Gitlab do not recommend using MySQL due to various issues. For example, case (in)sensitivity and problems that suggested fixes have.
# Install the database packages
brew install mysql
ln -sfv /usr/local/opt/mysql/*.plist ~/Library/LaunchAgents
launchctl load ~/Library/LaunchAgents/homebrew.mxcl.mysql.plist
# Ensure you have MySQL version 5.5.14 or later
mysql --version
# Pick a MySQL root password (can be anything), type it and press enter
# Retype the MySQL root password and press enter
# Secure your installation
sudo mysql_secure_installation
# Login to MySQL
mysql -u root -p
# Type the MySQL root password
# Create a user for GitLab
# do not type the 'mysql>', this is part of the prompt
# change $password in the command below to a real password you pick
mysql> CREATE USER 'git'@'localhost' IDENTIFIED BY '$password';
# Ensure you can use the InnoDB engine which is necessary to support long indexes
# If this fails, check your MySQL config files (e.g. `/etc/mysql/*.cnf`, `/etc/mysql/conf.d/*`) for the setting "innodb = off"
mysql> SET storage_engine=INNODB;
# Create the GitLab production database
mysql> CREATE DATABASE IF NOT EXISTS `gitlabhq_production` DEFAULT CHARACTER SET `utf8` COLLATE `utf8_unicode_ci`;
# Grant the GitLab user necessary permissions on the database
mysql> GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, CREATE TEMPORARY TABLES, DROP, INDEX, ALTER, LOCK TABLES ON `gitlabhq_production`.* TO 'git'@'localhost';
# Quit the database session
mysql> \q
# Try connecting to the new database with the new user
sudo -u git -H mysql -u git -p -D gitlabhq_production
# Type the password you replaced $password with earlier
# You should now see a 'mysql>' prompt
# Quit the database session
mysql> \q
# You are done installing the database and can go back to the rest of the installation.