clickhouse

ClickHouse

clickhouse://username:password@host:port/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 multipe 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.