial download may take some time to complete, depending on the speed of your connection.

$> git clone https://github.com/mysql/mysql-server.git
Cloning into 'mysql-server'...
remote: Counting objects: 1198513, done.
remote: Total 1198513 (delta 0), reused 0 (delta 0), pack-reused 1198513
Receiving objects: 100% (1198513/1198513), 1.01 GiB | 7.44 MiB/s, done.
Resolving deltas: 100% (993200/993200), done.
Checking connectivity... done.
Checking out files: 100% (25510/25510), done.

When the clone operation completes, the contents of your local MySQL Git repository appear similar to the following:

~> cd mysql-server
~/mysql-server> ls
client             extra                mysys              storage
cmake              include              packaging          strings
CMakeLists.txt     INSTALL              plugin             support-files
components         libbinlogevents      README             testclients
config.h.cmake     libchangestreams     router             unittest
configure.cmake    libmysql             run_doxygen.cmake  utilities
Docs               libservices          scripts            VERSION
Doxyfile-ignored   LICENSE              share              vio
Doxyfile.in        man                  sql                win
doxygen_resources  mysql-test           sql-common

Use the git branch -r command to view the remote tracking branches for the MySQL repository.

~/mysql-server> git branch -r
  origin/5.7
  origin/8.0
  origin/HEAD -> origin/trunk
  origin/cluster-7.4
  origin/cluster-7.5
  origin/cluster-7.6
  origin/trunk

To view the branch that is checked out in your local repository, issue the git branch command. When you clone the MySQL Git repository, the latest MySQL branch is checked out automatically. The asterisk identifies the active branch.

~/mysql-server$ git branch
* trunk

To check out an earlier MySQL branch, run the git checkout command, specifying the branch name. For example, to check out the MySQL 8.0 branch:

~/mysql-server$ git checkout 8.0
Checking out files: 100% (9600/9600), done.
Branch 8.0 set up to track remote branch 8.0 from origin.
Switched to a new branch '8.0'

To obtain changes made after your initial setup of the MySQL Git repository, switch to the branch you want to update and issue the git pull command:

~/mysql-server$ git checkout trunk
~/mysql-server$ git pull

To examine the commit history, use the git log command:

~/mysql-server$ git log

You can also browse commit history and source code on the GitHub MySQL site.

If you see changes or code that you have a question about, ask on MySQL Community Slack.

After you have cloned the MySQL Git repository and have checked out the branch you want to build, you can build MySQL Server from the source code. Instructions are provided in Section 2.8.4, “Installing MySQL Using a Standard Source Distribution”, except that you skip the part about obtaining and unpacking the distribution.

Be careful about installing a build from a distribution source tree on a production machine. The installation command may overwrite your live release installation. If you already have MySQL installed and do not want to overwrite it, run CMake with values for the CMAKE_INSTALL_PREFIX, MYSQL_TCP_PORT, and MYSQL_UNIX_ADDR options different from those used by your production server. For additional information about preventing multiple servers from interfering with each other, see Section 7.8, “Running Multiple MySQL Instances on One Machine”.

Play hard with your new installation. For example, try to make new features crash. Start by running make test. See The MySQL Test Suite.