Migrate nextcloud v15 with mariadb database to nextcloud v16 with postgresql

If you are running nextcloud v15 with mariadb and want to upgrade from nextcloud version 16, then you have to migrate the database from mariadb to postgresql.

This can be done using the following commands, which I adjusted for ubuntu 16.04 and is originally from the following site: https://www.techandme.se/we-migrated-to-postgresql/
 

#!/bin/bash

## Convert to PostgreSQL ##
# Tested on Ubuntu Server 16.04
# Make sure you have a full backup of your nextcloud installation


# Make sure only root can run our script
if [[ $EUID -ne 0 ]]; then
 echo "This script must be run as root, please type sudo -i and run it again." 1>&2
 exit 1
fi

service apache2 stop

. <(curl -sL https://raw.githubusercontent.com/nextcloud/vm/master/lib.sh)

NCUSER=pgsql_user_nextcloud

# Install PostgreSQL
apt update
check_command apt install postgresql-9.5

# Create DB
cd /tmp || exit
sudo -u postgres psql <<END
CREATE USER $NCUSER WITH PASSWORD '$PGDB_PASS';
CREATE DATABASE nextcloud_db WITH OWNER $NCUSER TEMPLATE template0 ENCODING 'UTF8';
END
check-command service postgresql restart

# Convert DB
sudo -u www-data php /var/www/nextcloud/occ db:convert-type --all-apps --password "$PGDB_PASS" pgsql $NCUSER 127.0.0.1 nextcloud_db
sudo -u www-data php /var/www/nextcloud/occ maintenance:repair

# Remove MySQL / MariaDB
read -p "Are you sure you want to remove MySQL?" -n 1 -r
echo
if [[ $REPLY =~ ^[Yy]$ ]]
then
    apt clean
    apt update
    dpkg -r mariadb-client-10.2
    dpkg -r mariadb-server-10.2
    dpkg -r libmysqlclient20:i386
    dpkg -r libmysqlclient20:amd64
    dpkg -r libmysqlclient18:amd64
    dpkg -r mysql
    apt purge mysql\* libmysql\* libmariadb\*
    apt autoremove -y
    rm -R /var/lib/mysql /var/lib/mysql-files /var/lib/mysql-keyring /var/mysql-upgrade /etc/mysql /var/lib/mysql
fi

# Remove mysql.utf8mb4
if grep -q "mysql.utf8mb4" /var/www/nextcloud/config/config.php
then
sed -i "s|'mysql.utf8mb4' => true,||g" /var/www/nextcloud/config/config.php
sed '/^\s*$/d' /var/www/nextcloud/config/config.php
fi

# Show password
echo "Your new PostgreSQL password is: $PGDB_PASS. It's also written in your Nextcloud config.php file."

# Start Apache2
echo "Apache will start in 30 seconds... Press CTRL+C to abort."
sleep 30
service apache2 start

# Fetch the correct update script
if [ -f "$SCRIPTS"/update.sh ]
then
 rm "$SCRIPTS"/update.sh
 wget https://raw.githubusercontent.com/nextcloud/vm/master/static/update.sh -P "$SCRIPTS"
 chmod +x "$SCRIPTS"/update.sh
fi

exit