Python library for creating and applying migrations in ClickHouse database.
Development and Maintenance of large-scale db systems many times requires constant changes to the actual DB system. Holding off the scripts to migrate these will be painful.
- Supports multi statements - more than one query per migration file.
- Allow running migrations out-of-box
- Simple file migrations format: {VERSION}_{name}.sql
- Supports Cluster deployments, makes sure that migrations state is consistent on all cluster nodes
This package originally forked from clickhouse-migrator.
| Package | Differences |
|---|---|
| clickhouse-migrator | Doesn't support multistatement in a single file , to heavy because of pandas, looks like abandoned |
| django-clickhouse | Need django |
| clickhouse-migrate | Doesn't support multistatement |
You can install from pypi using pip install clickhouse-migrations.
clickhouse-migrations --db-host localhost \
--db-user default \
--db-password secret \
--db-name test \
--migrations-dir ./migrationsfrom clickhouse_migrations.clickhouse_cluster import ClickhouseCluster
cluster = ClickhouseCluster(db_host, db_user, db_password)
cluster.migrate(db_name, migrations_home, cluster_name=None,create_db_if_no_exists=True, multi_statement=True)| Parameter | Description | Default |
|---|---|---|
| db_host | Clickhouse database hostname | localhost |
| db_port | Clickhouse database port | 9000 |
| db_user | Clickhouse user | default |
| db_password | Clichouse password | default |
| db_name | Clickhouse database name | None |
| migrations_home | Path to list of migration files | <project_root> |
| cluster_name | Name of Clickhouse topology cluster from <remote_servers> | None |
| create_db_if_no_exists | If the db_name is not present, enabling this will create the db |
True |
| multi_statement | Allow multiple statements in migration files | True |
The Clickhouse driver does not natively support executing multipe statements in a single query. To allow for multiple statements in a single migration, you can use the multi_statement param. There are two important caveats:
- This mode splits the migration text into separately-executed statements by a semi-colon ;. Thus cannot be used when a statement in the migration contains a string with a semi-colon.
- The queries are not executed in any sort of transaction/batch, meaning you are responsible for fixing partial migrations.
