gitlab-org--gitlab-foss/doc/update/mysql_to_postgresql.md

Use the shell commands below to convert a MySQL GitLab database to a PostgreSQL one.

Export from MySQL and import into Postgres

Use this if you are keeping GitLab on the same server.

git clone https://github.com/lanyrd/mysql-postgresql-converter.git
cd mysql-postgresql-converter
mysqldump --compatible=postgresql --default-character-set=utf8 -r databasename.mysql -u root gitlabhq_production
python db_converter.py databasename.mysql databasename.psql
psql -f databasename.psql -d gitlabhq_production

Converting a GitLab backup file from MySQL to Postgres

GitLab backup files (_gitlab_backup.tar) contain a SQL dump. Using the lanyrd database converter we can replace a MySQL database dump inside the tar file with a Postgres database dump. This can be useful if you are moving to another server.

# Stop GitLab
sudo service gitlab stop

# Create the backup
cd /home/git/gitlab
sudo -u git -H bundle exec rake gitlab:backup:create RAILS_ENV=production

# Note the filename of the backup that was created. We will call it
# TIMESTAMP_gitlab_backup.tar below.

# Move the backup file we will convert to its own directory
sudo -u git -H mkdir -p tmp/backups/postgresql
sudo -u git -H mv tmp/backups/TIMESTAMP_gitlab_backup.tar tmp/backups/postgresql/

# Create a separate database dump with PostgreSQL compatibility
cd tmp/backups/postgresql
sudo -u git -H mysqldump --compatible=postgresql --default-character-set=utf8 -r gitlabhq_production.mysql -u root gitlabhq_production

# Clone the database converter
sudo -u git -H git clone https://github.com/lanyrd/mysql-postgresql-converter.git

# Convert gitlabhq_production.mysql
sudo -u git -H mkdir db
sudo -u git -H python mysql-postgresql-converter/db_converter.py gitlabhq_production.mysql db/database.sql

# Replace the MySQL dump in TIMESTAMP_gitlab_backup.tar.

# Warning: if you forget to replace TIMESTAMP below, tar will create a new file
# 'TIMESTAMP_gitlab_backup.tar' without giving an error.

sudo -u git -H tar rf TIMESTAMP_gitlab_backup.tar db/database.sql

# Done! TIMESTAMP_gitlab_backup.tar can now be restored into a Postgres GitLab installation.