REPLICATE DATABASE

Syntax

REPLICATE DATABASE db_name [WITH FORCE DIFFERENTIAL] FROM master_user[:'master_password']@master_host:master_port[/master_db_name]

Remarks

• db_name is the name of the target database on the secondary SingleStore instance. REPLICATE DATABASE will attempt to create a new database named db_name, unless the WITH FORCE DIFFERENTIAL clause is used. The database name on the secondary does not need to match the name of its corresponding remote primary database.

• REPLICATE DATABASE always replicates asynchronously.

• This command causes implicit commits. Refer to COMMIT for more information.

• If you run STOP REPLICATING, replication stops and the secondary database is promoted to the primary database on the local host. When replication stops, the promoted database will use synchronous replication, if the previous primary database used synchronous replication. Likewise, the promoted database will use asynchronous replication, if the previous primary database used asynchronous replication.

• The following applies if the secondary database were to be promoted to the primary database on the local host: If the promoted database uses synchronous replication, the former primary database’s durability setting is used. If the promoted database uses asynchronous replication, asynchronous durability is used. (In-memory database updates you make using DDL and DML are durable when they are also saved to the log on disk). For more information, see Replication and Durability Concepts.

• WITH FORCE DIFFERENTIAL replicates only the contents of the primary database that are not already in the secondary database. Most often, you should use the WITH FORCE DIFFERENTIAL clause to resume replication from the original primary database following a cluster failover. When you use this clause, a new database is not created, because the database already exists. This option cannot be used to do a failback.

• In case of multiple DR replications, for example, A -> B, A -> C, A -> D where A, B, C and D are databases, if you runSTOP REPLICATING for one replication (for example, stop A -> B), then you cannot run the REPLICATE DATABASE WITH FORCE DIFFERENTIAL command for the other replications.

• master_user should have relevant permissions. This user must have access to first do the resource check in the information schema in the primary database and then the initial replication setup. This user is only used to kickstart the replication, future replications will happen using internal SingleStore authentication negotiated during the REPLICATE handshake.  Hence this user need not exist after the REPLICATE command completes. You can switch to a different user to do the initial setup in future replications without making any modifications to the existing replications.

• master_password is assumed to be blank if it is not specified explicitly. If you specify a password, enclose it in single quotes.

• master_host is the host name or IPv4/IPv6 pointing to the remote database. It can be quoted to allow special characters (e.g. -, among others). master_host can be in the same cluster or in a different cluster than the local host.

• master_db_name is the name of the remote, primary database. If it is not specified explicitly, SingleStore attempts to replicate from db_name on the master SingleStore instance.

• While replicating, the database is in the replicating state (see Database States).

• If the primary database contains pipelines, the state of these pipelines (such as the pipeline offsets) are replicated to the secondary database.

• This command cannot be run on system databases.

• The replica database cannot be backed up.

• Queries can be run on the replica database.

• Refer to the Permission Matrix for the required permission.

Examples

REPLICATE DATABASE ExampleDatabase FROM root@master-host:3306;

REPLICATE DATABASE ExampleDatabase FROM master_user:'master_password'@master-host:3306/MasterExampleDatabase;