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ClickHouse

clickhouse://host:port?username=user&password=password&database=clicks&x-multi-statement=true

URL Query Description
x-migrations-table Name of the migrations table
x-migrations-table-engine Engine to use for the migrations table, defaults to TinyLog
x-cluster-name Name of cluster for creating schema_migrations table cluster wide
database The name of the database to connect to
username The user to sign in as
password The user's password
host The host to connect to.
port The port to bind to.
x-multi-statement false

Notes

  • The Clickhouse driver does not natively support executing multiple statements in a single query. To allow for multiple statements in a single migration, you can use the x-multi-statement param. There are two important caveats:
    • This mode splits the migration text into separately-executed statements by a semi-colon ;. Thus x-multi-statement 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.
  • Using the default TinyLog table engine for the schema_versions table prevents backing up the table if using the clickhouse-backup tool. If backing up the database with make sure the migrations are run with x-migrations-table-engine=MergeTree.
  • Clickhouse cluster mode is not officially supported, since it's not tested right now, but you can try enabling schema_migrations table replication by specifying a x-cluster-name:
    • When x-cluster-name is specified, x-migrations-table-engine also should be specified. See the docs regarding replicated table engines.
    • When x-cluster-name is specified, only the schema_migrations table is replicated across the cluster. You still need to write your migrations so that the application tables are replicated within the cluster.
  • If you want to create database inside the migration, you should know, that table which will manage migrations schema-migrations table will be in default table, so you can't use USE <database_name> inside migration. In this case you may not specify the database in the connection string (example you can find here)