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 # 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.