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 will 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
BUILD                cmd-line-utils       libservices          sql
CMakeLists.txt       config.h.cmake       man                  sql-common
COPYING              configure.cmake      mysql-test           storage
Docs                 dbug                 mysys                strings
Doxyfile-perfschema  extra                mysys_ssl            support-files
INSTALL              include              packaging            testclients
README               libbinlogevents      plugin               unittest
VERSION              libbinlogstandalone  rapid                vio
client               libevent             regex                win
cmake                libmysql             scripts              zlib

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

~/mysql-server$ git branch -r
  origin/5.5
  origin/5.6
  origin/5.7
  origin/8.0
  origin/HEAD -> origin/5.7
  origin/cluster-7.2
  origin/cluster-7.3
  origin/cluster-7.4
  origin/cluster-7.5

To view the branches that are checked out in your local repository, issue the git branch command. When you cloned the MySQL Git repository, the MySQL 5.7 branch was checked out automatically. The asterisk identifies the 5.7 branch as the active branch.

~/mysql-server$ git branch
* 5.7

To check out a different 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'

Run git branch to verify that the MySQL 8.0 branch is present. MySQL 8.0, which is the last branch you checked out, is marked by an asterisk indicating that it is the active branch.

~/mysql-server$ git branch
  5.7
* 8.0

Use the git checkout command to switch between branches. For example:

~/mysql-server$ git checkout 5.7

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 8.0
~/mysql-server$ git pull

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

~/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 the MySQL Community Slack. For information about contributing a patch, see Contributing to MySQL Server.

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 2.9.2, “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 5.8, “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 Section 29.1.2, “The MySQL Test Suite”.