This repository now contains a collection of scripts for managing a replica of the MusicBrainz database.
The main motivation for these scripts is to be able to customize your database. If you don't need such customizations, it might be easier to use the replication tools provided by MusicBrainz itself.
You need to have Python 3.x installed on your system. You can use pipx to install this package:
sudo apt install python3 pipx pipx install 'mbslave'
There are two ways to configure the application.
You can use a config file:
curl https://raw.githubusercontent.com/acoustid/mbslave/main/mbslave.conf.default -o mbslave.conf vim mbslave.conf
By default, the
mbslave
script will look for the config file in the current directory. If you want it to find it from anywhere, either save it to/etc/mbslave.conf
or set theMBSLAVE_CONFIG
environment variable. For example::export MBSLAVE_CONFIG=/usr/local/etc/mbslave.conf
Alternativelly, you can use using environment variables:
export MBSLAVE_DB_HOST=127.0.0.1 export MBSLAVE_DB_PORT=5432 export MBSLAVE_DB_NAME=musicbrainz export MBSLAVE_DB_USER=musicbrainz export MBSLAVE_DB_PASSWORD=XXX export MBSLAVE_DB_ADMIN_USER=postgres export MBSLAVE_DB_ADMIN_PASSWORD=XXX
If you are starting from scratch and want a full copy of the MusicBrainz database,
you can use the mbslave init
command. This will create a new database and
populate it with the latest data from the MusicBrainz database:
mbslave init --create-user --create-database
This requires that you have PostgreSQL running and configured in a way, so
that mbslave
can connect to it both using a regular account as well as
superuser account. How you do that depends on your environment.
The other option is to create the database manually and use the mbslave psql
to apply the scripts from MusicBrainz. In this case you are expected to know what
you are doing.
You can also keep the database up-to-date by applying incrementa changes.
You need get an API token from the MetaBrainz website and you
need to either add it to mbslave.conf or set the MBSLAVE_MUSICBRAINZ_TOKEN
environment variable.
After that, you can use the mbslave sync
command to download the latest updates:
mbslave sync
When the MusicBrainz database schema changes, the replication will stop working. This is usually announced on the MusicBrainz blog. When it happens, you need to upgrade the database.
Run the upgrade scripts:
mbslave psql -f updates/schema-change/28.all.sql echo 'UPDATE replication_control SET current_schema_sequence = 28;' | mbslave psql
Run the upgrade scripts:
mbslave psql -f updates/schema-change/27.mirror.sql echo 'UPDATE replication_control SET current_schema_sequence = 27;' | mbslave psql
Run the upgrade scripts:
mbslave psql -f updates/schema-change/26.slave.sql echo 'UPDATE replication_control SET current_schema_sequence = 26;' | mbslave psql
These steps are recommended even if you were already running on Postgres 12 before MusicBrainz moved to make PostgreSQL 12 the minimal supported version.
Run the pre-upgrade script:
mbslave psql -f updates/20200518-pg12-before-upgrade.sql
If not already on PostgreSQL 12, upgrade your cluster now (depending on your OS, using pg_upgradecluster or pg_upgrade)
After upgrading, or if already on PostgreSQL 12, run:
mbslave psql -f updates/20200518-pg12-after-upgrade.sql
Run the upgrade scripts:
mbslave psql -f updates/schema-change/25.slave.sql echo 'UPDATE replication_control SET current_schema_sequence = 25;' | mbslave psql
Run the upgrade scripts:
mbslave psql -f updates/schema-change/24.slave.sql echo 'UPDATE replication_control SET current_schema_sequence = 24;' | mbslave psql
MusicBrainz uses a number of schemas by default. If you are embedding the MusicBrainz database into an existing database for your application, it's convenient to merge them all into a single schema. That can be done by changing your config like this:
[schemas] musicbrainz=musicbrainz statistics=musicbrainz cover_art_archive=musicbrainz wikidocs=musicbrainz documentation=musicbrainz
After this, you only need to create the "musicbrainz" schema and import all the tables there.
You can use the schema mapping feature to do zero-downtime upgrade of the database with full data import. You can temporarily map all schemas to e.g. "musicbrainz_NEW", import your new database there and then rename it:
echo 'BEGIN; ALTER SCHEMA musicbrainz RENAME TO musicbrainz_OLD; ALTER SCHEMA musicbrainz_NEW RENAME TO musicbrainz; COMMIT;' | mbslave psql -S